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Apr
29th
Sun
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The time machine in our mind. The imagistic mental machinery that allows us to travel through time

            

Our ability to close our eyes and imagine the pleasures of Super Bowl Sunday or remember the excesses of New Year’s Eve is a fairly recent evolutionary development, and our talent for doing this is unparalleled in the animal kingdom. We are a race of time travelers, unfettered by chronology and capable of visiting the future or revisiting the past whenever we wish. If our neural time machines are damaged by illness, age or accident, we may become trapped in the present. (…)

Why did evolution design our brains to go wandering in time? Perhaps it’s because an experience is a terrible thing to waste. Moving around in the world exposes organisms to danger, so as a rule they should have as few experiences as possible and learn as much from each as they can. (…)

Time travel allows us to pay for an experience once and then have it again and again at no additional charge, learning new lessons with each repetition. When we are busy having experiences—herding children, signing checks, battling traffic—the dark network is silent, but as soon as those experiences are over, the network is awakened, and we begin moving across the landscape of our history to see what we can learn—for free.

Animals learn by trial and error, and the smarter they are, the fewer trials they need. Traveling backward buys us many trials for the price of one, but traveling forward allows us to dispense with trials entirely. Just as pilots practice flying in flight simulators, the rest of us practice living in life simulators, and our ability to simulate future courses of action and preview their consequences enables us to learn from mistakes without making them.

We don’t need to bake a liver cupcake to find out that it is a stunningly bad idea; simply imagining it is punishment enough. The same is true for insulting the boss and misplacing the children. We may not heed the warnings that prospection provides, but at least we aren’t surprised when we wake up with a hangover or when our waists and our inseams swap sizes. (…)

Perhaps the most startling fact about the dark network isn’t what it does but how often it does it. Neuroscientists refer to it as the brain’s default mode, which is to say that we spend more of our time away from the present than in it. People typically overestimate how often they are in the moment because they rarely take notice when they take leave. It is only when the environment demands our attention—a dog barks, a child cries, a telephone rings—that our mental time machines switch themselves off and deposit us with a bump in the here and now. We stay just long enough to take a message and then we slip off again to the land of Elsewhen, our dark networks awash in light.”

Daniel Gilbert, Professor of Psychology at Harvard University, Essay: The Brain: Time Travel in the Brain, TIME, Jan. 29, 2007. (Illustration for TIME by Jeffery Fischer).

Kurt Stocker: The time machine in our mind (2012)

                                            
                                          (Click image to open research paper in pdf)

Abstract:

"This article provides the first comprehensive conceptual account for the imagistic mental machinery that allows us to travel through time—for the time machine in our mind. It is argued that language reveals this imagistic machine and how we use it. Findings from a range of cognitive fields are theoretically unified and a recent proposal about spatialized mental time travel is elaborated on. The following novel distinctions are offered: external vs. internal viewing of time; “watching” time vs. projective “travel” through time; optional vs. obligatory mental time travel; mental time travel into anteriority or posteriority vs. mental time travel into the past or future; single mental time travel vs. nested dual mental time travel; mental time travel in episodic memory vs. mental time travel in semantic memory; and “seeing” vs. “sensing” mental imagery. Theoretical, empirical, and applied implications are discussed.”

"The theoretical strategy I adopt is to use language as an entree to a conceptual level that seems deeper than language itself (Pinker, 2007; Talmy, 2000). The logic of this strategy is in accordance with recent findings that many conceptualizations observed in language have also been found to exist in mental representations that are more basic than language itself. (…)

It is proposed that this strategy helps to uncover an imagistic mental machinery that allows us to travel through time—that this strategy helps us to uncover the time machine in our mind.

A central term used in this article is “the imagery structuring of time.” By this I refer to an invisible spatial scaffolding in our mental imagery across which temporal material can be splayed, the existence of which will be proposed in this article. At times it will be quite natural to assume that a space-to-time mapping in the sense of conceptual metaphor theory is involved in the structuring of this invisible scaffolding. (…)

It is thus for the present investigation more coherent to assume that mental time is basically constructed out of “spatialized” mental imagery—“spatialized” is another central term that I use in this article. I use it in the sense that it is neutral as to whether some of the imagery might be transferred via space-to-time mappings or whether some of the imagery might relate to space-to-time mappings only in an etymological sense. An example of temporal constructions that are readily characterized in terms of spatialized temporal imagery structuring are the conceptualizations underlying the use of before and after, conceptualizations that are often treated as having autonomous temporal status and as relating only etymologically to space.

The current investigation can refine this view somewhat, by postulating that spatialized temporal structures still play a very vital role in the imagery structuring underlying before and after. (…)

The theoretical strategy, to use linguistic expressions about time as an entree to conceptual structures about time that seem deeper than language itself, has been applied quite fruitfully, since it has allowed for the development of a rather comprehensive and precise conceptual account of the time machine in our mind. The theory is not an ad-hoc theory, since linguistic conceptualizations cannot be interpreted in a totally arbitrary way—for example language does not allow us to assume that a sentence such as I shopped at the store before I went home means that first the going home took place and then the shopping. In this respect the theory is to some degree already a data-guided theory, since linguistic expressions are data. However, the proposal of the theory that language has helped us to uncover a specific system of spatialized imagery structuring of time can only be evaluated by carrying out corresponding psychological (cognitive and neurocognitive) experiments and some ideas for such experiments have been presented. Since the time machine in our mind is a deeply fascinating apparatus, I am confident that theoretical and empirical investigations will continue to explore it.”

— Kurt Stocker, The time machine in our mind (pdf), Institute of Cognitive and Brain Sciences, University of California, Berkeley, CA, USA, 2012

See also:

☞ T. Suddendorf, D. Rose Addis and M C. Corballis, Mental time travel and the shaping of the human mind (pdf), The Royal Society, 2009.

Abstract: “Episodic memory, enabling conscious recollection of past episodes, can be distinguished from semantic memory, which stores enduring facts about the world. Episodic memory shares a core neural network with the simulation of future episodes, enabling mental time travel into both the past and the future. The notion that there might be something distinctly human about mental time travel has provoked ingenious attempts to demonstrate episodic memory or future simulation in nonhuman animals, but we argue that they have not yet established a capacity comparable to the human faculty. The evolution of the capacity to simulate possible future events, based on episodic memory, enhanced fitness by enabling action in preparation of different possible scenarios that increased present or future survival and reproduction chances. Human language may have evolved in the first instance for the sharing of past and planned future events, and, indeed, fictional ones, further enhancing fitness in social settings.”

☞ George Lakoff, Mark Johnson, Conceptual Metaphor in Everyday Language (pdf), The Journal of Philosophy, Vol 77, 1980.
Our sense of time is deeply entangled with memory
Time tag on Lapidarium notes

Oct
3rd
Mon
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Time and the Brain. Eagleman: ‘Time is not just as a neuronal computation—a matter for biological clocks—but as a window on the movements of the mind’

                               

"Instead of reality being passively recorded by the brain, it is actively constructed by it."

David Eagleman, Incognito: The Secret Lives of the Brain, Pantheon Books, 2011

Clocks offer at best a convenient fiction, [David Eagleman] says. They imply that time ticks steadily, predictably forward, when our experience shows that it often does the opposite: it stretches and compresses, skips a beat and doubles back.”

Just how many clocks we contain still isn’t clear. The most recent neuroscience papers make the brain sound like a Victorian attic, full of odd, vaguely labelled objects ticking away in every corner. The circadian clock, which tracks the cycle of day and night, lurks in the suprachiasmatic nucleus, in the hypothalamus. The cerebellum, which governs muscle movements, may control timing on the order of a few seconds or minutes. The basal ganglia and various parts of the cortex have all been nominated as timekeepers, though there’s some disagreement on the details.

The standard model, proposed by the late Columbia psychologist John Gibbon in the nineteen-seventies, holds that the brain has “pacemaker” neurons that release steady pulses of neurotransmitters. More recently, at Duke, the neuroscientist Warren Meck has suggested that timing is governed by groups of neurons that oscillate at different frequencies. At U.C.L.A., Dean Buonomano believes that areas throughout the brain function as clocks, their tissue ticking with neural networks that change in predictable patterns. “Imagine a skyscraper at night,” he told me. “Some people on the top floor work till midnight, while some on the lower floors may go to bed early. If you studied the patterns long enough, you could tell the time just by looking at which lights are on.”

Time isn’t like the other senses, Eagleman says. Sight, smell, touch, taste, and hearing are relatively easy to isolate in the brain. They have discrete functions that rarely overlap: it’s hard to describe the taste of a sound, the color of a smell, or the scent of a feeling. (Unless, of course, you have synesthesia—another of Eagleman’s obsessions.) But a sense of time is threaded through everything we perceive. It’s there in the length of a song, the persistence of a scent, the flash of a light bulb. “There’s always an impulse toward phrenology in neuroscience—toward saying, ‘Here is the spot where it’s happening,’ ” Eagleman told me. “But the interesting thing about time is that there is no spot. It’s a distributed property. It’s metasensory; it rides on top of all the others.”

The real mystery is how all this is coördinated. When you watch a ballgame or bite into a hot dog, your senses are in perfect synch: they see and hear, touch and taste the same thing at the same moment. Yet they operate at fundamentally different speeds, with different inputs. Sound travels more slowly than light, and aromas and tastes more slowly still. Even if the signals reached your brain at the same time, they would get processed at different rates. The reason that a hundred-metre dash starts with a pistol shot rather than a burst of light, Eagleman pointed out, is that the body reacts much more quickly to sound. Our ears and auditory cortex can process a signal forty milliseconds faster than our eyes and visual cortex—more than making up for the speed of light. It’s another vestige, perhaps, of our days in the jungle, when we’d hear the tiger long before we’d see it.

In Eagleman’s essay “Brain Time,” published in the 2009 collection “What’s Next? Dispatches on the Future of Science,” he borrows a conceit from Italo Calvino’s “Invisible Cities.” The brain, he writes, is like Kublai Khan, the great Mongol emperor of the thirteenth century. It sits enthroned in its skull, “encased in darkness and silence,” at a lofty remove from brute reality. Messengers stream in from every corner of the sensory kingdom, bringing word of distant sights, sounds, and smells. Their reports arrive at different rates, often long out of date, yet the details are all stitched together into a seamless chronology. The difference is that Kublai Khan was piecing together the past. The brain is describing the present—processing reams of disjointed data on the fly, editing everything down to an instantaneous now. (…)

[Eagleman] thought of time not just as a neuronal computation—a matter for biological clocks—but as a window on the movements of the mind. (…)

You feel it now—not in half a second. But perception and reality are often a little out of register, as the saccade experiment showed. If all our senses are slightly delayed, we have no context by which to measure a given lag. Reality is a tape-delayed broadcast, carefully censored before it reaches us.

“Living in the past may seem like a disadvantage, but it’s a cost that the brain is willing to pay,” Eagleman said. “It’s trying to put together the best possible story about what’s going on in the world, and that takes time.” Touch is the slowest of the senses, since the signal has to travel up the spinal cord from as far away as the big toe. That could mean that the over-all delay is a function of body size: elephants may live a little farther in the past than hummingbirds, with humans somewhere in between. The smaller you are, the more you live in the moment. (…)

[T]ime and memory are so tightly intertwined that they may be impossible to tease apart.

One of the seats of emotion and memory in the brain is the amygdala, he explained. When something threatens your life, this area seems to kick into overdrive, recording every last detail of the experience. The more detailed the memory, the longer the moment seems to last. “This explains why we think that time speeds up when we grow older,” Eagleman said—why childhood summers seem to go on forever, while old age slips by while we’re dozing. The more familiar the world becomes, the less information your brain writes down, and the more quickly time seems to pass. (…)

“Time is this rubbery thing,” Eagleman said. “It stretches out when you really turn your brain resources on, and when you say, ‘Oh, I got this, everything is as expected,’ it shrinks up.” The best example of this is the so-called oddball effect—an optical illusion that Eagleman had shown me in his lab. It consisted of a series of simple images flashing on a computer screen. Most of the time, the same picture was repeated again and again: a plain brown shoe. But every so often a flower would appear instead. To my mind, the change was a matter of timing as well as of content: the flower would stay onscreen much longer than the shoe. But Eagleman insisted that all the pictures appeared for the same length of time. The only difference was the degree of attention that I paid to them. The shoe, by its third or fourth appearance, barely made an impression. The flower, more rare, lingered and blossomed, like those childhood summers. (…)”

Burkhard Bilger speaking about David Eagleman, neuroscientist at Baylor College of Medicine, where he directs the Laboratory for Perception and Action and the Initiative on Neuroscience and Law, The Possibilian, The New Yorker, Aprill 25, 2011 (Illustration source)

See also:

David Eagleman on how we constructs reality, time perception, and The Secret Lives of the Brain
☞ David Eagleman, Brain Time, Edge, June 24, 2009 
David Eagleman on the conscious mind
The Experience and Perception of Time, Stanford Encyclopedia of Philosophy
Time tag on Lapidarium notes

Aug
7th
Sun
permalink

The relativity of now


source

Jul
28th
Thu
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Where Is Now? The Paradox Of The Present


The night sky is a time machine. Look out and you look back in time. But this “time travel by eyesight” is not just the province of astronomy. It’s as close as the machine on which you are reading these words. Your present exists at the mercy of many overlapping pasts. So where, then, is “now”?

As almost everyone knows, when you stare into the depths of space you are also looking back in time. Catch a glimpse of a relatively nearby star and you see it as it existed when, perhaps, Lincoln was president (if it’s 150 light-years away). Stars near the edge of our own galaxy are only seen as they appeared when the last ice age was in full bloom (30,000 light-years away). And those giant pinwheel assemblies of stars called galaxies are glimpsed, as they existed millions, hundreds of millions or even billions of years in the past. (…)

Stranger still, the sky we see at any moment defines not a single past but multiple overlapping pasts of different depths. The star’s image from 100 years ago and the galaxy image from 100 million years ago reach us at the same time. All of those “thens” define the same “now” for us.

The multiple, foliated pasts comprising our present would be weird enough if it was just a matter of astronomy. But the simple truth is that every aspect of our personal “now” is a layered impression of a world already lost to the past.

To understand how this works, consider the simple fact (…) all we know about the world comes to us via signals: light waves, sound waves and electrical impulses running along our nerves. These signals move at a finite speed. It always takes some finite amount of time for the signal to travel from the world to your body’s sensors (and on to your brain).

A distant galaxy, a distant mountain peak, the not very distant light fixture on the ceiling and even the intimacy of a loved one’s face all live in the past. Those overlapping pasts are times that you — in your “now” — are no longer a part of.

Signal travel time constitutes a delay and all those overlapping delays constitute an essential separation. The inner world of your experience is, in a temporal sense, cut off from the outer world you inhabit.

Let’s take a few examples. Light travels faster than any other entity in the physical universe, propagating with the tremendous velocity of c = 300,000,000 m/s. From high school physics you know that the time it takes a light signal moving at c to cross some distance D is simply t = D/c.

When you look at the mountain peak 30 kilometers away you see it not as it exists now but as it existed a 1/10,000 of a second ago. The light fixture three meters above your head is seen not as it exists now but as it was a hundred millionth of a second ago. Gazing into your partner’s eyes, you see her (or him) not for who they are but for who they were 10-10 of a second in the past. Yes, these numbers are small. Their implication, however, is vast.

We live, each of us, trapped in our own now.

The simple conclusions described above derive, in their way, from relativity theory and they seem to spell the death knell for a philosophical stance called Presentism. According to Presentism only the present moment has ontological validity. In other words: only the present truly exists; only the present is real.

Presentism holds an intuitive sway for many people. It just feels right. For myself, when I try and explore the texture of my own experience, I can’t help but feel a sense of the present’s dominance. Buddhism, with its emphasis on contemplative introspection, has developed a sophisticated presentist stance concerning the nature of reality. “Anyone who has ever mediated for anytime” the abbot of a Zen monastery once told me “finds that the past and future are illusions.”

Yes, but …

The reality that even light travels at a finite speed forces us to confront the strange fact that, at best, the present exists at the fractured center of many overlapping pasts.

So where, then, are we in time? Where is our “now” and how does it live in the midst of a universe comprised of so many “thens”?”

Adam Frank, US physicist, astronomer and writer, Department of Physics And Astronomy at University of Rochester, Where Is Now? The Paradox Of The Present, npr, July 26, 2011 (Picture source)

See also:

Adam Frank, Hidden In Plain View: The Physics Of Cloaking Time, Space And Experience, npr, July 19, 2011 (Image: Jonathan Nackstrand/AFP)

                       
                      The path light travels determines the image you see.

You never experience the world as it is. You only experience it in the way light brings it to you.

And light can be taught to lie.

Last week researchers at Cornell University announced they had created a time cloaking device. Using their machine they could hide an event from detection, even if it occurred in plain view of very capable detectors. (…)

Both experiments rely on the complex realization of a simple truth about our experience of the world. We have no “direct” knowledge of the world-in-of-itself but, instead, are forced to rely on signals carried to us from external objects. If the properties of the signals are somehow changed while they are traveling to us then our experience of the world is changed as well. (…)

Nature and light can, however, be manipulated in ways that can make illusions impossible to detect. This is the new physics of cloaking. (…)”

Thermodynamic Asymmetry in Time, Stanford Encyclopedia of Philosophy
The Experience and Perception of Time, Stanford Encyclopedia of Philosophy
Time tag on Lapidarium
Time tag on Lapidarium notes

Jul
17th
Sun
permalink

David Eagleman on how we constructs reality, time perception, and The Secret Lives of the Brain

   

How our brain constructs reality

The conscious mind—which is the part of you that flickers to life when you wake up in the morning: that bit of you—it’s like a stowaway on a transatlantic steamship, that’s taking credit for the journey, without acknowledging all the engineering underfoot.

I think what this means when we’re talking about knowing ourselves is exactly
what it meant when people were trying to understand our place in the cosmos,
400 years ago, when Galileo discovered the moons of Jupiter and realized that, in fact, we’re not at the center of things, but instead we’re way out on a distant edge. That’s essentially the same situation we’re in, where we’ve fallen from the center of ourselves.

But in Galileo’s case, what that caused is we now have a much more nuanced view of the cosmos. As Carl Sagan was fond of saying, it’s more wondrous and subtle than we could have ever imagined. And I think it’s exactly the same thing going on with the brain: we’re falling from the center of the brain, but what we’re discovering is that it’s much more amazing than we could have ever thought when we imagined that we were the ones sort of at the center of everything and driving the boat. (…)

As we want to go on this journey of exploring what the heck we’re made out of, the first thing to do is to recognize that what you’re seeing out there is not actually reality. You’re not sort of opening your eyes, and voila, there’s the world. Instead, your brain constructs the world. Your brain is trapped in darkness inside of your skull, and all it ever sees are electrical and chemical signals. So all the colors you see, and so on, that doesn’t really exist; that’s an interpretation by your brain. (…)

All we’re actually doing is seeing an internal model of the world; we’re not seeing what’s out there, we’re seeing just our internal model of it. And that’s why, when you move your eyes around, all you’re doing is updating that model.

And for that matter, when you blink your eyes and there are 80 milliseconds of blackness there, you don’t notice that, either. Because it’s not actually about what’s coming in the eyes; it’s about your internal construction. And, in fact, as I mention in the book, we don’t even need our eyes to see. When you are asleep and dreaming, your eyes are closed, but you’re having full, rich visual experience —because it’s the same process of running your visual cortex, and then you believe that you are seeing. (…)

Because all the brain ever sees are these electrical and chemical signals, and it doesn’t necessarily know or care which ones are coming in through the eyes, or the ears, or the fingertips, or smell, or taste. All these things get converted just to electrical signals.

And so, it turns out what the brain is really good at—and the cortex in particular —is in extracting information that has some sort of useful correlation with things in the outside world. And so, if you feed, let’s say, visual input into your ears, you will figure out how to see through your ears. Because the brain doesn’t care how it gets there; all it cares about is, Oh, there’s structure to this data that I can extract. (…)

I think it’s sort of the most amazing thing about the way brains are built, is they’re constantly reconfiguring their own circuitry. (…)

It turns out that one of the main jobs of the brain is to save energy; and the way that it does this is by predicting what is going to come next. And if it sort of has a pretty good prediction of what’s happening next, then it doesn’t need to burn a lot of energy when that thing happens, because it’s already foreseen it. (…)

So, the job of the brain is to figure out what’s coming next; and if you have successfully done it, then there’s no point in consciousness being a part of what’s going on. (…)

Time perception

You’re not passively just watching the river of time flow by. Instead, just like with visual illusions, your brain is actively constructing time. (…)

When you can predict something, not only does your consciousness not come
online, but it feels like it goes very fast. So, driving to work is very fast; but the
very first time you did it, it seemed to take very long time. And it’s because of the
novelty and the amount of energy you had to burn the first time you did it—
before you were able to predict it.

Essentially what prediction means, if it’s something you’re doing a lot, is that
you’re actually reconfiguring the circuitry of the brain. You’re actually getting
stuff down into the circuitry, which gives you speed and efficiency, but at the cost
of conscious access. (…)

It’s not only the way we see vision and time, but it’s all of our cognition: it’s our morals, it’s what we’re attracted to, it’s what we believe in. All of these things are served up from these subterranean caverns of the mind. We often don’t have any access to what’s going on down there, and why we believe the things we do, why we act the way we do. (…)

The “illusion of truth”

You give people statements to rate the truth value of, and then you bring them back a while later and you give them more statements to say whether they’re true or false, and so on. But it turns out that if you repeat some of the statements from the first time to the second time, just because the people have heard them before, whether or not it’s true and whether or not they even marked it as false last time, because they’re hearing it again— unconsciously they know they’ve heard it before—they’re more likely to rate it as true now. (…)

I think this is part of the brain toolbox that children need: to really practice and learn skepticism and critical thinking skills. (…)

Some thoughts aren’t thinkable, because of the way that thoughts are constrained by our biology

Yes. As far as thoughts that we’re not able to think, that’s an idea that I just love to explore, because there’s all kinds of stuff we can’t see. Just as an example, if you take the electromagnetic radiation spectrum, what we call visible light is just one ten-billionth of that spectrum. So, we’re only seeing a very tiny sliver of that, because we have biological receptors that are tuned to that little part of the spectrum. But radio signals, and cell phone signals, and television signals, all that stuff is going right through your body, because you happen not to have biological receptors for that part of the spectrum.

So, what that means is that there’s a particular slice of the world that you can see. And what I wanted to explore in the book is that there’s also a slice of the world that you can think. In other words, because of evolutionary pressures, our psychology has been carved to think certain thoughts—this is the field known as evolutionary psychology—and that means there are other thoughts that are just like the cell phone signals, and radio signals, and so on, that we can’t even access.

Just as an example, try being sexually attracted to something that you’re not—like a chicken or a frog. But chickens and frogs find that to be the greatest thing in the world, to look at another chicken or frog. We only find that with humans. So, different species, which have otherwise pretty similar brains, have these very specific differences about the kinds of thoughts they can think. (…)

As far as nature vs. nurture goes, the answer nowadays is always both. It’s sort of a dead question to ask—nature vs. nurture—because it is absolutely true that we do not come to the table as a blank slate; we have a lot of stuff that we come to the table with predisposed. But the whole rest of the process is an unpacking of the brain by world experience. (…)

The brain as the team of rivals. Rational vs. emotional

So, the way your brain ends up in the end is a very complicated tangle of genetics and environment. And environment includes, not only all of your childhood experiences and so on, but your in utero environment, toxins in the air, the things that you eat, experiences of abuse, and all of that stuff—and your culture; your culture has a lot to do with the way your brain gets wired up. (…)

One of the culminating issues in the book is that your brain is really like a team of rivals, where you have these different neural subpopulations that are always battling it out to control the one-output channel of your behavior; and you’ve got all these different networks that are fighting it out. And so, there are parts of your brain that can be xenophobic, and other parts of your brain that maybe decide to overwrite that, and they’re not xenophobic. And I think this gives us a much more nuanced view, in the end, of who we are, and also who other people are. (…)

When people do neuroimaging studies, you can actually find situations where it looks like you have some parts that are doing essentially a math problem in the brain, and other parts that really care about how things feel, and how they’ll make the body feel. And you can image these different networks, and you can also see when they’re fighting one another when trying to do some sort of moral decision-making.

So, probably the best way for us to look at it is that when we talk about reason vs. emotion, we’re talking about sort of a summary—sort of a shorthand way of talking about these different neural networks. And, of course, decisions can be much more complicated than that, often. But sometimes they can be essentially boiled down to that.

It’s funny; the ancient Greeks also felt that this was the right way to divide it.
Again, it’s an oversimplification, but the Greeks had this idea that life is like
you’re a charioteer, and you’re holding the white horse of reason and the black horse of passion, and they’re both always trying to pull you off the road in different directions, and your job is to keep down the middle. And that’s about right. They had some insight there into that you do have these competing networks. (…)

The field of artificial intelligence

The field of artificial intelligence has become stuck, and I’m trying to figure
out why. I think it’s because when programmers are trying to make a robot do something, they come up with solutions: like here’s how you find the block of
wood, here’s how you grip the block of wood, here’s how you stack the block of
wood, and so on. And each time they make a little subroutine to take care of a
little piece of the problem; then they say, OK, good; that part’s done.

But Mother Nature never does that. Mother Nature chronically reinvents things all the time—accidentally. Just by mutation, there are always new ways to do things, like detect motion, or control muscles, or whatever it is that it’s trying to do—pick up on new energy sources, and so on. And as a result, what you have are multiple ways of solving problems in real biological creatures.

They don’t divide up neatly into little modules, the same way that a computer
program does, but instead, for example, in the mammalian cortex it appears that Mother Nature probably came up with about three or four different ways to detect motion. And all of these act like parties in the neural parliament. They all sort of think that they know how to detect motion best, and they battle it out with the other parties.

And so, I think this is one of the main lessons that we get, when we look for it, in what happens when we see brain damage in people. You can lose aspects of your vision and not lose other aspects; or, often, you can get brain damage and you don’t see a deficit at all, even though you’ve just sort of bombed out part of what you would expect to give a deficit.

In other words, you have this very complicated interaction of these different
parties that are battling it out. And I think they, in general, don’t divide neatly
along the cortical and subcortical division, but instead, whether in lizard brains
or in our brains, these networks can be made up of subcortical and cortical parts
together. (…)

The illusion we have that we have control

The analogy of a young monarch who takes the throne of his country, and takes credit for the glory of the country without thinking about the thousands of workers who are making it all work. And that’s essentially the situation we’re in.

Take, just as an example, when you have an idea, you say, ‘Oh, I just thought of
something.’ But it wasn’t actually you that thought of it. Your brain has been
working on that behind the scenes for hours or days, consolidating information,
putting things together, and finally it serves up something to you. It serves up an
idea; and then you take credit for it. But this whole things leads to this very
interesting question about the illusion we have that we have control. (…)

What does this mean for responsibility?

I think what it means is that when we look at something like the legal system, something like blameworthiness is actually the wrong question for us to ask. I mentioned before that brains end up being an end result of a very complicated process of genes intertwining with environment. So, in the end, when there’s a brain standing in front of the judge’s bench, it doesn’t matter for us to say, OK, well, are you blameworthy; to what extent are you blameworthy; to what extent was it your biology vs. you; because it’s not clear that there’s any meaningful difference between those two things, anyway.

I’m not saying this forgives anybody. We still have to take people off the street if they’re breaking the law. But what it means is that asking the question of blameworthiness isn’t where we should be putting our time. Instead, all we need to be doing is having a forward-looking legal system, where we say what do we do with you from here?

We don’t care how you got here, because we can’t ever know. It might have been
in utero cocaine poisoning, childhood abuse, lead paint on the walls, and all of
these other things that influenced your brain development, but we can’t untangle
that. And it’s not anybody’s fault. It’s not your fault or anybody else’s. But we
can’t do anything about it.

So, all we need to do is say, given the kind of person you are now, what is the
probability of recidivism. In other words, how likely are you to transfer this
behavior to a future situation and re-offend? And then we can predicate sentence
length on that probability of re-offense. And, equally as importantly, along with
customized sentencing, we can have customized rehabilitation.

So, there are lots of things that can go wrong with people’s brains that we can
usefully address, and try to help people, instead of throwing everybody in jail. As it stands now, 30% of the prison population has mental illness. Not only is that not a humane way for us to treat our mentally ill and make a de facto healthcare system, but it’s also not cost-effective.

And it’s also criminogenic—meaning it causes more crime. Because everybody
knows when you put people in jail, that limits their employment opportunities, it
breaks their social circles, and they end up coming back to the jail, more often
than not. So, it’s very clear how the legal system should be straightening itself out, just to make itself forward-looking, and saying, OK, all we need to do is get good at assessing risk into the future. (…)

A neural parliament

One of the really amazing lessons is this bit about being a neural parliament,
and not being made up of just one thing. I think this gives us a much better view
of why we can argue with ourselves, and curse at ourselves, and contract with
ourselves, and why we can do things where we look back and we think, Wow,
how did I do that? I’m not the kind of person who would do that.

But, in fact, you are many people. As Walt Whitman said, “I am large, I contain multitudes.” So, I think this gives us a better view of ourselves, and it also tells us ways to set up our own behavior to become the kind of people we want to be, by thinking about how to structure things in our life so that the short-term parties that are interested in instant impulse gratification—so that they don’t always win the battle.”

David Eagleman, neuroscientist at Baylor College of Medicine, where he directs the Laboratory for Perception and Action and the Initiative on Neuroscience and Law, Interview with Dr. David Eagleman, Author of Incognito: The Secret Lives of the Brain, Brain Science Podcast, Episode #75, Originally Aired 7/8/2011 (transcript in pdf) (Illustration source: David Plunkert for TIME)

The brain… it makes you think. Doesn’t it?

David Eagleman: “A person is not a single entity of a single mind: a human is built of several parts, all of which compete to steer the ship of state. As a consequence, people are nuanced, complicated, contradictory. We act in ways that are sometimes difficult to detect by simple introspection. To know ourselves increasingly requires careful studies of the neural substrate of which we are composed. (…)

Raymond Tallis: Of course, everything about us, from the simplest sensation to the most elaborately constructed sense of self, requires a brain in some kind of working order. (…)

[But] we are not stand-alone brains. We are part of community of minds, a human world, that is remote in many respects from what can be observed in brains. Even if that community ultimately originated from brains, this was the work of trillions of brains over hundreds of thousands of years: individual, present-day brains are merely the entrance ticket to the drama of social life, not the drama itself. Trying to understand the community of minds in which we participate by imaging neural tissue is like trying to hear the whispering of woods by applying a stethoscope to an acorn. (…)

David Eagleman: The uses of neuroscience depend on the question being asked. Inquiries about economies, customs, or religious wars require an examination of what transpires between minds, not just within them. Indeed, brains and culture operate in a feedback loop, each influencing the other.

Nonetheless, culture does leave its signature in the circuitry of the individual brain. If you were to examine an acorn by itself, it could tell you a great deal about its surroundings – from moisture to microbes to the sunlight conditions of the larger forest. By analogy, an individual brain reflects its culture. Our opinions on normality, custom, dress codes and local superstitions are absorbed into our neural circuitry from the social forest around us. To a surprising extent, one can glimpse a culture by studying a brain. Moral attitudes toward cows, pigs, crosses and burkas can be read from the physiological responses of brains in different cultures.

Beyond culture, there are fruitful questions to be asked about individual experience. Your experience of being human – from thoughts to actions to pathologies to sensations – can be studied in your individual brain with some benefit. With such study, we can come to understand how we see the world, why we argue with ourselves, how we fall prey to cognitive illusions, and the unconscious data-streams of information that influence our opinions.

How did I become aware enough about unawareness to write about it in Incognito? It was an unlikely feat that required millennia of scientific observation by my predecessors. An understanding of the limitations of consciousness is difficult to achieve simply by consulting our intuition. It is revealed only by study.

To be clear, this limitation does not make us equivalent to automatons. But it does give a richer understanding of the wellspring of our ideas, moral intuitions, biases and beliefs. Sometimes these internal drives are genetically embedded, other times they are culturally instructed – but in all cases their mark ends up written into the fabric of the brain. (…)

Neuroscience is uncovering a bracing view of what’s happening below the radar of our conscious awareness, but that makes your life no more “helpless, ignorant, and zombie-like” than whatever your life is now. If you were to read a cardiology book to learn how your heart pumps, would you feel less alive and more despondently mechanical? I wouldn’t. Understanding the details of our own biological processes does not diminish the awe, it enhances it. Like flowers, brains are more beautiful when you can glimpse the vast, intricate, exotic mechanisms behind them.”

David Eagleman, neuroscientist at Baylor College of Medicine, where he directs the Laboratory for Perception and Action, bestselling author

Raymond Tallis, British philosopher, secular humanist, poet, novelist, cultural critic, former professor of geriatric medicine at Manchester University

The brain… it makes you think. Doesn’t it?, The Guardian, The Observer, 29 April 2012.

See also:

Time and the Brain. Eagleman: ‘Time is not just as a neuronal computation—a matter for biological clocks—but as a window on the movements of the mind’
David Eagleman on the conscious mind
David Eagleman on Being Yourselves, lecture at Conway Hall, London, 10 April 2011.
The Experience and Perception of Time, Stanford Encyclopedia of Philosophy
Your brain creates your sense of self, incognito, CultureLab, Apr 19, 2011.
Dean Buonomano on ‘Brain Bugs’ - Cognitive Flaws That ‘Shape Our Lives’
Iain McGilchrist on The Divided Brain and the Making of the Western World
Daniel Kahneman: The Marvels and the Flaws of Intuitive Thinking
The Relativity of Truth - a brief résumé, Lapidarium
Timothy D. Wilson on The Social Psychological Narrative: ‘It’s not the objective environment that influences people, but their constructs of the world’
☞ David Eagleman, Your Brain Knows a Lot More Than You Realize, DISCOVER Magazine, Oct 27, 2011
☞ David Eagleman, Henry Markram, Will We Ever Understand the Brain?, California Academy of Sciences San Francisco, CA, Fora.tv video, 11.02.2011
☞ Bruce Hood, The Self Illusion: How the Brain Creates Identity, May, 2012
Mind & Brain tag on Lapidarium

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How the brain stops time

“Fear does not actually speed up our rate of perception or mental processing. Instead, it allows us to remember what we do experience in greater detail. Since our perception of time is based on the number of things we remember, fearful experiences thus seem to unfold more slowly. Eagleman’s findings are important not just for understanding the experience of fear, but for the very nature of consciousness. (…)

Yet David Eagleman's findings suggest that that sensation could only have been superimposed after the fact. The implication is that we don’t really have a direct experience of what we’re feeling ‘right now,’ but only a memory - an unreliable memory - of what we thought it felt like some seconds or milliseconds ago. The vivid present tense we all think we inhabit might itself be a retroactive illusion."

Jeff Wise, How the Brain Stops Time, Psychology Today, March 13, 2010.

                     

"It’s not that our memory is a glitchy wetware version of computer flash memory; it’s that the computer metaphor just doesn’t apply. Henry Roediger said we store only bits and pieces of what happened—a smattering of impressions we weave together into feels like a seamless narrative. When we retrieve a memory, we also rewrite it, so that the time next we go to remember it, we don’t retrieve the original memory but the last one we recollected. So, each time we tell a story, we embellish it, while remaining genuinely convinced of the veracity of our memories. (…)

Our memory becomes distorted because our brains react more strongly to novelty than to repetition. David Eagleman investigated this effect by asking volunteers to estimate the duration of flashes of light; those flashes that were the first in a series, or broke an established pattern, seemed to last longer. This feature of consciousness, like the 80-millisecond rule, explain so much about our daily experience. When we’re sitting through a boring event, it seems to take forever. But when we look back on it, it went by in a flash. Conversely, when you’re doing something exciting, time seems to race by, but when you look back on it, it stretched out. In the first case, there was little to remember, so your brain collapsed the feeling of duration. In the second, there was so much to remember, so the event seemed to expand. Time flies when you’re having fun, but crawls when you recollect in tranquility. (…)

All theories of physics begin with sense-data. As Eagleman said, “We build our physics on top of our intuitions.”

We also build our physics on a recognition of the limits of perception. The whole point of theories such as relativity is to separate objective features of the world from artifacts of our perspective. One of the most important books of the past two decades on the physics and philosophy of time, Huw Price’s Time’s Arrow and Archimedes’ Point, argues that concepts of cause and effect derive from our experience as agents in the world and may not be a fundamental feature of reality.

George Musser, Time on the Brain: How You Are Always Living In the Past, and Other Quirks of Perception, Scientific American, Sept 15, 2011

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Robert Lanza: Does the Past Exist Yet? Evidence Suggests Your Past Isn’t Set in Stone

(Picture source)

“Recent discoveries require us to rethink our understanding of history. “The histories of the universe,” said renowned physicist Stephen Hawking “depend on what is being measured, contrary to the usual idea that the universe has an objective observer-independent history.”

Is it possible we live and die in a world of illusions? Physics tells us that objects exist in a suspended state until observed, when they collapse in to just one outcome. Paradoxically, whether events happened in the past may not be determined until sometime in your future — and may even depend on actions that you haven’t taken yet.

In 2002, scientists carried out an amazing experiment, which showed that particles of light “photons" knew — in advance −- what their distant twins would do in the future. They tested the communication between pairs of photons — whether to be either a wave or a particle. Researchers stretched the distance one of the photons had to take to reach its detector, so that the other photon would hit its own detector first. The photons taking this path already finished their journeys — they either collapse into a particle or don’t before their twin encounters a scrambling device. Somehow, the particles acted on this information before it happened, and across distances instantaneously as if there was no space or time between them. They decided not to become particles before their twin ever encountered the scrambler. It doesn’t matter how we set up the experiment. Our mind and its knowledge is the only thing that determines how they behave. Experiments consistently confirm these observer-dependent effects.

More recently (Science 315, 966, 2007), scientists in France shot photons into an apparatus, and showed that what they did could retroactively change something that had already happened. As the photons passed a fork in the apparatus, they had to decide whether to behave like particles or waves when they hit a beam splitter. Later on - well after the photons passed the fork - the experimenter could randomly switch a second beam splitter on and off. It turns out that what the observer decided at that point, determined what the particle actually did at the fork in the past. At that moment, the experimenter chose his history. (…)

But what about dinosaur fossils? Fossils are really no different than anything else in nature. For instance, the carbon atoms in your body are “fossils” created in the heart of exploding supernova stars. Bottom line: reality begins and ends with the observer. “We are participators,” John Wheeler said “in bringing about something of the universe in the distant past.” Before his death, he stated that when observing light from a quasar, we set up a quantum observation on an enormously large scale. It means, he said, the measurements made on the light now, determines the path it took billions of years ago.

Like the light from Wheeler’s quasar, historical events such as who killed JFK, might also depend on events that haven’t occurred yet. There’s enough uncertainty that it could be one person in one set of circumstances, or another person in another. Although JFK was assassinated, you only possess fragments of information about the event. But as you investigate, you collapse more and more reality. According to biocentrism, space and time are relative to the individual observer - we each carry them around like turtles with shells. (…)

History is a biological phenomenon − it’s the logic of what you, the animal observer experiences. You have multiple possible futures, each with a different history like in the Science experiment. Consider the JFK example: say two gunmen shot at JFK, and there was an equal chance one or the other killed him. This would be a situation much like the famous Schrödinger’s cat experiment, in which the cat is both alive and dead − both possibilities exist until you open the box and investigate.

“We must re-think all that we have ever learned about the past, human evolution and the nature of reality, if we are ever to find our true place in the cosmos,” says Constance Hilliard, a historian of science at UNT. Choices you haven’t made yet might determine which of your childhood friends are still alive, or whether your dog got hit by a car yesterday. In fact, you might even collapse realities that determine whether Noah’s Ark sank. “The universe,” said John Haldane, “is not only queerer than we suppose, but queerer than we can suppose.”

See also:

Biocentrism
The Experience and Perception of Time, Stanford Encyclopedia of Philosophy
Time tag on Lapidarium
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Hans Reichenbach, The Direction of Time, Courier Dover Publications, 1999, page 9. (via fuckyeahquantummechanics)

Hans Reichenbach, The Direction of Time, Courier Dover Publications, 1999, page 9. (via fuckyeahquantummechanics)

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Stephen Hawking on the universe’s origin

   
Picture: Starry-Eyed Hubble Celebrates 20 Years of Awe and Discovery / NASA Goddard Space Flight Center

“Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going. (…)”

The universe looks more and more like a quantum phenomenon, in which a multitude of histories diverge. This is what Hawking calls top-down cosmology. Space and time fizzle out, so it can’t be said that there is a time before the big bang — just as you can’t say that there is something north of the North Pole. (I’m talking “north,” not “up.”)

Gravity is part of the picture because it helps keep the cosmic balance sheet in line. (…) Because gravity shapes space and time, it allows space-time to be locally stable but globally unstable. On the scale of the entire universe, the positive energy of the matter can be balanced by the negative gravitational energy, and so there is no restriction on the creation of whole universes.”

Hawking says God’s not needed. So?, Cosmic Log on msnbc.com, Sep 2, 2010. See also Stephen Hawking, The Grand Design

Cosmology from the Top Down

“The bottom up approach is more problem in cosmology however, because we do not know what the initial state of the universe was, and we certainly can’t try out different initial states, and see what kinds of universe they produce. (…)

I think the universe may have had an initial de Sitter stage considerably larger than the Planck scale.

I now turn to pre Big Bang scenarios, which are the main alternative to inflation. I shall take them to include the Ekpyrotic and cyclic models, as well as the older pre big bang scenario. The observations of fluctuations in the microwave background, show that there are correlations on scales larger than the horizon size at decoupling. These correlations could be explained if there had been inflation, because the exponential expansion, would have meant that regions that are now widely separated, were once in causal contact with each other. On the other hand, if there were no inflation, the correlations must have been present at the beginning of the expansion of the universe. Presumably, they arose in a previous contracting phase, and somehow survived the singularity, or brane collision. It is not clear if effects can be transmitted through a singularity, or if they will produce the right signature in the microwave background. But even if the answer to both of these questions is yes, the pre big bang scenarios do not answer the central question of cosmology, why is the universe, the way it is. All the pre big bang scenarios can do, is shift the problem of the initial state from 13 point 7 billion years ago, to the infinite past. But a boundary condition is a boundary condition, even if the boundary is at infinity.The present state of the universe, would depend on the boundary condition in the infinite past. The trouble is, there’s no natural boundary condition, like the universe being in its ground state. The universe doesn’t have a ground state. It is unstable, and is either expanding or contracting. The lack of a preferred initial state in the infinite past, means that pre big bang scenarios, are no better at explaining the universe, than supposing that someone wound up the clockwork, and set the universe going at the big bang. (…)

     

                          Picture source: João E. Steiner, The origin of the universe

(…) One of the first acts of my research career, was to show with Roger Penrose, that any reasonable classical cosmological solution, has a singularity in the past. This implies that the origin of the universe, was a quantum event. This means that it should be described by the Feynman sum over histories. The universe doesn’t have just a single history, but every possible history, whether or not they satisfy the field equations. Some people make a great mystery of the multi universe, or the many worlds interpretation of quantum theory, but to me, these are just different expressions of the Feynman path integral. (…)

(…) there is no way one can rule out the final surface, from belonging to a different universe to the initial surface. In fact, because there are so many different possible universes, they will dominate, and the final state will be independent of the initial. It will be given by a path integral over all metrics whose only boundary is the final surface. In other words, it is the so called no boundary quantum state.

If one accepts that the no boundary proposal, is the natural prescription for the quantum state of the universe, one is led to a profoundly different view of cosmology, and the relation between cause and effect. One shouldn’t follow the history of the universe from the bottom up, because that assumes there’s a single history, with a well defined starting point and evolution. Instead, one should trace the histories from the top down, in other words, backwards from the measurement surface, S, at the present time. The histories that contribute to the path integral, don’t have an independent existence, but depend on the amplitude that is being measured. As an example of this, consider the apparent dimension of the universe. The usual idea is that spacetime is a four dimension nearly flat metric, cross a small six or seven dimensional internal manifold. But why aren’t theremore large dimensions. Thy are any dimensions compactified. There are good reasons to think that life is possible only in four dimensions, but most physicists are very reluctant to appeal to the anthropic principle. They would rather believe that there is some mechanism that causes all but four of the dimensions to compactify spontaneously. Alternatively, maybe all dimensions started small, but for some reason, four dimensions expanded, and the rest did not. I’m sorry to disappoint these hopes, but I don’ t think there is a dynamical reason for the universe to appear four dimensional. (…)

We live in a universe that appears four dimensional, so we are interested only in amplitudes for surfaces with three large dimensions. This may sound like the anthropic principle argument that the reason we observe the universe to be four dimensional, is that life is possible only in four dimensions. But the argument here is different, because it doesn’t depend on whether four dimensions, is the only arena for life. Rather it is that the probability distribution over dimensions is irrelevant, because we have already measured that we are in four dimensions. (…)

Many physicists believe that string theory, will uniquely predict the standard model, and the values of its 40 or so parameters. The bottom up picture would be that the universe would begin with some grand unified symmetry, like E8 cross E8. As the universe expanded and cooled, the symmetry would break to the standard model, maybe through intermediate stages. The hope would be that String theory, would predict the pattern of breaking, the mass, couplings and mixing angles. Personally, I find it difficult to believe that the standard model, is the unique prediction of fundamental theory. It is so ugly, and the mixing angles etc, seem accidental, rather than part of a grand design. (…)

In string stroke M theory, low energy particle physics is determined by the internal space. It is well known that M theory has solutions with many different internal spaces. If one builds the history of the universe from the bottom up, there is no reason it should end up with the internal space for the standard model. However, if one asks for the amplitude for a space like surface with a given internal space, one is interested only in those histories which end with that internal space. One therefore has to trace the histories from the top down, backwards from the final surface. (…)

How can one get a non zero amplitude for the present state of the universe, if as I claim, the metrics in the path integral, have no boundary apart from the surface at the present time. I can’t claim to have the definitive answer, but one possibility would be if the four dimensional part of the metric, went back to a de Sitter phase. Such a scenario is realized in trace anomaly driven inflation, for example. In the Lorentzian regime, the de Sitter phase would extend back into the infinite past. It would represent a universe that contracted to a minimum radius, and then expanded again. But as we know, Lorentzian de Sitter can be closed off in the past by half the four sphere. One can interpret this in the bottom up picture, as the spontaneous creation of an inflating universe from nothing. Some pre big bang or Ekpyrotic scenarios, involving collapsing and expanding universes, can probably be formulated in no boundary terms, with an orbifold point. However, this would remove the scale free perturbations which, it is claimed, develop during the collapse, and carry on into the expansion. So again it is a no no for pre big bang and Ekpyrotic universes.

In conclusion, the bottom up approach to cosmology, would be appropriate, if one knew that the universe was set going in a particular way, in either the finite, or infinite past. However, in the absence of such knowledge, it is better to work from the top down, by tracing backwards from the final surface, the histories that contribute to the path integral. This means that the histories of the universe, depend on what is being measured, contrary to the usual idea that the universe has an objective, observer independent, history. The Feynman path integral allows every possible history for the universe, and the observation, selects out the sub class of histories that have the property that is being observed. There are histories in which the universe eternally inflates, or is eleven dimensional, but they do not contribute to the amplitudes we measure. I would call this the selection principle, rather than the anthropic principle because it doesn’t depend on intelligent life. Life may after all be possible in eleven dimensions, but we know we live in four. (…)

We can’ t tell whether the universe was likely to have the values we observe, or whether it was just a lucky chance. However, it is note worthy that the parameters we measure seem to lie in the interior of the anthropically allowed range, rather than at one end. This suggests that the probability distribution is fairly flat, not like the exponential dependence on the density parameter, omega, in the open inflation that Neil Turok and I proposed. In that model, omega would have had the minimum value required to form a single galaxy, which is all that is anthropically necessary. All the other galaxies which we see, are superfluous.

Although the theory can not predict the average values of these quantities, it will predict that there will be spatial variations, like the fluctuations in the microwave background. However the size of these variations, will probably depend on moduli or parameters that we can’ t predict. So even when we understand the ultimate theory, it won’t tell us much about how the universe began. It can not predict the dimension of spacetime, the gauge group, or other parameters of the low energy effective theory. On the other hand, the theory will predict that the total energy density, will be exactly the critical density, though it won’ t determine how this energy is divided between conventional matter, and a cosmological constant, or quintessence. The theory will also predict a nearly scale free spectrum of fluctuations. But it won’t determine the amplitude. So to come back to the question with which I began this talk. Does string theory predict the state of the universe. The answer is that it does not. It allows a vast landscape of possible universes, in which we occupy an anthropically permitted location. But I feel we could have selected a better neighbourhood.”

Stephen Hawking, Cosmology from the Top Down, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, 29 May 2003 (pdf)

See also:

☞ Tim Maudlin, What Happened Before the Big Bang? The New Philosophy of Cosmology, The Atlantic, Jan 2012.

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Our sense of time is deeply entangled with memory

“If our’ sense of time is largely a cognitive illusion, then where does the illusion come from? (…)

According to David Eagleman, it’s all about memory, not turbo perception. “Normally, our memories are like sieves,” he says. “We’re not writing down most of what’s passing through our system.” Think about walking down a crowded street: You see a lot of faces, street signs, all kinds of stimuli. Most of this, though, never becomes a part of your memory. But if a car suddenly swerves and heads straight for you, your memory shifts gears. Now it’s writing down everything — every cloud, every piece of dirt, every little fleeting thought, anything that might be useful.

This is a deeply Proustian idea. It turns out that our sense of time is deeply entangled with memory, and that when we remember more – when we are sensitive to every madeleine and sip of limeflower tea – we can stretch time out, like a blanket. This suggests that the simplest way to extend our life, squeezing more experience out of this mortal coil, is to be more attentive, more sensitive to the everyday details of the world. The same logic should also apply to our vacations. If we want our time off to last longer, then we should skip the beach naps and instead cram our days full of new things, which we will notice and memorize.”

Jonah Lehrer, In Search of Time, Wired Science, August 30, 2010

We structure our experience of time around memories. (…)

Monotony collapses time; novelty unfolds it. You can exercise daily and eat healthily and live a long life, while experiencing a short one. If you spend your life sitting in a cubicle and passing papers, one day is bound to blend unmemorably into the next - and disappear. That’s why it’s so important to change routines regularly, and take vacations to exotic locales, and have as many new experiences as possible that can serve to anchor our memories. Creating new memories stretches out psychological time, and lengthens our perception of our lives. (…)

It is forgetting, not remembering, that is the essence of what makes us human. To make sense of the world, we must filter it. “To think,” Borges writes, “is to forget.”

Joshua Foer, American science journalist, Moonwalking with Einstein: The Art and Science of Remembering Everything, Penguin Press HC, New York, 2011
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A visualisation of the past light cone (at bottom), the present, and the future light cone in 2D space.
A Light cone is the path that a flash of light, emanating from a single event E (localized to a single point in space and a single moment in time) and traveling in all directions, would take through spacetime. Imagine the light confined to a two-dimensional plane, the light from the flash spreads out in a circle after the event E occurs—and when graphed the growing circle with the vertical axis of the graph representing time, the result is a cone, known as the future light cone. The past light cone behaves like the future light cone in reverse, a circle that contracts in radius at the speed of light until it converges to a point at the exact position and time of the event E. In reality, there are three space dimensions, so the light would actually form an expanding or contracting sphere in 3D space rather than a circle in 2D, and the light cone would actually be a four-dimensional shape.

A visualisation of the past light cone (at bottom), the present, and the future light cone in 2D space.

A Light cone is the path that a flash of light, emanating from a single event E (localized to a single point in space and a single moment in time) and traveling in all directions, would take through spacetime. Imagine the light confined to a two-dimensional plane, the light from the flash spreads out in a circle after the event E occurs—and when graphed the growing circle with the vertical axis of the graph representing time, the result is a cone, known as the future light cone. The past light cone behaves like the future light cone in reverse, a circle that contracts in radius at the speed of light until it converges to a point at the exact position and time of the event E. In reality, there are three space dimensions, so the light would actually form an expanding or contracting sphere in 3D space rather than a circle in 2D, and the light cone would actually be a four-dimensional shape.

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Diagram of the multiverse from What Is Time? One Physicist Hunts for the Ultimate Theory - interview with Sean Carroll, a senior research associate in the Department of Physics at the California Institute of Technology, Wired.com, February 26, 2010
"Sean Carroll: (…) I’m fitting in with a line of thought in modern cosmology that says that the observable universe is not all there is. It’s part of a bigger multiverse. The Big Bang was not the beginning.  And if that’s true, it changes the question you’re trying to ask. It’s not, “Why did the universe begin with low entropy?” It’s, “Why did part of the universe go through a phase with low entropy?” And that might be easier to answer.
Q: In this multiverse theory, you have a static universe in the middle. From that, smaller universes pop off and travel in different directions, or arrows of time. So does that mean that the universe at the center has no time?
Carroll: So that’s a distinction that is worth drawing. There’s different moments in the history of the universe and time tells you which moment you’re talking about. And then there’s the arrow of time, which give us the feeling of progress, the feeling of flowing or moving through time. So that static universe in the middle has time as a coordinate but there’s no arrow of time. There’s no future versus past, everything is equal to each other.
 So it’s a time that we don’t understand and can’t perceive?
Carroll: We can measure it, but you wouldn’t feel it. You wouldn’t experience it. Because objects like us wouldn’t exist in that environment. Because we depend on the arrow of time just for our existence.
Q: So then, what is time in that universe?
Carroll: Even in empty space, time and space still exist. Physicists have no problem answering the question of “If a tree falls in the woods and no one’s there to hear it, does it make a sound?” They say, “Yes! Of course it makes a sound!” Likewise, if time flows without entropy and there’s no one there to experience it, is there still time? Yes. There’s still time. It’s still part of the fundamental laws of nature even in that part of the universe. It’s just that events that happen in that empty universe don’t have causality, don’t have memory, don’t have progress and don’t have aging or metabolism or anything like that. It’s just random fluctuations.
Q: So if this universe in the middle is just sitting and nothing’s happening there, then how exactly are these universes with arrows of time popping off of it? Because that seems like a measurable event. (…)
So what happens to the arrow in places like a black hole or at high speeds where our perception of it changes?
Carroll: This goes back to relativity and Einstein. For anyone moving through spacetime, them and the clocks they bring along with them – including their biological clocks like their heart and their mental perceptions – no one ever feels time to be passing more quickly or more slowly. Or, at least, if you have accurate clocks with you, your clock always ticks one second per second. That’s true if you’re inside a black hole, here on Earth, in the middle of nowhere, it doesn’t matter. But what Einstein tells us is that path you take through space and time can dramatically affect the time that you feel elapsing.  The arrow of time is about a direction, but it’s not about a speed. The important thing is that there’s a consistent direction. That everywhere through space and time, this is the past and this is the future.”

Diagram of the multiverse from What Is Time? One Physicist Hunts for the Ultimate Theory - interview with Sean Carroll, a senior research associate in the Department of Physics at the California Institute of Technology, Wired.com, February 26, 2010

"Sean Carroll: (…) I’m fitting in with a line of thought in modern cosmology that says that the observable universe is not all there is. It’s part of a bigger multiverse. The Big Bang was not the beginning. And if that’s true, it changes the question you’re trying to ask. It’s not, “Why did the universe begin with low entropy?” It’s, “Why did part of the universe go through a phase with low entropy?” And that might be easier to answer.

Q: In this multiverse theory, you have a static universe in the middle. From that, smaller universes pop off and travel in different directions, or arrows of time. So does that mean that the universe at the center has no time?

Carroll: So that’s a distinction that is worth drawing. There’s different moments in the history of the universe and time tells you which moment you’re talking about. And then there’s the arrow of time, which give us the feeling of progress, the feeling of flowing or moving through time. So that static universe in the middle has time as a coordinate but there’s no arrow of time. There’s no future versus past, everything is equal to each other.

So it’s a time that we don’t understand and can’t perceive?

Carroll: We can measure it, but you wouldn’t feel it. You wouldn’t experience it. Because objects like us wouldn’t exist in that environment. Because we depend on the arrow of time just for our existence.

Q: So then, what is time in that universe?

Carroll: Even in empty space, time and space still exist. Physicists have no problem answering the question of “If a tree falls in the woods and no one’s there to hear it, does it make a sound?” They say, “Yes! Of course it makes a sound!” Likewise, if time flows without entropy and there’s no one there to experience it, is there still time? Yes. There’s still time. It’s still part of the fundamental laws of nature even in that part of the universe. It’s just that events that happen in that empty universe don’t have causality, don’t have memory, don’t have progress and don’t have aging or metabolism or anything like that. It’s just random fluctuations.

Q: So if this universe in the middle is just sitting and nothing’s happening there, then how exactly are these universes with arrows of time popping off of it? Because that seems like a measurable event. (…)

So what happens to the arrow in places like a black hole or at high speeds where our perception of it changes?

Carroll: This goes back to relativity and Einstein. For anyone moving through spacetime, them and the clocks they bring along with them – including their biological clocks like their heart and their mental perceptions – no one ever feels time to be passing more quickly or more slowly. Or, at least, if you have accurate clocks with you, your clock always ticks one second per second. That’s true if you’re inside a black hole, here on Earth, in the middle of nowhere, it doesn’t matter. But what Einstein tells us is that path you take through space and time can dramatically affect the time that you feel elapsing. The arrow of time is about a direction, but it’s not about a speed. The important thing is that there’s a consistent direction. That everywhere through space and time, this is the past and this is the future.

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The Big Bang
The Big Bang is the cosmological model of the initial conditions and subsequent development of the Universe that is supported by the most comprehensive and accurate explanations from current scientific evidence and observation. As used by cosmologists, the term Big Bang generally refers to the idea that the Universe has expanded from a primordial hot and dense initial condition at some finite time in the past (best available measurements in 2009 suggest that the initial conditions occurred around 13.3 to 13.9 billion years ago), and continues to expand to this day.

The Big Bang

The Big Bang is the cosmological model of the initial conditions and subsequent development of the Universe that is supported by the most comprehensive and accurate explanations from current scientific evidence and observation. As used by cosmologists, the term Big Bang generally refers to the idea that the Universe has expanded from a primordial hot and dense initial condition at some finite time in the past (best available measurements in 2009 suggest that the initial conditions occurred around 13.3 to 13.9 billion years ago), and continues to expand to this day.