Parmenides used the Principle of Sufficient Reason to argue that there was no such thing as change: If there was change, why did it happen when it happened rather than earlier or later? “Ex nihilo nihil fit”: nothing comes from nothing.
(Parmenides can be forgiven for not having known anything of quantum mechanics.)
The PSR is more famously associated with Gottfried Wilhelm Leibniz.
The argument runs that the principle of sufficient reason generates the truths of fact, which are contingent (M#36), and each of which states the connection between an existing individual substance and one of its infinitely many accidental features or relations.
For every entity X, if X exists, then there is a sufficient explanation why X exists*.
For every event E, if E occurs, then there is a sufficient explanation why E occurs.
For every proposition P, if P is true, then there is a sufficient explanation why P is true.
The reasoning runs that since the universe exists, there must be an explanation or cause for its existence. Since it is taken as incoherent to postulate self-causation (the cosmos' creating itself), it is assumed that the cause for the universe is necessarily something other than the universe itself. Considering plausible candidates for the cause of the universe, 'God' is proposed as being the best candidate since 'God' is defined as capable of creating a universe without being a part of the universe. Absent God, and the existence of the universe is taken to be inexplicable. (Which, of course, is the current state of astrophysical knowledge.)
The argument itself immediately raises the question of how 'God' came into existence in order to cause the universe. This obvious problem is conveniently ignored or dismissed-by-definition by theists. Even if we accept that the universe had a cause, and call this cause 'God', there is no further reason to assume that this 'God' is the God of the Bible.
A further problem is that it is by no means established that there need be a cause for the universe, even if it did come into existence at some finite time in the past (Big Bang). This is to say, there need not be a complex, intelligent cause, when the laws of physics then** in operation would suffice as an explanation.
Monadology #32. And that of sufficient reason, in virtue of which we hold that there can be no fact real or existing, no statement true, unless there be a sufficient reason, why it should be so and not otherwise, although these reasons usually cannot be known by us. (Theod. 44, 196.)
The PSR theme continued:
33. There are also two kinds of truths, those of reasoning and those of fact. Truths of reasoning are necessary and their opposite is impossible: truths of fact are contingent and their opposite is possible. When a truth is necessary, its reason can be found by analysis, resolving it into more simple ideas and truths, until we come to those which are primary. (Theod. 170, 174, 189, 280-282, 367. Abrege, Object. 3.)
36. But there must also be a sufficient reason for contingent truths or truths of fact, that is to say, for the sequence or connexion of the things which are dispersed throughout the universe of created beings, in which the analyzing into particular reasons might go on into endless detail, because of the immense variety of things in nature and the infinite division of bodies.
37. And as all this detail again involves other prior or more detailed contingent things, each of which still needs a similar analysis to yield its reason, we are no further forward: and the sufficient or final reason must be outside of the sequence or series of particular contingent things, however infinite this series may be.
38. Thus the final reason of things must be in a necessary substance, in which the variety of particular changes exists only eminently, as in its source; and this substance we call God. (Theod. 7.)
39. Now as this substance is a sufficient reason of all this variety of particulars, which are also connected together throughout; there is only one God, and this God is sufficient.
40. We may also hold that this supreme substance, which is unique, universal and necessary, nothing outside of it being independent of it,- this substance, which is a pure sequence of possible being, must be illimitable and must contain as much reality as is possible.
Refutations of the PSR include Hume’s imaginability argument and Peter van Inwagen’s argument that the PSR entails modal fatalism. William Rowe's criticism of the argument amounts to saying that we have no reason to believe PSR.
* Note that, if S is a sufficient cause of E, the presence of E does not necessarily indicate that E was caused by S. It is possible that E was caused by another agency or agencies.
** The laws of physics could have been different prior to the "Big Bang".
Blogs: Conceivability, Possibility, and the Ontological Argument for God's Existence : The Leibnizian Cosmological Argument : sufficient reason for conversation :
THE MONADOLOGY by Gottfried Wilhelm Leibniz translated by Robert Latta
Parmenides' Principle by Allan F. Randall.
Quantum Superposition, Necessity and the Identity of Indiscernibles by Allan F. Randall
Ex Nihilo Nihil Fit: Arguments New and Old for the Principle of Sufficient Reason by Alexander R. Pruss
Bobro, Marc, "Leibniz on Causation", The Stanford Encyclopedia of Philosophy (Summer 2007 Edition), Edward N. Zalta (ed.), url.
åå Apologetics Debunked åå
cosmological argument, Gottfried Wilhelm Leibniz, Monadology, Principle of Sufficient Reason ,