In Thales to Dewey, Gordon Clark provides a fairly detailed analysis of the basics of Aristotle’s system of thought. These basics are still debated today because they don’t only apply to Aristotelianism. Concepts such as definition, substance, unity, individuation, motion, space, time, etc. are ideas used by almost everybody. However, they can be quite difficult to understand and the consequences of false beliefs about these issues can be far-reaching. Moreover, one of the first things that a theology-enthusiast may notice when learning about Aristotle is that many theologians of history employed the same technical terminology as Aristotle. Therefore, an understanding of the Aristotelian background of terms such as substance, quality, nature, person, individual, numerical unity, subsistence, essence, generation, etc, can shed light on historical theology.
Around the middle of Clark’s explosion of Aristotle’s The Physics, he begins to discuss motion. Motion is the phenomenon that underlies all physics and all change. The principle of motion is nature. By nature, a stone dropped into the lake moves to the bottom and stops when it implants itself in the mud. The selection below is from Clark’s explanation of Aristotle’s definition of motion. All material is taken from P. 107 to 108 in Thales to Dewey.
Since nature is defined as a principle of motion, it is necessary to understand the meaning of motion in order to understand nature. Eventually Aristotle classifies change into types: generation and corruption; qualitative, or, in modern terms, chemical change; quantitative change, as growth and decay; and motion through space. All these are discussed at greater length than can be afforded here. Then, too, it is necessary to discuss continuum, infinity, place, void, and time, for these terms must be used in the explanation. But, first, motion must be defined.
Now the stage is set for a discussion of the definition of motion.
In the section on Logic the solution of the paradox of learning as presented in the Meno depended on the distinction between actual knowledge and potential knowledge. Also, in the section on the Law of Contradiction, the problem of the coexistence of contraries was solved by the same distinction. These concepts of actuality and potentiality are basic in Aristotle’s thought, and here they are necessary for the definition of motion.
Just as learning was defined in terms of actuality and potentiality, now motion will be defined in these terms.
But potentiality and actuality cannot be defined. Just as conclusions depend eventually on indemonstrable premises, so various terms are at last defined by means of indefinable concepts. The mind must grasp them intuitively from experience. That a piece of marble can become a statue and that an ignorant boy can become a learned man are matters of common experience. Again, a scholar asleep can wake up and start to study. An induction from such cases gives the concepts of potentiality and actuality. These are not to be defined, but are to be grasped by analogy. As he who can build is to him who is building, and as he who, though not blind, has his eyes shut is to him who sees, so potentiality is to actuality.
Aristotle advocates the idea that not all terms can be defined. The most basic of terms must appeal analogically to experience. Therefore, potentiality and actuality will not here be defined except with examples. Note that Clark is not giving his opinion yet. He is only expositing Aristotle.
With these indefinable concepts it is possible to define change or motion in general. The definition is: “the actualization of the potential as such is motion”; or, “the actuality of a potential being when it is actual and operative, not as itself, but as movable, is motion.”
Now that potentiality and actuality have been invoked, Aristotle defines motion as the actualization of a potential.
Aristotle elucidates with examples. When the buildable, in so far as it is buildable, is in actuality, the change called building is going on. Or, when we say that bronze is potentially a statue, it is not the actuality of bronze as bronze which is motion, but the actualization of “potentially statue,” the actualization of the bronze as changeable, which is motion.
Examples of what is and isn’t motion are provided. Now, Clark goes on to critique Aristotle.
Now, it may be quite true, as Aristotle goes on to argue, that all previous attempts to define motion were failures. This in itself, however, does not prove that Aristotle’s attempt was a success. On the surface it seems that his definition of motion uses the very concept being defined. Motion, he said, is the actualization of an object in so far as it is movable. But if the meaning of motion has not yet been determined, the phrase “as movable” adds no information. Next, the term actualization – unless we translate it actuality – apparently refers to some sort of process and hence presupposes a definition of change.
Clark argues that since the term actualization probably refers to a process, motion is presupposed in the definition of actualization. This would make Aristotle’s definition circular.
And, finally, not to press the problem of deriving the two terms by analogy, actuality and potentiality are hardly suitable for explanatory processes. No doubt bronze can be made into a statue – this is a matter of experience. But to explain why bronze can become a statue, the statement that bronze has such a potentiality does not increase our knowledge. To assert that a certain matter is potentially a certain form means only that similar matter in the past has become that form. This is a statement of fact; it is not an explanation of the fact.
First, I think it is important to call attention to Clark’s passing statement: “…not to press the problem of deriving the two terms by analogy…” Gordon Clark does not allow, here and in his other writings, that terms be allowed to be undefined. However, he does not want to refute that point here but rather show that the potentiality-actuality explanation still doesn’t explain motion, it just tells you that it happens. Clark concludes this section:
Perhaps Democritus was right, and there is no explanation. Motion is just an inexplicable factor of experience, and only particular motions can be defined or explained. Or, perhaps, the Eleatic arguments against motion were just so much conceptual jargon, and to refute them all that Aristotle needs is more conceptual jargon. In modern times, too, Bergson has complained that his immediate predecessors failed to explain motion.
Presumably, Clark is referring to the 19th-20th century French philosopher Henri Bergson. All this is quite interesting, and it underscores the importance of a continued re-examination of the basics of our thought. If motion is just a vague term describing who-knows-what, the world may perhaps be a bit different than we’ve been told it is.
Indeed, scientists have already rejected the Newtonian principles of motion. Perhaps it would be best for modern theologians to follow Gordon Clark’s example and construct and defend a system of theology that is not based on Aristotelian physics which has been mostly rejected by modern physicists. This is not to say that Quantum Mechanics or General Relativity are true either. There will probably be more successors. Rather, I think we need a foundation for the Christian faith that is stronger than Aquinas’ Cosmological Argument (which, if you read the Summa Theologica, you will see is heavily reliant on Aristotle’s physics, so the Classical Apologists should worry about these things). In fact, we ought to have a foundation for the Christian faith that can refute it.