Are the Laws of Psychology Necessary?

Are the Laws of psychology Necessary?

There are laws of physics and laws of psychology, but are these laws of the same kind? Of course, they are about different things, but do they have the same modal status? Are they both nomologically necessary? The laws of physics are: they are universal and unalterable by human action. Everywhere you go the law of gravity holds; physical laws aren’t local. These laws are rightly called laws of nature—they characterize nature as a whole. They are as widespread as the universe itself (so far as we know). And no one can change them: nothing you can do will suspend the law of gravitation (or the electromagnetic laws, etc.).  The laws of physics are unconditional, ubiquitous, and immutable. They are not restricted to our solar system or even our galaxy. You can boldly go anywhere and they will be there waiting for you, always the same. But the same is not true of psychological laws: these laws are species-specific (in a broad sense of species). Some of them are species-specific in the usual sense of “species”, but if they apply more widely than this, they are still restricted to specific animal groups.  The law “Praise increases self-esteem” is presumably limited to humans, but other laws of psychology will be restricted to mammals or vertebrates or terrestrial life. Let’s take the example of memory laws, such as the frequency and recency laws: the more frequent or recent an experience the more it will be remembered. This law holds for many groups of animals, but does it hold for all? What about worms or wasps? Couldn’t there be a species that doesn’t exemplify these laws but still remembers things? It might obey the intensity law: the more intense the stimulus (louder, brighter) the more it will be remembered. What about laws relating emotion and memory—such as that strong emotion can enhance memory? That would hardly apply to an emotion-free organism that nevertheless remembers. Mr. Spock’s mind is free of emotion, so the laws governing it will not have an emotional component—it works by non-human psychological laws (he is not upset by insults). Thus, we have no trouble with the thought that in remote galaxies there might be minds that obey quite different laws from those with which we are familiar. Psychological laws are not going to be universal, invariant, built into nature; they are local, variable, parochial. They are more like anthropological laws, which vary with the society being considered: what holds of one society may not hold of another (science fiction is full of such societies). Psychological laws are not universal necessities.

Why is this? The answer, presumably, is that minds are adapted to specific types of environments and life-styles: what works for a mammal may not work for a mollusk. The laws of the octopus mind will not coincide with those of the bonobo mind. Just as an animal’s phenotype is shaped by its environment via natural selection, so the laws of that phenotype will be so shaped, including its mental phenotype. Psychological laws are evolved, selected, and modified over time. They are the children of selfish genes. Nothing like this is true of the laws of physics and chemistry. Artificial selection drives the point home: you could breed for certain psychological laws to obtain. Take the laws of conditioning, classical and operant: these hold for many animals, but we could intentionally breed them out and replace them with new laws. We could select for reproduction only dog minds that fail to acquire conditioned reflexes, or only pigeon minds that are bad at responding to positive reinforcement. We might get dogs that can never be made to salivate to bells, or pigeons that never learn to peck at levers that have supplied food pellets in the past. It all depends on genetics and brain wiring, which are manipulable. Likewise, we could breed for humans that don’t obey the frequency and recency laws of memory; or we could just interfere with the brain of humans to bring about this result. The laws depend on the mechanisms that depend on the selection history that depend on the environment. They are created by the local environment; they aren’t written into nature as such. Psychological laws are biology-dependent; they are contingent in that sense. Not even the laws of psychophysics are guaranteed to apply to all organisms capable of responding to a graded stimulus. Physiological laws are also species-specific, depending on the kind of body in question, and psychological laws are no different. The worm has a different physiology from the human and its mind (such as it is) is not operationally the same as a human mind—the governing laws are quite different.

Are there any psychological laws that apply universally? Does every animal act to fulfill its desires, say? This is certainly a very general law, but is it as universal as the law of gravity? Every physical body has mass (more or less) but not every organism has desires, though it will doubtless have biological needs. Some animals may be highly illogical, some models of rationality; some emotional, some clinical. It is hard to think of any psychological law that is written into nature—that is, intrinsically universal. Every mind obeys some set of psychological laws, but there is no set of psychological laws such that that set applies to all minds. Certainly, we can say that generally psychological laws are species-specific. The law of gravity (or the laws of motion in general) applies to every material body in the same way to the same degree, but psychological laws never apply identically to every organism with a mind. Bodies are nomologically homogeneous, but minds are not. Animal minds vary tremendously, and so do the laws governing them. Zoology isn’t like chemistry: the elements always behave in the same way—not so animals. Our Earth-centered zoology may have little application to the animals on other planets, but our chemistry will carry over nicely. Strange beasts, familiar chemicals. None of our species may exist on some distant planet, but surely our chemicals will be all present and correct (ditto our atoms).

This means that psychology will never be quite like physics. Physics envy is folly. This isn’t because there are no psychological laws, or that all such laws are ceteris paribus not strict, or that psychological laws can never be quantitative in the way physical laws are; it is because they lack universality. Even if they exist in plenty and are strict and quantitative, they would not have the range of physical laws—they would always be contingent and parochial. Nothing wrong with that—we should give up our craving for generality—but it is misguided to try to imitate the universality of the physical sciences. If you imagine what psychology will look like in the age of intergalactic travel, it will surely be a multi-faceted subject: there will be departments of human psychology, of Vulcan psychology, of Klingon psychology—not to mention the many animal species that need a psychology department of their own. A comprehensive Department of Psychology will be a vast undertaking, including many divisions and subdivisions; but the physics department will be a small operation employing relatively few professors, physics being a smaller field. Pan-galactic zoology is a vast area of study well beyond the capabilities of even the most learned man or woman, while pan-galactic chemistry is relatively confined and manageable. So, zoology and psychology will never have the range of physics and chemistry, but it will outdo them in manpower and variety. There will be many more doctorates in those fields than in the physical sciences. Indeed, physics and chemistry may long ago have come an end, everything having been discovered, while zoology and psychology are still in their infancy, with many living planets awaiting investigation. Physical science comes to a natural end while psychological science marches on.[1]

[1] One reaction to these reflections would be to announce that there are no genuine psychological laws, the emphasis indicating that genuine laws must be universal. The question is somewhat verbal, but one sees the point of such a declaration. A local law sounds like a contradiction. We might also consider the question of whether local psychological laws must be backed by non-local physical laws, thus deriving the conclusion that minds must ultimately be physical (cf. Davidson). We also have psycho-physical laws on the books: these combine the local with the universal, inviting the question of whether they are local or universal. It is certainly true that the physical laws were there first and that the psychological laws somehow rest on them (psychological laws are physically supervenient). These are topics for further study.