From Wikipedia, these four causes are listed at
- A thing's material cause is the material of which it consists. (For a table, that might be wood; for a statue, that might be bronze or marble.)
- A thing's formal cause is its form, i.e. the arrangement of that matter.
- A thing's efficient or moving cause is "the primary source of the change or rest." An efficient cause of x can be present even if x is never actually produced and so should not be confused with a sufficient cause. (Aristotle argues that, for a table, this would be the art of table-making, which is the principle guiding its creation.)
- A thing's final cause is its aim or purpose. That for the sake of which a thing is what it is. (For a seed, it might be an adult plant. For a sailboat, it might be sailing. For a ball at the top of a ramp, it might be coming to rest at the bottom.)
Edward Feser has recently been trying to revive the theory of all four causes, and has often claimed that the particular lack of final causes in modern physics is the source of many of its problems in understanding the nature of living organisms.
Feser says that he is encouraged in this respect by the renewed emphasis in the philosophy of physics on dispositions:
Recall first that for the Aristotelian-Thomistic (A-T) tradition, the fundamental sort of final causality that exists in nature is the “directedness” of an efficient cause toward the generation of its typical effect or range of effects. It is similar to what contemporary writers on dispositions and causal powers like C. B. Martin, John Heil, Brian Ellis, Nancy Cartwright, and George Molnar have in mind when they speak, for example, of the way dispositions are “directed toward” or “point to” their characteristic “manifestations,” or the way causal powers are “directed toward” their characteristic effects. Hence the directedness of brittle objects toward shattering, of soluble objects toward dissolving, of the phosphorus in a match head toward generating flame and heat, are instances of finality as that is understood in the A-T tradition. The A-T view is that unless we regard such “directedness” or “pointing” as immanent or inherent to the natural phenomena that exhibit such dispositions and causal powers, we have no way of making it intelligible why they have the manifestations and effects that they typically do. Causes and effects, dispositions and manifestations would become inherently “loose and separate,” so that any effect or none might follow upon any cause. Such Humean fantasies are for A-T an inevitable result of the abandonment of immanent final causes.I have also contributed to this study of dispositions, starting with my 1988 paper "Real Dispositions in the Physical World". This and related papers are available at the website www.generativescience.org. A recent book "Philosophy of Nature and Quantum Reality" studies them further, especially concerning quantum physics.
However, and this is my main point, the case for the four Aristotelean causes in modern physics is, in various respects, both weaker and stronger than Feser makes out, especially concerning his aim to base a new understanding of living creatures using 'form-matter dualism' (hylemorphic dualism).
The stronger case for the four Aristotelean causes comes from a closer examination of physics, and also on the recognition that there is something universal about the four causes. Boyle and later Laplace may have thought that they were getting rid of final causes, but in fact they had not. Even in the most simple corpuscular ontology -- according to which the world is made of particles like billiard balls that collide with each other -- there is still a need for final causes. That is because the corpuscles have to be 'perfectly elastic'. This 'elasticity' is exactly a disposition, of the kind that Feser was referring to in the paragraph I quoted. Elasticity is a final cause, strictly speaking. We might even say that the "corpuscles desire to maintain their original shape". Furthermore, the corpuscles have a form, namely that shape of the corpuscles. Admittedly, 'form' in Thomist philosophy has many more components than just that shape, but the shape is definitely one ingredient that explains the behavior of the bodies while interacting. I discuss the dispositions of classical physics in Chapter 3 of my book.
The weaker case of the the four Aristotelean causes is clear when we compare mechanistic and wholistic explanations of the behavior of living organisms. There are two main options:
- Maybe the final causes are those that depend on the final causes of the microscopic parts. This is the mechanistic or reductionist explanation.
- Or maybe the organism's final causes are more global or macroscopic aims, such as eating, growth, reproduction, or even mental desires for pleasure or satisfaction. These are the 'organismic' or 'wholistic' final causes.
In contrast to Feser's claim, we see that it is not the absence of final causes which leads to the reductionist account. Rather, it is the choice of specific final causes as the source of the observed behavior. Are the important final causes those related to the organism (and its desires) as a whole, or only those of its microscopic parts? The modern predilection is to choose the microscopic final causes. Hence the desire to read books about brain cells, neurons, and genes. It is the reason why the idea of a selfish gene has become popular.
This choice (between microscopic and macroscopic final causes) is the important choice to be made when trying to understand living creatures. We do not automatically understand them better by trying to postulate the existence of final causes, because (in fact) final causes never really went away.
The true issues are are clearly manifest, for example, in Syphax's post "Lingering questions about hylemorphic dualism". Here we see the tension between the causes arising from the microscopic parts of an organism, and the causes relevant to the whole organism. Are both kinds of causes present, or only the microscopic causes? And if more than microscopic final causes are effective, how to we understand (for example) the laws of conservation of energy and momentum? These are the interesting questions.