Tag Archives: models

Oops…One more thing!

After writing thirteen essays about space, I completely forgot to wrap up the whole discussion with some thoughts about the Big Picture! If you follow the links in this essay you will come to the essay where I explained the idea in more detail!

Why did I start these essays with so much talk about brain research? Well, it is the brain, after all, that tries to create ideas about what you are seeing based on what the senses are telling it. The crazy thing is that what the brain does with sensory information is pretty bizarre when you follow the stimuli all the way to consciousness. In fact, when you look at all the synaptic connections in the brain, only a small number have anything to do with sensory inputs. It’s as though you could literally pluck the brain out of the body and it would hardly realize it needed sensory information to keep it happy. It spends most of its time ‘taking’ to itself.

The whole idea of space really seems to be a means of representing the world to the brain to help it sort out the rules it needs to survive and reproduce. The most important rule is that of cause-and-effect or ‘If A happens then B will follow’. This also forms the hardcore basis of logic and mathematical reasoning!
But scientifically, we know that space and time are not just some illusion because objectively they seem to be the very hard currency through which the universe represents sensory stimuli to us. How we place ourselves in space and time is an interesting issue in itself. We can use our logic and observations to work out the many rules that the universe runs by that involve the free parameters of time and space. But when we take a deep dive into how our brains work and interfaces with the world outside our synapses, we come across something amazing.

The brain needs to keep track of what is inside the body, called the Self, and what is outside the body. If it can’t do this infallibly, it cannot keep track of what factors are controlling its survival, and what factors are solely related to its internal world of thoughts, feelings, and imaginary scenarios. This cannot be just a feature of human brains, but has to also be something that many other creatures also have at some rudimentary level so that they too can function in the external world with its many hazards. In our case, this brain feature is present as an actual physical area in the cerebral cortex. When it is active and stimulated, we have a clear and distinct perception of our body and its relation to space. We can use this to control our muscles, orient ourselves properly in space, walk and perform many other skills that require a keen perception of this outside world. Amazingly, when you remove the activity in this area through drugs or meditation, you can no longer locate yourself in space and this leads to the feeling that your body is ‘one’ with the world, your Self has vanished, and in other cases you experience the complete dislocation of the Self from the body, which you experience as Out of Body travel.

What does this have to do with space in the real world? Well, over millions of years of evolution, we have made up many rules about space and how to operate within it, but then Einstein gave us relativity, and this showed that space and time are much more plastic than any of the rules we internalized over the millennia. But it is the rules and concepts of relativity that make up our external world, not the approximate ‘common sense’ ideas we all carry around with us. Our internal rules about space and time were never designed to give us an accurate internal portrayal of moving near the speed of light, or functioning in regions of the outside world close to large masses that distort space.

But now that we have a scientific way of coming up with even more rules about space and time, we discover that our own logical reasoning wants to paint an even larger picture of what is going on and is happy to do so without bothering too much with actual (sensory) data. We have developed for other reasons a sense of artistry, beauty and aesthetics that, when applied to mathematics and physics, has taken us into the realm of unifying our rules about the outside world so that there are fewer and fewer of them. This passion for simplification and unification has led to many discoveries about the outside world that, miraculously, can be verified to be actual objective facts of this world.

Along this road to simplifying physics, even the foundations of space and time become players in the scenery rather than aloof partners on a stage. This is what we are struggling with today in physics. If you make space and time players in the play, the stage itself vanishes and has to somehow be re-created through the actions of the actors themselves .THAT is what quantum gravity hopes to do, whether you call the mathematics Loop Quantum Gravity or String Theory. This also leads to one of the most challenging concepts in all of physics…and philosophy.

What are we to make of the ingredients that come together to create our sense of space and time in the first place? Are these ingredients, themselves, beyond space and time, just as the parts of a chain mail vest are vastly different than the vest that they create through their linkages? And what is the arena in which these parts connect together to create space and time?

These questions are the ones I have spent my entire adult life trying to comprehend and share with non-scientists, and they lead straight into the arms of the concept of emergent structures: The idea that elements of nature come together in ways that create new objects that have no resemblance to the ingredients, such as evolution emerging from chemistry, or mind emerging from elementary synaptic discharges. Apparently, time and space may emerge from ingredients still more primitive, that may have nothing to do with either time or space!

You have to admit, these ideas certainly make for interesting stories at the campfire!

Check back here on Monday, December 26 for the start of a new series of blogs on diverse topics!

Is Space Real?

I take a walk to the store and can’t help but feel I am moving through something that is more than the atmosphere that rushes by my face as I go. The air itself is contained within the boundaries of the space through which I pass. If I were an astronaut in the vacuum of outer space, I would still have the sense that my motion was through a pre-existing, empty framework of 3-dimensions. Even if I were blind and confined to a wheelchair, I could still have the impression through muscular exertion that I was moving through space to get from my kitchen to my living room ‘over there’. But what is space as a physical thing? Of all the phenomena, forces and particles we study, each is something concrete though generally invisible: a field; a wave; a particle. But space, itself, seems to be none of these. WTF!

Spider web covered with dew drops

Way back in the early 1700s, Sir Isaac Newton proposed that space was an ineffable, eternal framework through which matter passed. It had an absolute and immutable nature. Its geometry pre-existed the matter that occupied it and was not the least bit affected by matter. A clever set of experiments in the 20th century finally demonstrated rather conclusively that there is no pre-existing Newtonian space or geometry ‘beneath’ our physical world. There is no absolute framework of coordinates within which our world is embedded. What had happened was that Albert Einstein developed a new way of thinking about space that essentially denied its existence!

Albert Einstein’s relativity revolution completely overturned our technical understanding of space and showed that the entire concept of dimensional space was something of a myth. In his famous quote he stressed that We entirely shun the vague word ‘space’ of which we must honestly acknowledge we cannot form the slightest conception. In the relativistic world we live in, space has no independent existence. “…[prior-geometry] is built on the a priori, Euclidean [space], the belief in which amounts to something like a superstition“. So what could possibly be a better way of thinking about space than the enormously compelling idea that each of us carries around in our brains, that space is some kind of stage upon which we move?

To understand what Einstein was getting at, you have to completely do away with the idea that space ‘is there’ and we move upon it or through it. Instead, relativity is all about the geometry created by the histories (worldlines) of particles as they move through time. The only real ‘thing’ is the collection of events along each particle’s history. If enough particles are involved, the histories are so numerous they seem like a continuous space. But it is the properties of the events along each history that determine the over-all geometry of the whole shebang and the property we call ‘dimension’, not the other way around.

This figure is an example where the wires (analogous to worldlines) are defining the shape and contours of a dimensional shape. There is nothing about the background (black) space that determines how they bend and curve. In fact, with a bit of mathematics you could specify everything you need to know about the surface of this shape and from the mathematics tell what the shape is, and how many dimensions are required to specify it!

Princeton University physicist Robert Dicke expressed it this way, “The collision between two particles can be used as a definition of a point in [space]…If particles were present in large numbers…collisions could be so numerous as to define an almost continuous trajectory…The empty background of space, of which ones knowledge is only subjective, imposes no dynamical conditions on matter.”

What this means is that so long as a point in space is not occupied by some physical event such as the interaction point of a photon and an electron, it has no effect on a physical process ( a worldline) and is not even observable. It is a mathematical ‘ghost’ that has no effect on matter at all. The interstitial space between the events is simply not there so far as the physical world based upon worldlines is concerned. It is not detectable even by the most sophisticated technology, or any inventions to come. It does not even supply something as basic as the ‘dimension’ for the physical world!

We should also be mindful of another comment by Einstein that “…time and space are modes by which we think and not conditions in which we live“. They are free creations of the human mind, to use one of Einstein’s own expressions. By the way, the 18th century philosopher Immanuel Kant also called the idea of ‘space’ an example of a priori knowledge that we are born with to sort out the world, but it is not necessarily a real aspect of the world outside our senses.

Like a spider web, individual and numerous events along a worldline define the worldline’s shape, yet like the spider web, this web can be thought of as embedded in a larger domain of mathematically-possible events that could represent physical events…but don’t. The distinction between these two kinds of points is what Einstein’s revolutionary idea of relativity provided physicists, and is the mainstay of all successful physical theories since the 1920s. Without it, your GPS-enabled cell phones would not work!

So what are these events? Simply put, according to Physicist Lee Smolin, they are exchanges of information, which are also the interaction points between one particle’s worldline and another particle’s world line. If you think at the atomic level, each time a particle of light interacts with (collides or is emitted by) an electron it generates an event. These events are so numerous the electron’s worldline looks like a continuous line with no gaps between the events. So the shape of one worldline, what we call its history, is a product of innumerable interactions over time with the worldlines of all other objects (photons etc) to which it can be in cause-and-effect contact.

Even though this new idea of space being a myth has gained enormous validity among physicists over the last century, and I can easily speak the language of relativity to describe it, personally, my mind has a hard time really understanding it all. I also use the mathematical theory of quantum mechanics to make phenomenally accurate predictions, but no Physicist really understands why it works, or what it really means.

Next time I want to examine how the history of a particle is more important than the concept of space in Einstein’s relativity, and how this explains the seeming rigidity of the world you perceive and operate within.

Check back here on Thursday, December 15 for the next installment!

Seeing with Mathematics

Our brain uses sensory data to sift for patterns in space and time that help us create a mental model of the world through which we can navigate and stay alive. At some point, this model of the external world becomes our basis for thinking symbolically and mathematically about it.

Mathematics is an amazingly detailed, concise and accurate way of examining the world to state the logical relationships we find there, but many physicists and mathematicians have been astonished about why this is the case. The physicist Eugene Wigner wrote an article about this in 1960 titled ‘The Unreasonable Effectiveness of Mathematics in the Natural Sciences’. In fact, since the enormous successes of Sir Isaac Newton in mathematically explaining a host of physical phenomena, physicists now accept that mathematics actually serves as a microscope (or telescope!) for describing things and hidden relationships we cannot directly experience. This amazing ability for describing relationships in the world (both real and imagined!) presents us with a new problem.

parabola

Mathematics is a symbolic way of describing patterns our world, and sometimes these symbolically-defined descriptions actually look like the things we are studying. For example, the path of a football is a parabola, but the equation representing its path, y(x), is also that of a parabolic curve drawn on a piece of paper. But what happens when the mathematical description takes you to places where you cannot see or confirm the shape of the object?

Mathematics is a tool for understanding the world and symbolically stating its many logical interconnections, but the tool can sometimes be mistaken for the thing itself. Here is a very important example that comes up again and again when physicists try to ‘popularize’ science.

In the late-1940s, physicist Richard Feynman created a new kind of mathematics for making very precise calculations about how light (photons) and charged particles (such as electrons) behave. His famous ‘Feynman Diagrams’ like the one below, are very suggestive of particles moving in space, colliding, and emitting light. This diagram, with time flowing from left to right, shows a quark colliding with an anti-quark, which generates a photon that eventually produces an electron and anti-electron pair.

feynman_qqgamee1

The problem is that this is not at all a ‘photograph’ of what is actually happening. Instead, this is a tool used for setting up the problem and cranking through the calculation. Nothing more. It is a purely symbolic representation of the actual world! You are not supposed to look at it and say that for the solid lines, ‘particles are like billiard balls moving on a table top’ or that the photon of light they exchange is a ‘wiggly wave traveling through space’. What these objects are in themselves is completely hidden behind this diagram. This is a perfect example of what philosopher Immanuel Kant was talking about back in the 1700s. He said that there is a behind-the-scenes world of noumena where the things-in-themselves (ding-an-sich) exist, but our senses and observations can never really access them directly. The Feynman diagram lets us predict with enormous precision how particles will interact across space and time, but hides completely from view what these particles actually look like.

Another example of how math lets us ‘see’ the world we cannot directly access is the answer to the simple question: What does an electron actually look like?

Since the 1800’s, electricity increasingly runs our civilization, and electricity is merely a measure of the flow of electrons through space inside a wire. Each of us thinks of electrons as tiny, invisible spheres like microscopic marbles that roll through our wires wicked fast, but this is an example of where the human brain has created a cartoon version of reality based upon our ‘common sense’ ideas about microscopic particles of matter. In both physics and mathematics, which are based upon a variety of observations of how electrons behave, it is quite clear that electrons can be thought of as both localized particles and distributed waves that carry the two qualities we call mass and charge. They emit electric fields, but if you try to stuff their properties inside a tiny sphere, that sphere would explode instantly. So it really does not behave like an ordinary kind of particle at all. Also, electrons travel through space as matter waves and so cannot be localized into discrete sphere-like particles. This is seen in the famous Double Slit experiment where electrons produce distinct wave-like interference patterns.

electronwave

So the bottom line is that we have two completely independent, mathematical ways of visualizing what an electron looks like, particles and matter waves, and each can facilitate highly accurate calculations about how electrons interact, but the two images (particle and wave – localized versus distributed in space) are incompatible with each other, and so we cannot form a single, consistent impression of what an electron looks like.

Next time we will have a look at  Einstein and his ideas about relativity, which completely revolutionized our common-sense understanding of space created by the brain over millions of years of evolution.

Check back here on Tuesday, December 13 for the next installment!

Rules-of-thumb

There are at least two basic ways that we create associations. The first is associations in space. The second is associations in time.

Associations in space include recognizing static objects like chairs, trees, cars and people. The reason this works so well is that we live in a world filled with many different kinds of more-or-less fixed objects so that two or more people can agree they have similar attributes.

Associations in time include musical tunes and sounds, or associating one thing (cause) with another thing in the future (effect). For many of these dynamic associations like music, two people with normal hearing senses hear the same sequence of notes in time and can agree that what they heard was a portion of a familiar song, which they may independently be able to name if they have heard it before and made the appropriate associations in memory. But your exact associations related to the song will be different than mine because I associate songs with episodes in my life that you do not also share. Remember, the brain tags everything with patterns of associations unique to the individual.

The human brain is adept at pattern recognition. It can dissect its sensory information and see patterns in space and time that it can then associate with abstract categories such as a chair or a bird, and even specific sub-categories of these if it has been adequately trained (at school, or by reading a book on ornithology!). An upside-down chair seen in the remote distance is recognized as a chair no matter what its orientation in the visual field. A garbled song heard on an iPhone in a loud concert hall, or a particular conversation between two people in a noisy crowd, can also be detected as a pattern in time and recognized. The figure shows some of the brain connection pathways identified in the Human Connectome Project that help to interpret sensory data as patterns in space and time.

brainmapping

Patterns in space let us recognize the many different kinds of objects that fill our world. In the association cortex, once these identifications have been made, they are also sent on to the language centers where they are tagged with words that can be spoken or read. Once this step happens, two individuals can have a meaningful conversation about the world beyond their bodies that the senses can detect. Of course when both people say they have a specific category of objects called Siamese cats, they are most certainly associating that name with slightly different set of events and qualities corresponding to their cat’s personalities , fur patterns, etc..

The next step is even more interesting.

Just as the brain generalizes a collection of associations in space to define the concept of ‘cat’, it can detect patterns in time in the outside world and begin to see how one event leads to another as a rule-of-thumb or a law of nature. If I drop a stone off a tall cliff, it will fall downwards to the valley below. If the sun rises and sets today, it will do so again tomorrow. There are many such patterns of events in time that reoccur with such regularity that they form their own category-in-time much as ‘cat’ and ‘chair’ did in the space context. ‘If I visit a waterhole with lots of animals, there is a good chance that tigers or lions may also be present’. More recently, ‘If I stick my finger in an unprotected electrical outlet, I will probably be electrocuted!’. This perception of relationships is one of cause-and-effect. It has been studied by neurophysiologists, and is due to stimulation of part of the cerebellum and the right hippocampus. These brain regions are both involved with processing durations in time.

Over the centuries and millennia, the patterns in time we have been able to discern about the outside world have become so numerous  we have to write them down in books, and also put our children through longer and longer training periods to master them. This also tells us something very basic about our world.

Instead of being a random collection of events, our physical world contains a basic collection of rules that follow a ‘logical’ If A happens then B happens pattern in time. Physicists call these relationships ‘laws’ and their particular patterns in time and space can be discerned from measurements and observations made of phenomena in the world outside our brains. The brain can also work with these laws symbolically and logically, not by describing them through the usual language centers of the brain, but through a parallel set of centers that make us adept at mathematical reasoning.

In my next blog, I will discuss how mathematics and logic are intertwined and help us think symbolically about our world.

Check back here on Friday, December 9 for the next installment!

Space, Time, and Causality in the Human Brain
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4008651/

A Stroke of Insight

Once the firehose of sensory information reaches the brain, a bewildering process of making sense of this data begins. The objective is to create an accurate internal model of the world that you can base your next decisions upon. To do this, all of the many bits of data flowing along the sensory neurons have to be knitted together somehow. Thanks to the unfortunate circumstances of minor strokes, brain researchers have been able to track down many of the important steps in this information processing.

brainspecial

You might have heard of the experiences of limb amputees who, for a time, experience the ‘phantom limb’ effect. The neurons having been severed still report back to the brain that their stimulation means the limb still exists, and for a period of time the amputee has to deal with the ghost limb that is not really there. In another bizarre situation, a stroke victim has a perfect understanding that their left arm belongs to them, but insists that their right arm belongs to a relative living 1000 miles away. This malady is called asomatognosia by neurophysiologists.

From many studies of how pinpoint strokes affect brain function, neuroanatomists have identified specific regions of the brain that allow us to integrate our sensory information and create a coherent model of the outside world as it exists in space and time. The first thing the brain has to do is to have a ‘sense’ of its own body and how it is located in space. It also has to identify this ‘self’ as being different from that of other people. If it cannot do this accurately, it cannot decide how to move in space, anticipate the consequences of that movement, or how to anticipate and empathize with the actions of other people. Nearly all of this activity seems to be relegated to a single area in the brain.

The temporoparietal junction (TPJ) takes information from the limbic system (emotional state) and the thalamus (memory) and combines it with information from the visual, hearing and internal body sensory systems to create an integrated internal model of where your body is located in space. The TPJ has left and right ‘lobes’ that control your ability to pay attention (right) and to anticipate other people’s emotions and desires (left). Patients with schizophrenia have abnormal levels of stimulation in the TPJ and cannot discern the intentions of other people. Stimulation of the right TPJ by placing electrodes in unesthetized patients leads to out-of-body experiences, schizophrenic behavior, and the phantom limb effect. The right TPJ tries to create a coherent body image from many different, and sometimes contradictory sensory inputs. When this process breaks down because the contradictory information is too strong to inhibit or ignore, you experience that you actually have two distinct bodies in space. This seems to be the direct, neural basis for out-of-body experiences.

But there is an even stranger brain region whose stimulation leads to an error in deciding where the body and self ends in space, and where the outside world begins.

The posterior cingulate body plays a huge role in self-location and body ownership. What this means is that we experience our body as having a definite location in space, and that this location is where you, the ‘Self’ is located. Strokes in this region cause asomatognosia patients not to recognize a limb as belonging to them. But you don’t have to be a stroke victim to experience this dislocation of body and self.

If you sit at a table facing a barrier that lets you see an artificial, life like right hand but not your real right hand, and you rhythmically stroke the real hand, eventually your brain gets fooled into believing that the artificial right hand is actually yours. If someone suddenly stabs the artificial hand, you will actually jump reflexively as though, for just an instant, the brain got confused about which was your real right hand being attacked!

The Posterior Superior Parietal Lobule gives us a sense of the boundary between our physical body and the rest of the world. When activity in this brain region is reduced, the individual seems to lose a sense of where their body ends and the rest of the world begins. The feeling is one of having ‘merged with the universe’ and your body is in some way infinite. Mindfulness practices such as meditation can modify the stimulation of this region and give the practitioner exactly this dramatic experience.

So you see, once sensory data gets to the brain, it is in for an amazing ride through many brain regions that help us build up the person or self that we feel we are through space and time.

By the way, for a fascinating introduction to these topics, read V.S. Ramachandran and Sandra Blakeslee’s book ‘Phantoms in the Brain: Probing the mysteries of the human mind’

Here is an interesting 2013 research paper in the journal Frontiers in Psychology ‘Alterations in the sense of time, space, and body in the mindfulness-trained brain: a neurophenomenologically-guided MEG study’ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3847819/

The connection between meditation and brain region function and stimulation is covered in this article: Mindfulness Practices and Meditation. https://neurowiki2012.wikispaces.com/Mindfulness+Practices+and+Meditation

But now let’s consider how the brain actually makes its models.

Check back here on Friday, December 2 for the next installment!