It is not conceivable that successions of causes and effects leading to now should have sprung from nowhere. Sclauzero of Toronto

These words can inspire ‘nondemonstrative’ arguments for the existence of God that would proceed from very general facts about the world. Never mind, they say, details and ways in which the world is special. It and that is enough. For causes and reasons are required for that, causes and reasons need causes and reasons, and, eventually, if these systems are to be grounded and not to have sprung from nowhere, they must relate all to first and ultimate causes and reasons. Two such arguments – two rather different ‘takes’ on Sclauzero's words – will be examined. The argument of the next chapter, for an ultimate reason for The World, can be seen as a response to problems of the other, the argument of the present chapter, which is for a first cause for things.

PART 1, QUESTION 2, OF SUMMA THEOLOGICA – “THE EXISTENCE OF GOD”

The question of the existence of God is resolved by St. Thomas Aquinas into three questions.

Article 1: “Whether the Existence of God Is Self-evident?” He says, Yes, but not to us. (ST I q2,a1 pp. 18–19.) That God exists is self-evident in itself, since its predicate is in fact contained in the essence of its subject. But it is not self-evident for us since this essence, the essence of God, is not known to us.