The argument for an uncausable First Cause sketched in earlier posts relies on a principle of Universal Causation. The principle of Universal Causation is a fundamental principle of reason. As such, its truth cannot be demonstrated from more fundamental principles. However, I can argue for the principle dialectically, pointing out the unacceptably high price of rejecting the principle.
Reason directs us to expect causes in the widest possible range of cases. My principle of Universal Causation makes only one exception: that of strictly uncausable things. But this exception is not really an exception at all, since, if there are any strictly uncausable things it is, by definition, inconceivable that they should be caused.
One might object that a principle of universal causation ought to be a metaphysical principle (a principle about things in the world) and not an epistemological principle (a principle about what we can know). But I have defined broadly causable in terms of what can be known a priori.
I would respond that this epistemological principle is adjacent to an equivalent principle that is purely metaphysical. The reason for this equivalence is that I have used secondary conceivability: conceivability given the real essence of a thing. Consequently, broadly causable as I have defined it is equivalent to a purely metaphysical notion: metaphysically broadly causable.
Metaphysically broadly causable. A thing is metaphysically broadly causable if and only if the infima species to which it belongs has a kind-essence that does not entail that nothing of that kind has a cause.
If an essence entails that things of a certain cannot have a cause, then we could know that those things cannot have a cause, if we knew that essence. And vice versa. So, my original notion of broadly causable and this new notion of metaphysically broadly causable are equivalent. For the same reason, strictly uncausable and metaphysically strictly uncausable are equivalent.[1]
The principle of Universal Causation excludes the strictly uncausable. Should we exclude anything else from the scope of the principle? There are several reasons for saying, No.
Let’s say that a thing whose existence is broadly causable but uncaused a brute existent. A plurality of things whose joint existence is broadly causable but uncaused would be a brute plurality. Methodologically, we should reduce the number of brute existents and brute pluralities to the smallest set possible. That would be the empty set, since there is no compelling reason to posit any brute existents or brute pluralities at all. In fact, we should treat brute existents and brute pluralities as inconceivable.
If brute existents and brute pluralities are conceivable, is there any limiting principle? Is there a type of thing F of such a kind that can we say that brute pluralities of type F are conceivable, but not brute pluralities that do not belong to F?
It’s hard to see what that limiting principle would be. It makes sense to ask, what kinds of thing can be caused by things of type A? For example, what sorts of things can human being cause to exist? What sorts of things can waterfalls or meteor showers cause to exist? And so on. But it doesn’t make sense to ask: what sort of causable things can exist without being caused by anything? It seems that if any causable thing could exist without being caused, then every causable thing could exist without being caused. There doesn’t seem to be any limiting principle. If we said that things of some specific type of causable thing could not exist without being caused, what would be the explanation for this impossibility? In the absence of a principle of universal causation, what could prevent any causable thing from existing brutely?
If brute pluralities are conceivable, so are brute existents. There’s no reason why it would be easier for a numerous collection of entities to exist uncaused than for an individual to do so. So, if we rule out brute existents, we should rule out brute pluralities as well. So, the Pluralized version of the principle of Universal Causation is just as reasonable as the Simple version.
If brute existents are conceivable, then it is impossible to say that brute existents are unlikely or exotic (i.e., distant from the actual world or from any actual situation). What is likely or unlikely (with a certain probability) is the production or non-production of a certain kind of event by a certain kind of mechanism. There is nothing that could explain why an uncaused event should have one probability rather than another. Hence, we cannot conceive of a situation in which it is unlikely that an uncaused event should occur.
For similar reasons, if brute existents are conceivable, it would make no sense to suppose that certain kind of brute existents are possible in certain kinds of situations, while other kinds of brute existents are impossible. What is uncaused is unregulated and uncontrolled. If anything can exist uncaused, then anything could begin to exist without cause in any possible situation.
Consequently, anyone who believes in brute existents can have no explanation for why we don’t see uncaused entities of a wide variety of sorts appearing uncaused all the time. The absence of clear counterexamples to the principle is strong empirical evidence for it.[2]
Could a law of nature (like a law of conservation of mass or mass-energy) rule out certain kinds of brute entities’ appearing in certain circumstances without ruling out all brute entities? This proposal faces a dilemma: either the law is merely descriptive or it is prescriptive. If descriptive, it merely describes the fact that there have been no brute existents, at least none since the Big Bang. It doesn’t offer any explanation of this fact or provide any grounds for supposing such brute existents to be impossible. If prescriptive, the law of conservation must presuppose the principle of Universal Causation. Without the principle of Universal Causation, the conservation law could tell us that existing things lack the power to produce a set of things with a net increase or decrease of energy, but it could not rule out the uncaused appearance or disappearance of energy from the world. In the absence of the principle of Universal Causation, there would be no explanation for the impossibility of such violations of the conservation of energy. If brute existents were possible, there is no possible mechanism by which their existence or non-existence could be prevented or, indeed, controlled or regulated in any way.
Finally, I will point out that denying the principle of Universal Causation undermines various categories of knowledge, leading to various forms of radical skepticism (Pruss and Koons 2021). First, if the principle of Universal Causation were false, we would be unable to have any knowledge of the future, since any current factors on which we might rely to forecast the future could at any time be overwhelmed by unpredictable and uncaused brute existents. Similarly, any statistical knowledge about the propensities of things would be impossible, since any experiments that we have run in the past could have been distorted by uncaused factors (Pruss 2017).
In fact, I would argue that, in the absence of the principle of Universal Causation, we would have no empirical knowledge at all. My current sense data and memory impressions ground my knowledge of the world only on the assumption that they have been caused in the right way by entities of the appropriate kind. If my current sense data and memory impressions were instead brute existents, then I would have absolutely no empirical knowledge. I would be in a condition every bit as bad as the scenario that Descartes imagined in his First Meditation, where he supposes that his mind and all its contents were caused by a deceiving demon (Descartes 2008).
In fact, the threat from the possibility of brute existents is much worse than was the threat of Descartes’ imagined demon. We can plausibly suppose that Descartes’ demon, even if possible, is extremely improbable, and an extremely extravagant, recherche hypothesis. But, as I have argued, if the principle of Universal Causation were false, there would be nothing improbable or extravagant about the hypothesis that all the current contents of my mind are brute existents.
If the principle of Universal Causation were false, there would be no reliable processes of any kind, and so no empirical knowledge, since empirical knowledge must be the result of a reliably truth-tracking process.
These reflections support the conclusion that, not only can the truth of the principle be known, the principle can and must be known a priori. If we have to take the brute-existent hypothesis seriously, then all my empirical knowledge would be undermined. The only way to exclude that possibility without vicious circularity is to do be able to appeal on a priori grounds to the principle of Universal Causation. If I do not know a priori that Universal Causation is true, I cannot exclude the brute-existent hypothesis from serious consideration. And, so, I could not know that I have any empirical knowledge.
In addition, if I don’t know that I have any empirical knowledge at all, I don’t have any empirical knowledge in fact. The live (empirically accessible) possibility that I lack all empirical knowledge would serve as a defeater of all my empirical knowledge. There are some central or paradigmatic cases of knowledge (like my knowing my own name, or my knowing that I have a hand) which are such that, if I have any empirical knowledge at all, these would be clear and obvious of knowledge. If there are clear and obvious cases of my having empirical knowledge, then I can know that I have some empirical knowledge. So, if I cannot know that I have any empirical knowledge, it follows that I cannot have any empirical knowledge in fact.
Here is the argument:
- If I cannot know the principle of Universal Causation a priori, then the skeptical brute-existent hypothesis (the hypothesis that all the current contents of my mind, including all sense data and memory impressions, are uncaused) is for me a live possibility (a conceivable situation that is neither unlikely nor known by me to be possibly remote from the actual world, given the current contents of my mind).
- I can know a priori that if the skeptical brute-existent hypothesis were true, I would not have any empirical knowledge.
- Therefore, if I cannot know the principle of Universal Causation a priori, then my lacking all empirical knowledge is for me a live possibility. (From 1, 2)
- If the falsity of a proposition is for me a live possibility, then I cannot know that proposition.
- Therefore, if I cannot know the principle of Universal Causation a priori, I cannot know that I have any empirical knowledge. (From 3, 4)
- If I have any empirical knowledge, then I know that I have at least some empirical knowledge.
- I do have some empirical knowledge.
Therefore, I can know the principle of Universal Causation a priori. (From 5, 6, and 7)
[1] It is important to distinguish metaphysically broadly causable from a different notion: that of its being metaphysically possible for a particular thing to be caused. Even if it is metaphysically impossible for a particular thing to be caused to exist (perhaps because its individual identity it necessarily tied to its being uncaused), the thing could still be metaphysically broadly causable, so long as it belongs to a specific kind of thing whose essence is compatible with being caused. Both notions are metaphysical in nature, but the category of metaphysically broadly causable is broader in scope.
[2] Some suppose that the indeterminism of many interpretations of quantum mechanics counts as a counter-example to the principle. However, this confused indeterminism with the absence of a cause. Quantum events are not determined by their predecessors, but they are caused by them. See Anscombe’s inaugural Cambridge lecture on this crucial distinction (Anscombe 1993). Similarly, the virtual particles that appear spontaneously in the vacuum (according to quantum field theory) are not uncaused: they are caused by the quantum field that fills the “vacuum,” a field with the causal power to generate pairs of virtual particles.
The Analytic Thomist 