Occasionalism

4. Occasionalism and immaterialism

Whether this argument provides effective support for occasionalism depends on whether occasionalism is itself a tenable view. It can be argued on both epistemological and metaphysical grounds that the material substance posited by occasionalists is redundant and should be eliminated, leading to a Berkeleyan immaterialism (see Berkeley, G. §§3, 6–7). Epistemologically, occasionalism holds that material substances make no causal contribution towards our perceptions of objects. Occasionalists hold, to be sure, that light waves (for example) travel from observed bodies to our eyes, that nerve impulses connect the eyes with the brain, and that consequent to this we experience visual images. But there is no real causal connection between any two of these stages; in particular, the visual images are not produced by the brain (or even by the immaterial mind), but rather by God ‘on the occasion’ of the brain’s being in an appropriate state. This means, however, that we have no direct evidence for the existence of the supposed intermediate stages in the process, and it is hard to avoid Berkeley’s conclusion that it would be simpler for God to omit them.

A similar conclusion can be reached through metaphysical considerations. Occasionalism holds that created substances make no active causal contribution to subsequent states of the world. But then the occasionalist is faced with the question of whether created substances are endowed with causal powers at all. If they are, then God must somehow intervene to prevent the powers from being exercised – and indeed, the provision to created things of powers that are never exercised and are not intended by God to be exercised would seem highly unreasonable. So the occasionalist must deny that created beings possess causal powers. But what, if anything, might created substances consist in, if they lack such powers entirely?

Apparently the occasionalist answer is that while created substances lack active powers they do possess some passive powers; hence al-Ghazali’s view of material beings as inert, and Malebranche’s willingness to attribute movability and impenetrability (but not active power) to material objects. So as Freddoso suggests, ‘God would supply all the active causal power in nature, while material substances would receive and channel God’s causal influence as patients’ (1988: 111). The difficulty with this is that the active/passive distinction, as we make it, cannot give occasionalism what it needs here. We do have some grip on the difference between an object’s acting on another or being acted upon by another. (In many cases this would coincide with the direction of energy transfer.) But the very same molecular structure which makes a billiard ball impenetrable by another billiard ball also enables it, under appropriate conditions, to propel the other billiard ball in a desired direction. The active/passive distinction just does not cut deep enough to play the role it is cast in by occasionalism. But if material substances have neither active nor passive powers, then it is difficult to see the point of their existing – indeed, it is difficult to see what could be meant by claiming that they exist.

The correct conclusion would seem to be that the logic of occasionalism leads to Berkeleyan immaterialism, and that it is in this form, if any, that it may be able to survive as a viable contemporary option. A more attractive option, though slightly more remote from classical occasionalism, can perhaps be found in certain anti-realist interpretations of natural science (see Scientific realism and antirealism). Though diverging from the letter of both occasionalism and Berkeleyanism, these anti-realist views are akin to them in spirit in their desire to uphold science as an empirical enterprise while avoiding the mechanistic materialism which threatens on a realistic interpretation of scientific theories.