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Identity: who am I?
Every year 98% of the atoms of my body are replaced: how can I claim to be still the same person that I was last year, or, worse, ten years ago? What is (where lies) my identity? What is "my" relationship to the metabolism of my body?
Derek Parfit once proposed a thought problem: what happens to a person who is destroyed by a scanner in London and rebuilt cell by cell in New York by a replicator that has received infinitely detailed information from the scanner about the state of each single cell, including all of the person's memories? Is the person still the same person? Or did the person die in London? What makes a person such a person: bodily or psychological continuity? If a person's matter is replaced cell by cell with equivalent cells is the person still the same person? If a person's psychological state (memory, beliefs, emotions and everything) is replaced with an equivalent psychological state is the person still the same person? The question eventually asks what is "a life": is it a continuum of bodily states, whereby one grows from a child to an adult, or is it a continuum of psychological states? Or both? Or none?
The most obvious paradox is: how can reality be still the same as we grow up? Do two completely different brains see the same image when they are presented with the same object? If the brains are different, then the pattern of neural excitement created by seeing that object will be completely different in the two brains. How can two completely different brains yield the same image in the two brains? The logical conclusion is "no, the tree I see is not the tree you see, we just happen to refer to it the same way so it is not important what exactly we see when we look at it". But then how can we see the same image yesterday, today and tomorrow? Our brain changes all the time. Between my brain of when I was five years old and my brain of today there is probably nothing in common: every single cell has changed, connections have changed, the physical shape of the brain has changed. The same object causes a different pattern in my brain today than it did in my brain forty years ago. Those are two different brains, made of different cells, organized in different ways: the two patterns are physically different. Nonetheless, it appears to me that my toys still look the same. But they shouldn't: since my brain changed, and the pattern they generate has changed, what I see today should be a different image than the one I saw as a five-year old. How is it that I see the same thing even if I have a different brain?
This thought experiment almost seem to prove that "I" am not in my brain, that there is something external to the brain that does not change over time, that the brain simply performs computations of the image but the ultimate "feeling" of that image is due to a "soul" that is external to the brain and does not depend on cells or connections.
On the other hand, it is easy to see that what we see is not really what we think we see.
We have to keep in mind that when we recognize something as something, we rarely see/feel/hear/touch again exactly the same thing we already saw/felt/heard/touched before. I recognize somebody's face, but that face cannot possibly be exactly the same image I saw last time: beard may have grown, a pimple may have appeared, hair may have been trimmed, a tan may have darkened the skin, or, quite simply, that face may be at a different angle (looking up, looking down, turned half way). I recognize a song, but the truth is that the same song never "sounds" the same: louder, softer, different speakers, static, different echo in the room, different position of my era with respect to the speakers. I recognize that today the temperature is "cold", but if we measured the temperature to the tenth decimal digit it is unlikely that we would get the exact same number that I got the previous time I felt the same cold. What we "recognize" is obviously not a physical quantity: a image, a sound, a temperature never repeat themselves. What is it then that we recognize when we recognize a face, a song or a temperature? Broadly speaking, it is a concept.
We build concepts of our sensory experience, we store those concepts for future use, and we matched the stored concepts with any new concept. When we do this comparison, we try to find similarity and identity. If the two concepts are similar enough, we assume that they are identical, that they are the same thing. If they are not similar enough, but they are more similar than the average, then we can probably establish that they belong to a common super-concept (they are both faces, but not the same face; they are both songs, but not the same song; and so forth). We have a vast array of concepts which are organized in a hierarchy with many levels of generalization (your face to face of you and siblings to faces of that kind to face to ... to body part to ...). A sensory experience is somehow translated into a concept and that concept is matched with existing concepts and eventually located at some level of a hierarchy of concepts. If it is close enough to an existing concept of that hierarchy at that level, it is recognized as the same concept. Whatever the specific mechanism, it is obvious that what we recognize is not a physical quantity (distribution of colors, sound wave or temperature) but a concept, that somehow we build and compare with previously manufactured concepts.
Add to these considerations the fact that experience molds the brain: I am not only my genome, I am also the world around me. And I change all the time according to what is happening in the world. "I am" what the world is doing.
Identity is probably a concept. I have built over the years a concept of myself. My physical substance changes all the time, but, as long as it still matches my concept of myself, I still recognize it as myself.
The importance of being warm
When speculating about consciousness, identity and free will, it is important not to forget what bodies are and how they work.
Among the many bizarre features of living organisms, one is often overlooked: each living organism can live only within a very narrow range of temperature. Temperature is one of the most crucial survival factors.
Temperature also happens to be an important source of "identity": water and ice are made of the same atoms, it's the temperature that determines whether you are water or you are ice.
It's the temperature that determines whether your body is dead or alive, and it's the temperature that determines whether you are lying and shivering in bed or are playing soccer outside. Our identity does change with the temperature of our body (from no identity to "regular" identity to delirious identity).
Most of what our body does has nothing to do with writing poems or making scientific discoveries: it is about maintaining a stable temperature.
Some scientists (and Albert Einstein with them) have argued that consciousness must be fabricated by reality, that what we feel is simply an unavoidable consequence of the state of the universe, that we are simply machines programmed by the rest of the universe.
Other scientists believe the opposite, that consciousness fabricates reality, that we have the power to alter the course of the events. They believe in free will.
Do we think or are we thought?
The question, while popular, is misleading. The question is, in a sense, already an answer: the moment we separate the "I" and the body, we have subscribed to dualism, to the view that spirit and matter are separate and spirit can control matter.
A free will grounded in matter is not easy to picture because we tend to believe in an "I" external to our body that controls our body.
But, in a materialist scenario, the "I" is supposed to be only the expression of brain processes. If that is the case, then "free will" is not about the "I" making a decision: the "I" will simply reflect that decision. What makes the decision is the brain process.
This does not mean that free will can't exist. It just needs to be redefined: can a brain process occur that is not completely caused by other physical processes?
In a materialist scenario, free will does not require consciousness: consciousness is an aspect of the brain process that "thinks". The question is whether that brain process has free will.
If consciousness is indeed due to a physical process, if consciousness is ultimately material, does this preclude free will? For centuries we have considered free will an exclusive property of the soul, mainly because 1. we deemed the soul to be made of spirit and not matter, and 2. nothing in Physics allows for free will of matter.
If we now recognize that consciousness is a property of matter(possibly one that occurs only in some special form and configuration of matter, but nonetheless ultimately matter), the second statement must be examined carefully because the possibility of free will depends on its truth: if motion of matter is controlled only by deterministic laws, then free will is an illusion; if matter has a degree of control over its own motion, then free will is a fact.
The question is not whether we have free will, but whether the laws of our universe (i.e., Physics) allow for free will.
Why do living things do what they do?
The purposiveness of living organisms is simply a consequence of evolution by natural selection. Living organisms have a fundamental goal, survival, and have inherited a repertory of behaviors to achieve that goal. But the concept of "survival" can be better qualified as self-regulation.
The 19th-century French psychologist Claude Bernard "discovered" the self-regulating nature of living organisms. Bernard realized that each living organism is a system built to maintain a constant internal state in the face of changing external conditions. The regulation of this "milieu interieur" is life itself, because it is this stable state that gives the organism its independence from the environment, its identity. This is the dividing line that separates animate and inanimate matter: inanimate matter obeys Newton's laws of cause and effect, animate matter tends to maintain its state no matter what external forces are applied. Unlike objects, whose state is changed when a force is applied, the state of a living organism is not changed by an external force. The living organism, as long as it is alive, maintains its state constant.
The "purposeful" behavior of a living organism is the reaction to environmental forces: the organism needs to act in order to continuously restore its state. A body seems to "want", "intend", "desire" to maintain its internal state (either by eating, moving, sleeping, etc), a state that, ultimately, is a combination of chemical content and temperature. Living bodies appear to act purposedly, but they are simply reacting to the environment.
For Bernard "freedom" is independence from the environment. Control of the internal state allows a living organism to live in many different environments. The living organism is "free" in that is not a slave of its environment.
Bernard's idea of self-regulation extended to all living organisms. Humans are not the only ones to have "goals". Animate behavior "is" control of perception.
Will, not necessarily free: a materialistic view of free will
The problem with free will is that it does not fit too well with the scientific theories of the universe that have been developing over the last three centuries. While those theories are fairly accurate in predicting all the natural phenomena we deal with, they don't leave much room for free will. Particles behave the way they behave because of the fundamental laws of nature and because of what the other particles are doing; not because they can decide what to do. Since we are, ultimately, collections of particles, free will is an embarrassment of Physics.
On the other hand, a simple look at the behavior of even a fly seems to prove that free will is indeed a fact and is pervasive. Free will is a fundamental attribute of life. A robot that moved but only repeating a mechanical sequence of steps would not be considered "alive". Life has very much to do with unpredictability of behavior, not just with behavior. Or, better, behavior is behavior inasmuch as it is unpredictable to a degree; otherwise it is simply "motion".
Whether it is indeed "free" or not, "will" (the apparent ability of an ant to decide in which direction to move) appears to be an inherent feature of life, no matter how primitive life is. A theory of life that does not predict free will is not a good theory of life. Somehow, "free" will must be a product of the chemistry of life, at some very elementary level. In other words, obtaining the right chemical mix in the laboratory would not be enough: that mix must also exhibit the symptoms of free will.
The origin of free will, therefore, appears to be life itself.
Free will and randomness
Free will is often associated to randomness: a being has free will if it can perform "random" actions, as opposed to actions rigidly determined by the universal clockwork. In other words, free will can exist only if the laws of nature allow for some random solutions, solutions that can be arbitrarily chosen by our consciousness. If no randomness exists in nature, then every action (including our very conscious thoughts) is predetermined by a formula and free will cannot exist.
In their quest for the source of randomness in human free will, both neurophysiologists like John Eccles and physicists like Roger Penrose have proposed that quantum effects are responsible for creating randomness in the processes of the human brain. Whether chance and free will can be equated (free will is supposed to lead to rational and deterministic decisions, not random ones) and whether Quantum Theory is the only possible source of randomness is debatable.
Since we know that a lot of what goes on in the universe is indeed regulated by strict formulas, the hope for free will should rely not so much in randomness as in "fuzziness". It is unlikely that the laws of nature hide a completely random property; on the other hand, they could be "fuzzy", in that they may prescribe a behavior but with a broad range of possible degrees.
Free will and Physics
Whether we exercise it or not we do have free will: at every point in time we can choose what to do next.
Do animals also have free will? Or are they mechanisms, machines, that move according to formulas?
There is no evidence that at any point in time one can predict the next move of a chicken or an ant. No matter how simple and unconscious animals seem to be, their behavior is still largely unpredictable. You can guess what the chicken will want to do, but you can never be sure, and you can never guess the exact movements. There are infinite paths an ant can follow to go back to the nest and the one it will follow cannot be predicted. At every point of that path the ant can choose where to do next. Two ants will follow two different paths. Each ant seems to have its own personality.
Even the movement of mono-cellular organisms is unpredictable to some extent. No matter how small and simple the organism, a degree of free will seems to be there. Free will seems to be a property of life. What triggers the next move of bacteria, ants and chicken is not just a Newtonian formula. If they are machines, then these machines do not obey classical Physics. There is a degree of freedom that every living organism seems to enjoy. And it doesn't require a sophisticated brain. There is a degree of freedom that just shouldn't be there, if Newton was right.
If these are machines, they are machines that cannot be explained with our Mechanics because at every point in time there are many possible time evolutions and all seem to be possible, and none can be exactly predicted, pretty much like a quantum wave.
There is something missing in our Mechanics to account for free will of the machine.
Free will and choice
As usual, some misconception may arise from vague definitions. Is free will the consciousness of making one action out of so many possible ones, or is free will the ability to select one action out of so many possible ones? Why do we claim that a machine has no free will? Usually, because a machine can solve only the problems that we program it to solve. We, on the other hand, can solve novel problems in unpredictable situations (or, at least, give them a try). And that's because we can make actions that we have never done before and that nobody ever told us to do, whereas a machine can only do what it has been programmed to do.
This narrower definition of free will is interesting because it actually refers to the "architecture" and not really to the awareness or any other special property of human minds. Machines are built to solve specific problems in specific situations, simply because that is what humans are good at: building machines that solve specific problems in specific situations: we humans like to "design" a machine, to write the "specifications", etc. This is not the way nature built us. Nature built us on a different principle and it is no surprise that we behave differently. Since in nature we never know what the next problem and situation will be like, nature built us a "Darwinian" machines: our brains generate all the time a lot of possible actions and then pursue the ones that are "selected" by the environment (the specific problem and situation). Nature built us on a different principle than the one we use to build machines. The main difference between our mind and a machine is their archectures.
The lack of free will in machines is not a limit of machines: it is a limit of our mind. If we built a machine the same way nature builds its cognitive beings, i.e. with the same type of architecture, it would be a rather different machine, capable of generating a huge amount of random behaviors and then picking the one that best matches the current problem and situation. One can even envision a day when machines built with a "Darwinian" architecture (descendants of today's genetic algorithms and neural networks) will "out-free will" us, will exhibit even more free will than we do. After all, most of the times we simply obey orders (we obey publicity when we shop, we obey record labels when we sing a tune, we obey our mother's education all day long), whereas a machine would have no conditioning. And it may be able to generate a lot more alternatives than our brain does. Free will is simply a folk name for the Darwinian architecture of our mind.
The substance of our brain may not be the reason that we have free will and machines do not. It may be possible to build machines that also exhibit free will, even if they are built out of electronic components.
Do we think or are we thought?