The need for something to exist presupposes the existence of God
This argument is used in the debate Does God exist?.
This argument is an objection to The universe is contingent.
Summary
Quotes
“The position Meillassoux imagines, namely that something necessarily exists and that the universe is radically contingent, is possible [...] but on one strict condition: that there is also a necessary being! But to claim that nothingness is impossible without positing a necessary being seems absurd to us. The only source of necessity in Meillassoux's reasoning is a pure logical epiphenomenon. It is a verbal necessity, not rooted in any real necessity. Let's go back to his theorem [...] In plain English: [For any x and any y, it is necessary that if x exists instead of y, it should be contingent] implies [there is necessarily a contingent x or y]. This reasoning is invalid. The necessity he is dealing with in the first proposition is a purely conditional necessity, it does not concern the existence of anything, but only the sequence that links (according to his thesis) the fact of existing to that of being contingent ("if x exists, then necessarily x is contingent", not "it is necessary that an x exists, which is contingent"). In reality, the first proposition is a tautology, which states that when one is part of the set of contingent beings, it is necessary that one be a contingent being. Which is true, but not very informative. Meillassoux's argument is not a proof, but the simple assertion of a definition: "By definition all x is contingent, therefore all x is contingent." In short, "from the implication that if something exists, it must be contingent, it is impossible to draw the conclusion that something necessarily exists. To generate a situation of necessity without a necessary being in the picture is simply impossible". We are sometimes tempted to do this by imagining reciprocal conditioning relationships between contingent terms, like Smith and Smith who think they can protect themselves from a fall by clinging to each other, but the maneuver is illusory.”
