I am presently teaching in a history subject dealing with ideas of nature, and I notice that the historians we are using often refer to a distinction between reductionism and holism. The former is the Bad Old Science (“we murder to dissect”) and the latter is the New Improved Science. This is something often stated as if the issue were obviously resolvable. And it is, in my view, a complete myth.
In biological science, people often suggest that reductionism is more than a mistake: it is in fact a morally dangerous position. Genetic reductionism is supposed to be the explanation of everything including behaviour in terms of genes. Many people have attacked it, including critics of sociobiology. And it must be said that genes function as a magic molecule in many people’s minds. But the problem is not that we give reductionist accounts of traits, but that we do so in terms of single genes. The error here is single cause explanations, not that we look for the properties of causal parts.
To reduce a domain to another, in this case behaviour to biology, is a virtue in science. Nearly all progress in biology has been made by identifying what causes observed properties of organisms and ecologies in terms of the parts of the systems being investigated. Cell theory in the 19th century, genetics in the 20th, and biochemistry throughout have shown us why organisms develop, react and adapt the way they do. The problem is not that we look for explanations in the parts of organisms, but that we do it hamfistedly.
Reductionism is supposed to look only at the parts, according to proponents of “holism”, when according to them we should look at the entire system and how it interacts. But I am hard pressed to find any reductionist who ever denied this. Instead we get methodological decisions to break systems into parts for the purposes of tractability. You simply cannot identify all the variables in a complex system, so scientists in general will attempt to model systems in ways that deal with a few aspects of the system, in order to see how much can be explained that way.
Reductionists believe several things: one of the more important is that the behaviour of a whole is explicable in terms of the properties of the parts that comprise it. Without this we would not have physics, chemistry, cell biology, or any other general science. But focusing on the properties of the parts has never made sense unless we consider how the parts interact. If you know that a cell produces a protein, to understand how it functions in the organism and its environment, you need to consider how that protein is distributed, and how other cells take it up and process it.
Likewise, in general, a reductionist account has to consider the interactions of the parts with each other. The properties of a single electron, for example, can be stated on their own, but how electrons interact with other subatomic particles depends on the properties of those particles, and so a “holistic” approach is implicit in the modelling of the electron itself.
So I get very tired of the general charge that reductionism is unable to understand the system-level properties of the parts. This is simply a rhetorical trick.
I gave my view of “pizza reductionism” before.