The project of science is largely about asking why things happen. We seek causal explanations: Why do planets follow elliptical orbits? Why does water become solid in cold temperatures?
Historically, this project has been largely reductionist in its approach. That is, scientists have generally taken the view that phenomena can be explained in terms of smaller components. We can understand how molecules behave by looking at their atoms; we can understand how atoms behave by looking at subatomic particles, etc. This program has been extremely productive: we can explain why oceans have tides and why prisms make rainbows. Because of this success, some people believe that science will eventually be able to explain everything this way. They argue that, if we can just understand matter at its tiniest level—quarks or whatever else is smaller than them—explanations for everything else will follow as a matter of course.
I encounter this extreme view not so much in academic papers, but moreso in casual conversations among people who want to ground their arguments in science. It seems to be a common "move" to argue that some concept is meaningless or illusory, because it can ultimately be reduced to the level of atoms, genes, or some other constituent entity. Jerry Coyne, for example, argues in a recent essay that free will does not exist, because our brains are composed of atoms that must obey the laws of physics.
I argue that this extreme reductionism does not make for convincing arguments, on two grounds. (I should pause to say that the ideas here are heavily influenced by many other thinkers—Stuart Kauffman in particular.) The first is that understanding the behavior of the parts of a system doesn't necessarily imply an understanding of the behavior of the whole. This is a result of chaos theory. It can be shown that most systems with many interacting parts are chaotic, meaning that even if one could measure the present behavior of each component to within arbitrary precision, this would not suffice to predict the system's behavior for more than a brief window of time. Any initial inaccuracies in measurement rapidly compound until all predictive power is lost. (This is the famous "butterfly effect": the future can be changed by a flap of a butterfly's wings.) Additionally, quantum effects add another source of indeterminacy to any physical system. Thus it is impossible, for example, to predict the advent of mantis shrimp or David Bowie by starting from the Big Bang and applying the laws of physics. These entities do not contradict the laws of physics, but they're not predicted by them either. (Okay, maybe Bowie contradicts the laws of physics just a little bit.)
The second ground—and the idea I most want to explore here—is the following:
Historically, this project has been largely reductionist in its approach. That is, scientists have generally taken the view that phenomena can be explained in terms of smaller components. We can understand how molecules behave by looking at their atoms; we can understand how atoms behave by looking at subatomic particles, etc. This program has been extremely productive: we can explain why oceans have tides and why prisms make rainbows. Because of this success, some people believe that science will eventually be able to explain everything this way. They argue that, if we can just understand matter at its tiniest level—quarks or whatever else is smaller than them—explanations for everything else will follow as a matter of course.
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| A postulated interior of the Duck of Vaucanson (1738-1739) by an American observer. SOURCE: Wikimedia Commons |
I argue that this extreme reductionism does not make for convincing arguments, on two grounds. (I should pause to say that the ideas here are heavily influenced by many other thinkers—Stuart Kauffman in particular.) The first is that understanding the behavior of the parts of a system doesn't necessarily imply an understanding of the behavior of the whole. This is a result of chaos theory. It can be shown that most systems with many interacting parts are chaotic, meaning that even if one could measure the present behavior of each component to within arbitrary precision, this would not suffice to predict the system's behavior for more than a brief window of time. Any initial inaccuracies in measurement rapidly compound until all predictive power is lost. (This is the famous "butterfly effect": the future can be changed by a flap of a butterfly's wings.) Additionally, quantum effects add another source of indeterminacy to any physical system. Thus it is impossible, for example, to predict the advent of mantis shrimp or David Bowie by starting from the Big Bang and applying the laws of physics. These entities do not contradict the laws of physics, but they're not predicted by them either. (Okay, maybe Bowie contradicts the laws of physics just a little bit.)
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| The laws of physics do not predict this hotness. |
The second ground—and the idea I most want to explore here—is the following:
Natural processes create new reasons for things to happen.
The prime example of this is evolution. Consider, for example, a bacterium swimming up a glucose gradient—perhaps the simplest goal-directed behavior in nature. The bacterium senses more glucose on one of its sides than the other, and swims in the direction of more glucose. What would we say is the reason for this behavior? One could investigate the physics and chemistry of the bacterium and identify mechanisms that cause it to move this way. But this does not explain the apparent agency in the bacterium's movement. The more satisfying explanation appeals to evolution: it moves toward greater sugar concentrations because evolution has provided it this mechanism to find food in order to reproduce.
Notice, however, that this explanation only makes sense on the level of the whole organism. The carbon and other atoms that comprise this bacterium do not act as if they had any goal. Only the bacterium as a whole appears to be goal-oriented. Thus reductionism completely fails to explain the bacterium's behavior. Evolution—a natural and spontaneous process—has created a new reason for something to happen. This reason applies to the whole organism, but not to its parts.
Once we accept that natural processes create new reasons for things to happen, many new questions arise. For instance, do different kinds of evolutionary processes create different reasons? Yes! It turns out that evolution in spatially dispersed populations can select for cooperative behaviors that would be disfavored if all individuals were mixed together. So the explanation "it behaves that way in order to help its neighbors" makes sense under some evolutionary conditions but not others.
We can also ask what other kinds of processes can create new causal explanations. Humans, for instance, engage in many activities that do not seem to be directly related to survival or reproduction; I would argue that this is due to a complex process in which our genes co-evolved with our cultures.
In short, nature can be creative. Not only can it create new objects and life forms, it can also create new meanings, in the sense of reasons for things to happen. These new meanings arise via naturally occurring processes that are consistent with—but not predicted by—the laws of physics. These processes can even generate new, higher-level processes, which then create additional new layers of meaning. If we, as scientists and as humans, want to understand why things happen, we must first understand the multiple, distinct ways that meaning and causality can arise.
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| Simulation of bacteria undergoing biased random walk toward a food source. SOURCE: http://www.mit.edu/~kardar/teaching/projects/chemotaxis%28AndreaSchmidt%29/finding_food.htm |
Once we accept that natural processes create new reasons for things to happen, many new questions arise. For instance, do different kinds of evolutionary processes create different reasons? Yes! It turns out that evolution in spatially dispersed populations can select for cooperative behaviors that would be disfavored if all individuals were mixed together. So the explanation "it behaves that way in order to help its neighbors" makes sense under some evolutionary conditions but not others.
We can also ask what other kinds of processes can create new causal explanations. Humans, for instance, engage in many activities that do not seem to be directly related to survival or reproduction; I would argue that this is due to a complex process in which our genes co-evolved with our cultures.
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| This man wants a slippery butt, but the individual cells that comprise him do not much care how slippery his butt is. SOURCE: Three Word Phrase by Ryan Pequin |