Reducibility and Emergence (False Intuitions of Science V)

In part 1 of this series of posts, I outlined a few intuitions that are often assumed as part of the scientific mind-set. In part 2, part 3, and part 4, I discussed the first three intuitions. In this post, I will discuss the final intuition:

* Physics serves as the ultimate science that all phenomena (including consciousness) can ultimately be explained in terms of and that all other sciences are reducible to

In previous posts, I discussed how physical models make abstractions of the world and in particular discard the subjective nature of actual entities. As a result, non-scientific inquiry into the world may be valuable, and claims that science can produce a complete description of the world are grossly overstated.

Even within the sciences, the scientific mind-set produces the intuition that everything ought to be reducible to physics. The higher sciences are therefore thought to be necessary only to abstract away the complexity that smaller-scale analysis would require. Each science builds upon the science studying the next smaller scope, so for example, (very loosely) psychology reduces to biology, which reduces to chemistry, which reduces to physics. Thus, the logical conclusion is that one's experience and behavior can ultimately be reduced to the configuration of atoms in one's body.

With the intuition of reducibility, all properties of complex or large-scale systems are thought to emerge from the physical properties of their components (and ultimately to the physical properties of their smallest components). The most egregious application of this intuition is with respect to human consciousness. The central problem in need of explanation is the hard problem of consciousness, which I would put thusly: how can subjective experience emerge from non-experiencing physical components?

It was just this problem that led me to reject my previously held intuitions of science. Most significantly, I read Daniel Dennett's Consciousness Explained and found it woefully inadequate. Ultimately, my answer to the question of how subjective experience arises from non-experiencing components was "it cannot". This is actually a similar conclusion to Dennett's, but whereas he discards the idea that we actually possess subjective experience (qualia), I rejected the idea that we are comprised of purely physical, non-experiencing components. In turn, I formed a crude panpsychist world-view and ultimately found refuge in the philosophy of Alfred North Whitehead.

I suspect Dennett's view of rejecting subjective experience is a minority one, but nevertheless most modern scientists and philosophers rely upon hand-waving emergence to explain consciousness: "we don't know how consciousness emerges from the brain, but somehow it does!" They provide other examples of emergence, such as a crystal from its molecules. But this appeal to physical emergence is ultimately inappropriate, as David Ray Griffin explains in The World-Knot (p. 64):

"The alleged emergence of subjectivity out of pure objectivity has been said to be analogous to examples of emergence that are different in kind. All of the unproblematic forms of emergence refer to externalistic features, features of things as perceived from without, features of objects for subjects. But the alleged emergence of experience is not simply one more example of such emergence. It involves instead the alleged emergence of an 'inside' from things that have only outsides. It does not involve the emergence of one more objective property for subjectivity to view, but the alleged emergence of subjectivity itself."

Another area where reduction and emergence are often misapplied is with respect to evolutionary biology "explaining" human psychology. For example, morality is explained by showing how it must be beneficial for the survival of the species. In fact, the existence of anything might be explained in terms of how it must be beneficial for the survival of its species. But even if benefit to the species is a requirement for a type of behavior or property to propagate, it does not explain how existence of that behavior or property is possible to begin with!

In both examples discussed above, there is some validity in correlating a type of phenomenon with its components or in terms of a lower science. Of course there is some relationship between one's subjective experience and the state of one's body (and particularly the brain). Of course the logic of natural selection plays a part in explaining how humans are the way we are. But extending these correlations and relationships to be a complete explanation of those phenomena would be not only a logical fallacy but, more significantly, a category mistake.