Philosophy of Nature: III. The Four Causes
D: Final Cause
In addition to the formal, material, and efficient causes we have considered so far, Aristotle discovered that no explanation is complete unless one includes another, last cause (pun intended). The final cause, according to Aristotle and Aquinas, is that for the sake of which motion happens. It is the end, goal, or purpose for which any activity or motion takes place.
The study of the final cause is called “teleology” from the Greek word telos, meaning “end”. The final cause provides the ultimate explanation of motion since each thing moves to achieve some end (whether it’s the early bird trying to catch the worm or the electron moving to a different energy state). Motion presupposes incomplete beings which act to attain some goal. The pursuit of the goal (final cause) is what puts the world in motion.[1]
One can most easily understand this notion of final cause by considering motions which humans initiate. A sculptor sculpts in order to produce a statue, which he might do in order to make money, express himself, or make the world more beautiful (among innumerable other reasons).
Also, because, as Aristotle says in the second book of the Metaphysics, everything which acts, only acts by tending toward something, there must be some fourth [cause]: namely, that which is intended by the agent; and this is called the end.[2]
Aristotle and Aquinas understood that final causes or goals are at work everywhere in nature, in every motion and activity, even for inanimate substances and insensate living things (plants) as well as animals and human beings. Every natural motion, of both animate and inanimate substances, is an incomplete act that tends toward its completion. The completion of the goal of every motion is the final cause or end for which the agent acts. The final cause is the purpose for which a voluntary agent (animal or human) acts, and even non-voluntary agents pursue goals or ends in their agency.
It should be understood that, while every agent, whether natural or voluntary, intends an end, nevertheless it does not follow that every agent knows the end or deliberates about the end. For, to know the end is necessary in those things whose actions are not determined, but which may act for opposed ends, as, for example, voluntary agents do. And so, it is necessary that they know the end by which they determine their actions. But in natural agents the actions are determined; hence, it is not necessary to choose those things which are for the end.[3]
Thus, natural substances, in acting in the manner that their intrinsic powers and proper activities require, naturally tend toward the goal of such activity.
For the Aristotelian, final causality or teleology (to use a more modern expression) is evident wherever some natural object or process has a tendency to produce some particular effect or range of effects. A match, for example, reliably generates flame and heat when struck, and never (say) frost and cold, or the smell of lilacs, or thunder. It inherently “points to” or is “directed towards” this range of effects specifically, and in that way manifests just the sort of end- or goal-directedness characteristic of final causality, even though the match does not (unlike a heart or a carburetor) function as an organic part of a larger system. The same directedness towards a certain specific effect or range of effects is evident in all causes operative in the natural world. When Aristotelians say that final causality pervades the natural order, then, they are not making the implausible claim that everything has a function of the sort biological organs have, including piles of dirt, iron filings, and balls of lint. Rather, they are saying that goal-directedness exists wherever regular cause and effect patterns do.[4]
In animate nature, the final cause is not some goal beyond the thing that acts, but the term of its own acting, a goal that is for the sake of the substance acting. Fruit does not grow to be food for humans and animals, but for the sake of generating another tree. Thus, typically, in generation, the final cause is the full actualization of the form, i.e. the mature adult of whatever species is generated.
Some accuse the Aristotelian understanding of final causes as being anthropomorphic. However, Aquinas makes clear that the fact that nature works “always or for the most part” to produce the same result is evidence that there is a genuine goal or end, a final cause at work.
Therefore, it is possible for the natural agent to tend toward an end without deliberation; and to intend this is nothing other than to have a natural inclination to something. [5]
Final causes, indeed, provide the ultimate explanation of the action and motion of material things, not only for why a given substance acts as it does, but also for the other causes being causes.
Therefore, the end is the cause of the causality of the efficient cause, because it makes the efficient cause to be effecting [facit efficiens esse efficiens]. Similarly, [the end] makes the matter to be the matter and the form to be the form, since matter does not receive the form except for the sake of the end and the form does not perfect the matter except for the sake of the end. Therefore, the end is called the cause of causes, because it is the cause of the causality in all causes.[6]
Final causes are at work throughout all of nature, in every motion and change, substantial and accidental, and together with the material, formal, and efficient causes, complete our understanding for the coming to be, activity and operation, and continuation in being of every natural, material thing. The understanding of final causes is a crucial and essential component of coming to know the truth of things, and their elimination from a scientific account renders it inadequate.
The final cause makes the process of motion intelligible. Without final causality, the operation of nature would be meaningless. It would achieve nothing. It seems, however, that something is achieved by motion. Motion seems to happen for the sake of obtaining something which we may describe as the fulfillment or perfection of the mobile being and in which we find the very reason for its motion. The final cause, as a good to be attained, is what moves the agent to act. As such, it is the first cause — the foundation of all causal activity.[7]
As Aquinas uses the notion of efficient causality in the first three of his Five Ways of proving the existence of God which (we noted above), so the notion of final causality serves as the basis for another of these five proofs, i.e. the Fifth Way.[8] Since material things act for an end unknowingly and involuntarily, there must be an intelligent First Ordering Cause which directs them to their proper, natural ends (which Cause Aquinas identifies as God). It should be noted, however, that the proof does not argue that there is one final cause or purpose to the whole universe, nor that this ultimate final cause is God (even though Aquinas does believe this). The proof merely asserts that something or other acts for an end which it does not know and does not choose, and that this fact shows that there must be a cause of those things which directs them to their final causes. The notion of final cause is also the basis of Thomistic Natural Law in which Aquinas argues that humans’ natural inclinations and purposes, their natural final causes, entail that persons have natural rights and obligations which no human law can abrogate or contradict, the right and duty to protect life, liberty, education, truth, virtue, and justice.
[1] Dodds, The Philosophy of Nature, p. 79.
[2] On the Principles of Nature, c. 3.2.
[3] Ibid., c. 3.2.
[4] Feser, Aquinas: A Beginner’s Guide, pp. 29-30.
[5] On the Principles of Nature, c. 3.3.
[6] Ibid, c. 4.4.
[7] Dodds, Philosophy of Nature, p. 79-80.
[8] ST Ia, q, 2, a. 3; again, see The Five Ways.
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