One should assume that with his four causes Aristotle wants to give us some very general starting points for an investigation of reality. Yet, at first sight his four causes (maybe except the efficient cause) seem only applicable for the physical objects of our day-to-day experience.

  • The material cause: “that out of which”, e.g., the bronze of a statue.
  • The formal cause: “the form”, “the account of what-it-is-to-be”, e.g., the shape of a statue.
  • The efficient cause: “the primary source of the change or rest”, e.g., the artisan, the art of bronze-casting the statue, the man who gives advice, the father of the child.
  • The final cause: “the end, that for the sake of which a thing is done”, e.g., health is the end of walking, losing weight, purging, drugs, and surgical tools.

(Stanford Encyclopedia of Philosophy, "Aristotle on Causality")

Ok, let's take a light ray as an example:

  • material cause: umh... 'light stuff'? Pure energy? Electromagnetic radiation? Photons? All that doesn't seem very material...

  • formal cause: I have no idea... the wavelength of the light, maybe?

  • efficient cause: ok, that's comparatively easy. If the light came from the sun, the efficient cause would be the sun. On the other hand, let's say the light ray hits a mirror... what now? After hitting the mirror, does the light ray get destroyed and a new light ray comes into existence with the efficient cause 'mirror'? Or is it the same light ray which just got reflected?

  • final cause: I have no idea.

And now try this for electron or black hole.

Obviously, a metaphysics that only works in middle world is useless. But maybe that's not the case and we just have to understand Aristotle differently. How would one defend him?


2 Answers 2


1) Aristotle develops his classification from the study of mesocosmic (= middle world) objects only. Further stimulation came from the discussion of Plato's theory of forms. E.g. causa formalis resembles the Platonic concept of form.

Aristotle did no know about microcosmos. Concerning macrocosmos he had only a theoretical - and wrong - conception.

Aristotle gives in Metaphysics a history of philosophy. He emphasizes that his forerunners detected only fractions of the different types of cause (aition). Hence he considers his doctrine of 4 causes a progress in philosophy.

2) I agree with you that causa finalis does not apply to physical objects. But to a certain degree it applies to animals and plants when considering the role of genes. Of course, the genotype defines only the domain of possibilities. Not every possibility will be realized. Most of all causa finalis describes the way that humans make their decisions.

3) Concerning your interesting example to explain light rays - microphysics - by the means of Aristotle's doctrine, my proposal is:

  • causa materialis: Photon E = h*ny, m = E/c**2.
  • causa formalis: Any model from a theory of light from physics: Optics, Maxwell's electrodynamics, quantum electrodynamics. But we operate only by using models, any essence remains unknown. It is even dubious whether essence is a meaningful notion in this context.
  • causa efficiens: Emission of light in atoms, pair annihilation.
  • causa finalis: not applicable.

I think one can make a similar list for electron and black hole.


At least in his Physics, Aristotles classification of causes apply to change; he offers examples which aren't drawn from the physical world: a doctor who cures a patient.

He notes, that in many cases his classification collapses - the formal and efficient, for example are often identical; and perhaps going by this we may find in a particular change a cause might not apply: the final purpose of doctoring a patient is to bring him to health, the efficient cause being the doctoring; but there does not appear, at first glance an obvious material cause.

In the example you provide, light, there is no change - so in a sense nothing to explain; but if say it was an electron absorbing a photon and this jumping into a higher orbit - one could, perhaps classify the causes - if one had a mind or a need to; but there, is there an actual pressing need?

Light is understood in many ways: when I switch on a table-lamp to read a book, both efficient and final cause are easy enough to discern - but the material and formal cause, less so - perhaps they are not there.

Again, when one looks through a history book, that explanations are given in terms of actors that act towards some purpose - so again, both efficient and final cause is there.

These examples suggest that when voluntaristic will is identifiable both efficient and final causes are easy to find - and when not, not.

  • His causes apply only to change?? How could the material cause ever explain change?
    – R. Neville
    Dec 11, 2015 at 9:08
  • When there is no change in a world; what is there in that world to explain? His idea of what constitutes change and cause is different from our standard conceptions ie coming-to-be is a change, which might be called emergentism now. Dec 11, 2015 at 9:17
  • Material cause certainly doesn't sound like a cause in today's language; but Aristotle was working with a different semantic range: when I think of cause, I think of cause and effect - and this generally will be efficient cause: so it's not surprising that material cause sounds surprising; but Aristotle is also working with a notion of change that relies on opposites - and the opposite of a change, in the change itself, is what is preserved through its change - ie it's matter; what he's doing by naming it as material cause is to identify it as an important component of change. Dec 11, 2015 at 9:30
  • When I translate a poem from one language to another - a change of a kind; the matter that is preserved is its sense - or ought to be; there, one might ask has its sense been preserved. Dec 11, 2015 at 9:33
  • Actually, it's interesting to note, that there material cause can be identified with final cause; after the final purpose of a translator is obtain a translation that preserves sense. Dec 11, 2015 at 10:07

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