The previous post distinguished two very general models for explaining a phenomenon: mechanism, defined by the primary role it gives to causation; and agency, defined by the parallel primary role it gives to will or purpose. What was absent was a term that a fair number of people would view as a possible alternative to, and improvement over, both -- "holism". In this note I just want to say why it was left out -- why, in other words, I think it's not really an alternative, much less an improvement, to either.
The short answer is that holism is not actually an explanatory model as such at all, but rather a set of explanatory guidelines at best, and an avoidance of explanation altogether at worst. Like many "isms", holism comes in a range of flavors or versions, from what's usually called "weak" at one end of the spectrum to "strong" at the other end. In all versions, I think, we can distinguish two broad aspects or themes to holism: that the whole is greater than the sum of the parts, and that context or environment is important in understanding a system. Let's briefly look at both:
That the whole is greater than the sum of the parts:In weak or moderate versions of holism, this notion is certainly valid, but largely a truism -- any machine, after all, is greater than the simple sum of its parts in the obvious sense that the structure or relationship of the parts is a vital aspect of its functioning -- and understanding the mechanism of any phenomenon entails an understanding of how the parts interrelate. In its mild form, admittedly, this theme can sometimes provide useful advice when dealing with particularly subtle or complex phenomena, where the "whole" may not be immediately evident. But in its stronger versions, this idea is often taken to imply that the "whole" contains some mysterious extra quality or ingredient that is impervious to analysis, and this simply becomes a way of refusing or blocking explanation altogether.
That context matters:
This theme, in moderate versions of holism, is actually quite important -- the behavior of many systems is quite dependent upon the environment in which they're situated, and may change drastically if that context is changed. It may still, of course, be a reasonable strategy to try to gain as good an understanding as possible of the system in isolation (a simpler problem), while realizing that a full or real-world understanding will need to include the larger "whole" of which the system is a part. That said, however, this theme too is frequently taken to untenable extremes in the "stronger" or more mystical versions of holism, where it's used to assert that "everything is connected" and hence nothing can be studied, understood or explained in itself.
So: "holism" in its more moderate flavors can add a helpful perspective to an explanatory project, but hardly qualifies as an explanatory model in itself; and in its stronger flavors, it tends to become a means of opposing explanation as such (sometimes, perhaps, in an effort to protect a favored belief, or sometimes just in the service of mystery itself).