Why is there anything at all?
Does existence itself have an explanation, or is it simply there?
I
A necessary being
There is something because something exists necessarily, something that could not have failed to exist and so needs no further explanation.
- Best argument
- Contingent things, which could have failed to exist, need explanations beyond themselves. The whole collection of contingent things is itself contingent. So the ultimate explanation must lie in a being whose existence is necessary. Ibn Sina (Avicenna) developed a version of this argument from the 'necessary existent', and Gottfried Wilhelm Leibniz and Thomas Aquinas gave others. Many identify this being with God.
- Strongest objection
- David Hume and Immanuel Kant questioned whether 'necessary existence' makes sense: anything we can conceive existing, we can conceive not existing. And even granting a necessary being, it is a further step to show it has the attributes of a personal God.
- The reply
- Defenders reply that necessity need not be conceptual; it could be metaphysical, like the necessity of mathematical truths, which also exist in every possible world.
- Defended by
- Gottfried Wilhelm Leibniz, Ibn Sina (Avicenna), Thomas Aquinas
II
A brute fact
There is no reason. The existence of the universe is simply a fact, and the demand for an explanation of everything is misplaced.
- Best argument
- Explanation must stop somewhere, and the principle of sufficient reason may simply be false. Bertrand Russell, debating Frederick Copleston on the radio in 1948, replied, in effect, that the universe is simply there, and that is all that can be said. Every chain of explanation ends in something unexplained; the universe is a natural place for it to end.
- Strongest objection
- Accepting a brute fact at the foundation of everything seems to give up on understanding just where it matters most. And if things can exist for no reason, why not expect bizarre unexplained events all the time?
- The reply
- Brute-fact theorists answer that the regularity of the world can itself be part of the brute fact; accepting one unexplained starting point does not license expecting chaos.
- Defended by
- Bertrand Russell, David Hume
III
Nothing is unstable, or impossible
Nothing is not a real option. Either 'nothing' is incoherent, or the laws of physics make a universe inevitable.
- Best argument
- Some physicists argue that the quantum vacuum is unstable and naturally produces universes. Some philosophers argue that a state of absolute nothingness is impossible because, for example, it would still be true in that state that there is nothing, and truths are something. Others note that of all the ways things could be, only one is 'nothing', so something is overwhelmingly likely.
- Strongest objection
- A quantum vacuum governed by laws is not nothing; it is a very particular something. Physical explanations of the universe's origin move the question back to why those laws exist. As for probability, it is unclear that 'ways things could be' can be counted at all.
- Defended by
- Lawrence Krauss, Peter van Inwagen
IV
The question is meaningless
The question looks deep but misuses words. 'Why' asks for causes within the world, and cannot be applied to the world as a whole.
- Best argument
- Ludwig Wittgenstein wrote that 'not how the world is, is the mystical, but that it is'. Logical positivists went further and called the question meaningless, since no possible observation could answer it. Asking for the cause of everything is like asking what is north of the North Pole.
- Strongest objection
- That a question cannot be settled by observation does not make it meaningless; the verification principle that says so cannot itself be verified by observation. Many people find the question perfectly clear, if unanswerable.
- Defended by
- Ludwig Wittgenstein, Rudolf Carnap
For the full background, variations and open questions, read the entry: Why is there something rather than nothing?.