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WillowOne's Positions

Argument from the Principle of Sufficient Reason

Form

Leibniz's version (On the Ultimate Origination of Things, 1697; Monadology, 1714, §§31–39):

  1. The Principle of Sufficient Reason (PSR): for every fact, there is a sufficient reason why it is so and not otherwise.
  2. The totality of contingent facts (the universe, however far back it goes) is itself a fact.
  3. Its sufficient reason cannot lie inside it, since nothing contingent can be the reason for the totality that includes it.
  4. Therefore the sufficient reason for the universe lies outside it, in something that exists necessarily and explains itself.
  5. That necessary, self-explaining being is God.

The argument differs from the Kalam Cosmological Argument in needing no beginning, and from the Argument from Contingency in resting all its weight on the PSR as a universal law rather than on the contingency of particular things. The modern defence is Alexander Pruss's.

My Positions

  1. The PSR is a working habit, not a law. "Look for a reason" is the right rule for enquiry, because reasons usually turn up. It does not follow that every fact has one. Nothing demonstrates the principle, and it cannot be demonstrated without using itself (Münchhausen trilemma). Some facts may simply be brute, and the honest response to a brute fact is to say so, not to name it.
  2. The strong PSR destroys the contingency it needs. If every fact has a sufficient reason, so does the conjunction of all contingent facts. That reason must be a necessary truth, or it would be part of the conjunction. But whatever follows sufficiently from a necessary truth is itself necessary. So nothing is contingent, and premise 2 has no subject. This is Peter van Inwagen's objection, and the standard reply, that God's choice is free and so explains the world without necessitating it, makes God's choice a fact without a sufficient reason, which the PSR forbids. The argument ends by exempting the very thing it was built to exclude (Special Pleading).
  3. "Outside the totality" is empty. Once the totality of contingent facts is explained by a necessary being, the fact that this necessary being produced this world rather than another is a further contingent fact, and it is inside the totality. The explanation never escapes the circle it drew.
  4. Physics gives counter-examples to the strong principle. Why did this particular nucleus decay now and not a moment later? On every standard interpretation of quantum mechanics there is no sufficient reason, only a probability. The theist can insist there is a hidden reason, but then the PSR is being used to generate the facts it was meant to explain.
  5. The weak principle does not reach the conclusion. Pruss and Richard Gale retreat to "every fact could have an explanation", which is harder to deny, but their derivation of God from it goes through a modal step of the same kind that sinks the Ontological Argument: from "possibly explained" to "actually explained by a necessary being" is a long way, and the distance is bridged by the same assumption about possibility and necessity.
  6. A self-explaining being is a stopping point with a name. Every chain of explanation ends in a brute fact, a circle, or a regress. "God exists necessarily" is the first of these said in a reverent voice. If something can be its own sufficient reason, the universe is as good a candidate and a cheaper one (Occam's Razor - Principle of Parsimony).
  7. I do not know why there is something rather than nothing. I see no reason to think the question has an answer of the kind the argument wants, and I decline to let my incomprehension be used as evidence (Owens Tryptic of Ignorance, Appeal to Ignorance).

Notes

David Hume made the essential point in 1779 (Dialogues, Part IX): if each member of a collection is explained, it is a further demand, and an unwarranted one, to ask for an explanation of the collection as a whole (Composition Fallacy). Leibniz's own answer to his own question, in the end, was that God chose the best of all possible worlds, which gave Voltaire Candide and the rest of us the Problem of evil.

Sources

  • Leibniz, G. W., On the Ultimate Origination of Things (1697); Monadology (1714), §§31–39
  • Pruss, A., The Principle of Sufficient Reason: A Reassessment (2006)
  • van Inwagen, P., An Essay on Free Will (1983), pp. 202–204, on the PSR entailing necessitarianism
  • Gale, R. and Pruss, A., "A New Cosmological Argument", Religious Studies 35 (1999)
  • Hume, D., Dialogues Concerning Natural Religion (1779), Part IX

Also see