Laws and Reality

Laws and Reality

I am going to be brief but broad. It is a plausible thesis that reality requires laws: nothing can exist and not be subject to natural law. This applies to the mind as well as the physical world. Laws make things what they are; you cannot detach the laws and expect the particulars to remain the same. You can’t have the same particulars existing in a possible world and yet the laws of nature are completely different. The same goes for natural kinds: the kinds of the actual world necessarily obey the laws (or similar laws) they actually obey. Particulars, kinds, and laws are inextricable. Lions can’t obey the laws of spiders (they wouldn’t be lions) and iron can’t obey the laws of rubber (it wouldn’t be iron). So, the physical world must obey some physical laws, even if not the ones we now accept; and similarly for the mental world. But it is a further question how strict these laws are, or must be: must they be strict and exceptionless or can they be non-strict and allow exceptions? It is difficult to accept that all the laws could be non-strict—some must be strict, though not all must be strict. The most reasonable position is that all sectors of reality must have both strict laws and non-strict laws. In addition, we may assume that they also have non-lawlike true generalizations (e.g., “All the coins in my pocket are dimes”). So, physical things must fall under strict laws, non-strict laws, and non-lawlike generalizations. Basic physics, folk physics, and coincidences.

Is the same thing true of the mind? Yes, it must be, because the mind also is a part of nature—a natural object. It would be widely agreed that the mind obeys non-strict psychological laws—such as the law that people tend to act on their desires. But does the mind also obey strict laws? Is there a basic psychology as there is a basic physics? That is not so clear. If it doesn’t, it must obey strict laws of some sort, by our earlier considerations. A reason to think the laws cannot be purely psychological is that the mind is always being affected by things outside of it—psychophysical causal connections. Let’s suppose this to be true: all purely psychological laws are non-strict. That doesn’t imply that the mind obeys no strict laws—those laws might be physical or psychophysical. The first alternative can be ruled out, because these would not be laws of the mind—just physical laws of associated physical things, such as the brain. So, the laws would have to be psychophysical, linking the brain to the mind presumably. Therefore, there are strict psychophysical laws. This doesn’t mean that all psychophysical laws must be strict; some no doubt are not strict. But some must be strict: there must be exceptionless laws connecting the mind to the physical world outside the mind, presumably the brain. This is a rather strong result: there are strict laws of nature connecting what happens in the brain with what happens in the mind. These laws coexist with non-strict psychophysical laws, perhaps underlying them in some way.

This opens up an intriguing possibility. Given that we don’t know of any strict psychophysical laws, or very few, there must be other laws, hitherto unknown, that connect mind and brain (or mind and body, or mind and world). There must be (strict) psychophysical laws that we don’t know. And if our present nomological knowledge of mind and brain is far from providing any strict laws, as seems likely, then the necessary strict psychophysical laws must be quite far removed from current knowledge. Let’s accept that proposition: then we can say that mind and brain must satisfy descriptions (have properties) not currently anticipated in our conceptual scheme. We have no idea of the strict laws that connect mind and brain, but such laws must exist. We thus obtain a kind of mysterianism from the assumption of the universality of strict laws (combined with their current absence in the psychophysical case). Even if we have an inkling of the required law in some cases, it is still true that every non-strict law presupposes the existence of a strict law, so there will be many cases of strict psychophysical laws that we don’t know. This would mean, for example, that intentional action must fall under strict psychophysical laws that we don’t know—or even know how to find. Ordinary belief-desire psychology only gives us non-strict laws, but these must point to other laws that are strict. But what might those be? Not laws of belief-desire psychology presumably, because they yield only non-strict laws. The strictness requirement leads to a rather startling admission of ignorance, if not mystery. Intuitively, desires never necessitate, so there must something else of a psychological nature that underlies desires—this thing being what the strict laws concern. The mind must be made of something other than beliefs and desires where action is concerned. Other types of psychophysical link would yield the same kind of conclusion given that we only have non-strict laws as things are (e.g., laws linking stimuli and percepts, or emotions and emotional reactions). It may equally be true that the brain must have states other than those currently postulated, in order to provide the needed psychophysical laws. The brain must be made of more than our present picture of it indicates. Strict laws need appropriate descriptions, but we don’t now possess such descriptions, so there must be descriptions we don’t know. The world is inherently law-governed, both strictly and non-strictly, so there has to be more to it than we suppose. And not just a little more but a lot more, because the gap is wide, the ignorance profound. In a word: laws imply mystery.[1]

[1] I am obviously using some of the terminology and apparatus that Davidson introduced in “Mental Events”.