Classical Theism: Background

Good metaphysical arguments don’t operate in a vacuum. They occur within a theoretical framework provided by a successful, time-tested research program. The oldest and most successful research program in metaphysics is that of the so-called perennial philosophy, beginning with Plato and Aristotle, extended by the Neo-Platonists, and developed in Western scholastic philosophy. At the core of this program is the distinction between two modes of being, potential and actual, along with a commitment to a strong principle of proportionate causation, that is, the principle that the greater the effect, the greater the cause must be. Many contemporary philosophers have defended this program (myself included).
 
Another important assumption of the perennial philosophy concerns the dependent nature of time. Time is not merely a static dimension within which events and states can be located. Such a Block Universe picture of time would leave us with many inexplicable data, including the irreversible direction of time and causation, the fixity of the past and the openness of the future, the basis of the Second Law of Thermodynamics and other irreversible laws, and our universal experience of the passage of time. Aristotle provides a much more satisfying account of time in Book III of his Physics: time is simply the measure of change. Change is the more fundamental phenomenon, and the distinctive characteristics of time are derivable from the nature of change.
 
This hypothesis requires that change itself not be given a real definition in terms of time. That is, we must reject Bertrand Russell’s At-At theory of change (Russell 1922, Lecture VI), according to which a thing x undergoes change just in case it has one feature at some time t1 and a contrary feature at some later time t2. Instead, we must define change as Aristotle does. A thing x is undergoing change just in case there is some feature F of such a kind that x has a potentiality for F-ness that is in some degree of partial actualization. This definition does not make any reference to moments of time or their temporal relations of earlier and later. However, it does entail that if some entity x is undergoing change with respect to F-ness, there must be earlier and later times of such a kind that x is progressively closer to F at the successively later moments of time. Partial actualization requires at least two distinct modes of being (i.e., instants of time), one in which x is (still) only potentially F, and another in which it is actually F. In fact, there must be an infinite number of such instances, each with a different degree of actuality of x’s F-ness, with the full actualization of x’s potential for F-ness occurring in exactly one of these. The direction of time is determined by the prior direction of change: if x’s potentiality for F-ness is partially actualized, and this partial actualization corresponds to a set of moments, then the later moments in that set must be ones in which x is closer to being F.
 
Now let’s add to this picture the assumption that all change must have a cause. Another word for ‘change’ in this context is ‘passion’. Let’s assume, then, that every passion has a corresponding action. On this picture, the action of the agent is the cause; the passion of the patient is the effect. Causation always involves two or more substances. Here we will also introduce a principle of proportionate causality. It is obvious, for example, that actual change or passion can only result from actual action, involving an actually existing agent and an actually possessed active power. A merely potential event cannot be the actual cause of any actual change. A merely potential agent cannot act.
 
If we were to abandon this principle of ontologically proportionate causality, we would have no explanation for the asymmetry and irreflexivity of causation. That is, we couldn’t explain why a given passion couldn’t be its own cause, promoting itself from mere potentiality to actuality. This would be tantamount to rejecting the causal principle altogether.

It is important to recognize that accepting this Aristotelian framework does not depend on deciding the A Theory/B Theory issue. In particular, it does not depend in any way on so radical a thesis as Presentism—the view that everything that is actual is actual at the present time. It is compatible with Aristotelianism that there be infinitely many different modes of actuality, one for each moment of time, past, present and future. All that is required  is the assumption that to effect a change that is actual in mode t, the agent must have a power that is actual in that same mode, i.e., at that same time.
 
This viewpoint would not be consistent with a non-Aristotelian version of the B Theory—one in which every event at every moment of time is actual in exactly the same way. On such a Block Universe model, there is no room for defining change as the actualization of a specific potential. Such a model, as J. M. E. McTaggart long ago noted, fails to take seriously the reality of change.