I'm reading Edward Feser's book Five Proofs of the Existence of God. On pages 32-33 he introduces the principle of proportionate causality (PPC). I'm having trouble understanding what precisely virtual and eminent causes (of a form) are. He gives an example, but from the example I'm still not clear what the precise definition is supposed to be, or even what the difference between eminent and virtual causes are supposed to be.

Here's what he writes:

Let’s now say a little more about cause and effect. We’ve noted that when something is either changed or caused to exist, a potential is actualized, and that something already actual must be what actualizes it. This is sometimes called the principle of causality. A further point to make about cause and effect is that whatever is in some effect must in some way or other be in the cause, even if not always in the same way. For a cause cannot give what it does not have to give. This is sometimes called the principle of proportionate causality.

Suppose, for example, that I give you $20. The effect in this case is your having the $20, and I am the cause of this effect. But the only way I can cause that effect is if I have the $20 to give you in the first place. Now there are several ways in which I might have it. I might have a $20 bill in my wallet, or two $10 bills, or four $5 bills. Or I may have no money in my wallet, but do have $20 in my bank account and write you a check. Or I may not have even that, but I am able to borrow the $20 from someone else, or work for it, so that I can go on to give it to you. Or perhaps I have a friend who has a key to the U.S. Treasury printing press and I get him to run off an official $20 bill for me to give to you. Or to take an even more farfetched scenario, suppose that in order to guarantee that you get that $20 I somehow convince Congress to pass a law which permits me personally to manufacture my own $20 bills. These are all various ways in which I might in theory give you $20. But if none of these ways are available to me, then I can’t do it.

Again, these are different ways in which the cause may have what is in the effect. When I myself have a $20 bill ready to hand and I cause you to have it, what is in the effect was in the cause formally, to use some traditional jargon. That is to say, I myself was an instance of the form or pattern of having a $20 bill, and I caused you to become another instance of that form or pattern. When I don’t have the $20 bill ready to hand but I do have at least $20 credit in my bank account, you might say that what was in the effect was in that case in the cause virtually. For though I didn’t actually have the $20 on hand, I did have the power to get hold of it. And when I get Congress to grant me the power to manufacture $20 bills, you might say (once again to use some traditional jargon) that I had the $20 eminently. Because in that case, I not only have the power to acquire already-existing $20 bills, but the more “eminent” power of causing them to exist in the first place. When it is said, then, that what is in an effect must in some way be in its cause, what is meant is that it must be in the cause at least “virtually” or “eminently” even if not “formally”.

Obviously virtual and eminent causes are there to make sure that "the obvious objection" to the PPC doesn't work. The obvious objection when hearing that "whatever is in some effect must in some way or other be in the cause" is to say stuff like things that are not hot can cause something to be hot, things which are not green can cause something green (mixing of blue and yellow paint for example), one does not need to have an injury to cause an injury, etc., etc. The defender of PPC would saying the forms of hot, green, or injury exist virtually or eminently in the cause(s)... I get that they want to say that the form exists "potentially" in its cause, but how is this to be understood precisely (i.e. not just by examples and analogies), and why is there both virtual and eminent causation?

[I'm tagging this with the "Aristotle" and "Aquinas" tags, since Feser himself is an Aristotelian-Thomist and big on scholastic metaphysics. Perhaps this principle is best understood in those metaphysical frameworks, and is discussed elsewhere in their works?]

  • 1
    Polivka in The Principle of Proportionate Causality does only slightly better:"It is called virtual if the perfection may be produced by a thing: an explosive charge “imparts velocity to a projectile” but it does not contain velocity as such... The term eminent is always used paired with virtual or formal (where virtual or formal become adverbs). It means that the perfection possessed by the cause is of a greater magnitude than the substance which is receiving the perfection".
    – Conifold
    Apr 16, 2019 at 20:05

1 Answer 1


Adam. I'll do what I can to answer your somewhat ambiguous questions. If I understand you correctly, you are asking how, precisely, eminent and virtual causality are understood and why they are classified differently. I can only make sense of that if I add an unstated observation that you consider eminent and virtual causality to be identical; hence, the question: Why the different classification? But pursuant to the examples Feser supplies, they are not the same. So, I guess we'll have to take it further and try to explain how they relate to God's causal efficacy.

Pursuant to our observation of change, every contingent being is composed of two principles: act and potency. Since no composed being can cause itself, and since every composed being must be caused, the only logical stopping point is a being of Pure Act. Feser defends these assertions in detail in his books Aquinas, The Last Superstition, and Scholastic Metaphysics.

Since it is metaphysically impossible for there to be more than one Pure Act, and since Pure Act is the cause of all contingent being, said cause can neither be formal nor virtual. For if it were, creation would be like-for-like. Pure Act cannot be created for that would be an instance of joining an essence with existence which is impossible for Pure Act. A virtual representation is also impossible for similar reasons. Creating Pure Act virtually is a contradiction in terms. All contingent being has its existence through something other than what it is. Only Pure Act is Being Itself, so even a "virtual" being would be radically different from Pure Act. Consequently, the only option is that all perfections held by contingent (necessarily finite and imperfect) being exist perfectly, infinitely and eminently in God and thus finite being exists by the eminent creation of God.

  • Hi Bill, welcome, and thanks for the answer. I am aware of the act-potency distinction which you mention, but I'm still not really following. The first time you mention virtual causation in your answer (after the introductory paragraph) is in the sentence "Since it is metaphysically impossible for there to be more than one Pure Act, and since Pure Act is the cause of all contingent being, said cause can neither be formal nor virtual." Here and in the following sentences you use the notions of virtual and eminent causes, with defining them. But this is exactly my question; how are they defined? Jun 12, 2019 at 19:54
  • After coming back to this question with fresh eyes, near as I can tell Feser's examples try to show something like this: X formally causes property P in being Y, when X has the property of P already and so "passes it on" to Y; X virtually causes property P in being Y, when X can "redirect" already existing instances of P, that are present in some other beings, from these other beings into Y; and X eminently causes property P in being Y otherwise; that is X can directly, by way of its own nature, bring new instances of P into existence. Is this correct? If not, maybe you can help clarify? Jun 12, 2019 at 19:56
  • As far as I can tell, I think my above reading of the PPC is consistent with your example of God creating too. God doesn't create formally, because otherwise the being that is created would be pure act too, contradicting the fact that it was created (and so had the potential to not exist). And God doesn't create something virtually either, because there are no other instances of the form to draw from. So God must have created in some other direct way, by causing new forms to exist where there are none. (I am rephrasing your answer to check my understanding.) Jun 12, 2019 at 20:13
  • Hello again, Adam. I was not aware that you were looking for a formal definition. For eminent causality, I would say that X can cause what is analogous to X (aX) in being Y because X, by virtue of its nature, can bring new instances of aX into existence. On Thomism, God does not "have" properties. We separate and categorize them in God due to our finite perspective, but as Pure Act, they are all one in God.
    – David
    Jun 13, 2019 at 4:10
  • By way of illustration, say you're a king who does not use currency (money is only used by your subjects). As the sovereign of your kingdom, you can order your treasury department to print, say a $50 bill for one of your subjects. The person holding that bill has a "power" analogous to yours in a very different and limited way. You do not need currency because your power is absolute, so whatever currency is owned is an extremely imperfect likeness of your wealth. That's how eminent causality works.
    – David
    Jun 13, 2019 at 4:18

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