There are two seemingly contradictory views about the mind:

  1. Mental processes are fundamentally independent of their physical instantiation. For example, there is a traditional view that reasoning and logic are essential features of the mind. Now consider the argument that says that from A → B and B → C we can always conclude that A → C. This argument seems independent of the laws of physics; in some other alternate universe where gravity points upwards we might reasonable expect that the previous argument holds.

  2. Mental processes are completely determined by the laws of nature. We are biological beings and so everything about us including our capacity for reasoning is ultimately determined by physics. Even the rules of logic such as “If A → B and B → C then A → C” are ultimately consequences of the kinds of creatures we are.

The debate doesn’t go away even if we accept that the mind must be naturalized in some manner or the other. A subtle version of the above paradox arises in the “brain-in-a-vat” versus “the embodied mind” debate. Does the brain in a vat have the same mental capacities as a fully embodied being? Even if the mind is a natural entity, is it entirely in the brain or is it intrinsically tied to bodily capacities? Both intuitions seem to have validity; disabled people demonstrably have the same capacities as we do, but on the other hand it seems obvious that our minds evolved to respond to the pressures of surviving in the physical world.

These paradoxes arise from the fact that 1 and 2 are two completely different intuitions about mental phenomena. I believe that both are partial truths. We are part of nature and nature is undivided so there must a naturalistic theory of logic. On the other hand, what we mean by nature itself might have to change in order for us to incorporate logic into physics. Like cups and tables, thoughts and reasons also have a shape, but we need to rethink what we mean by “shape.” This is normal for science; we now think of gravity as well as mechanical impulses as forces, but one involves physical contact while the other operates at a distance. Action at a distance was a major problem for physicists who insisted that forces have to involve physical contact. Similarly, if we agree that the concept of shape need not be restricted to what we see with our eyes we will have a better idea of how to calculate the shape of thought. There are regularities that bind all these shapes together into a complex; our goal is to understand these regularities and the complex that emerges from them.

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