Five "proofs" from 1265, courtesy of Brother Aquinas:
"The first and most obvious is based on change...anything changing is being changed by something else...This something else, if itself changing, is being changed by yet another thing; and this last by another. Now we must stop somewhere, otherwise there will be no first cause of the change, and as a result, no subsequent causes...We arrive then at some first cause of change not itself being changed by anything, and this is what everybody understands by 'god'."
"The second is based on the very notion of cause. In the observable world causes derive their causality from other causes; we never observe, nor ever could, something causing itself, for this would mean it preceeded itself, and this is not possible. But the deriving of causality must stop somewhere...So one is forced to suppose some first cause, to which everyone gives the name 'god'."
"The third way is based on what need not be and on what must be, and runs as follows. Some of the things we come across can be but need not be, for we find them springing up and dying away, thus sometimes in being and sometimes not. Now everything cannot be like this, for a thing that need not be, once was not; and if everything need not be, once upon a time there was nothing. But if that were true there would be nothing even now, because something that does not exist can only be brought into being, and nothing would be in being now, which contradicts observation. Not everything therefore is the sort of thing that need not be, some things must be, and these may or may not owe this necessity to something else. But just as a series of causes must have a stop, so also a series of things which must be and owe this to other things. One is forced to suppose something which must be, and owes this to nothing outside itself; indeed, it itself is the cause that other things must be."
"The fourth way is based on the gradation observed in things. Some things are better, truer, nore excellent than others. Such comparative terms describe varying degrees of approximation to a superlative; for example things are hotter and hotter the nearer they approach what is hottest. Something therefore is the truest and best and most excellent of things, and hence the most fully in being; for Aristotle says that the truest things are the things most fully in being. Now when many things possess some property in common, the one most fully possessing it causes it in the others; fire, as Aristotle says, the hottest of all things, causes all other things to be hot. Something therefore causes in all other things their being, their goodness, and whatever other perfection they have. And this is what we call 'god'."
The fifth way is based on the guidedness of nature. Goal-directed behaviour is observed in all bodies obeying natural laws, even when they lack awareness. Their behaviour hardly ever varies and practically always turns out well, showing that they truly tend to goals and do not merely hit them by accident. But nothing lacking awareness can tend to a goal except it be directed by someone with awareness and understanding; the arrow for example requires an archer. Everything in nature therefore is directed to its goal by someone with understanding, and this we call 'god'." |
