I have started reading Anselm; interesting stuff. Not sure I’ve really got my head round it yet, but nevertheless let me try to paraphrase my understanding of his argument so far in a modern context:
We are all aware that there are ‘non-material’ things: love, justice, purpose, hope, belief, to name a few. An act of love is carried-out through ‘love’, and an act of justice is carried-out through ‘justice’. If love did not exist then one could not carry-out an act of love. And it is through ‘goodness’ that we are able to carry-out an act of love; without goodness we could not carry-out an act of love, or of justice, or… Apart from goodness, all other non-material things are carried-out through goodness, and therefore goodness is the ultimate non-material thing, or ‘essence’ and it exists through itself.
We can also perceive that some acts are express more love than others; there can be great love, or great justice, or great goodness. And we can imagine that for any great goodness there could be a goodness that is just a little greater … until we reach infinite goodness. And so everything that is good in any way is within that infinite, or supreme goodness.
Everything exists through something, and we have seen that of things immaterial everything exists through supreme goodness. But everything must exist through one thing. If we imagine that there were more than one thing, then either there would be one thing through which the more than one thing were able to exist – which would then be the one thing, or they might exist through a ‘power to exist through oneself’ – which would then be the one thing, or they would exist mutually through each other – which defies reason.
The universe exists, and so it exists through something. Non-material things exist, and they exist through supreme goodness. Therefore either the universe exists through supreme goodness, or supreme goodness exists through the universe. But can supreme goodness exist through the universe? We can conceive that there are other universes, but it is inconceivable that those other universes exist without supreme goodness; being non-material supreme goodness cannot be constrained within a material context. Therefore it is impossible that supreme goodness exists through the universe, but the universe must exist through supreme goodness, and there can only be one supreme goodness – which we define as God.