Philisophical Proof Of God

The following is from the works of St Thomas Aquinas:

The first and most obvious way (to prove that God exists and is omnipotent) is the argument from motion. It is certain and evident to our senses that things are in motion in this world. Everything that moves is moved by something else, for nothing can move unless it has the potentiality of acquiring the perfection of that towards which it moves. To move something is to act, since to move is to make actual what is potential. Now nothing can be changed from a state of potentiality to actuality except by something that itself is in a state of actuality. A fire that is actually hot makes wood that is potentially hot become actually hot, and so moves and changes it. Now it impossible for the same thing to both in actuality and potentiality at the same time and in the same respect- only in different respects. What is actually hot cannot at the same time be potentially hot, though it is potentially cold. Therefore it is impossible for something to be both the mover and the thing moved in the same way, or for it to move itself. Therefore everything that moves must be moved by something else. If that by which it is moved also moves, it must itself be moved by something else and that by something else again. But things cannot go on forever because then there would be no first mover, and consequently no subsequent mover since intermediate things move only from the motion they receive from the first mover- just as a staff moves only because it is moved by a hand. Therefore it is necessary to go back to some first mover who is not moved by anyone, and this everyone understands as God.

The second way is from the nature of an efficient cause. In the world of the senses we find there is a sequence of efficient causes, but we never find something that causes itself, and it is impossible to do because it would precede itself- which is impossible. Now the series of finite causes cannot go on to infinity because in every series of causes the first cause is the cause of the intermediate cause and the intermediate causes cause the last cause, weather the intermediate causes are many or only one. However if you take away a cause you also take away its effect. If there is no first cause among the efficient causes, there will be no last or intermediate cause. But if we proceed to infinity in the series of causes there will be no first cause and therefore no final or intermediate effects would exist- which is obviously not true. Thus it is necessary to posit some first efficient cause which all men call God.

The second proof is very similar to the first, using causes and effects rather than motion to describe essentially the same thing. Also: Following Aristotle, Metaphysics: Aquinas has a broader notion of causality than does modern philosophy. A thing's matter, form , and purpose he calls, respectively, its material cause, formal cause, and final cause, while what we call a cause, Thomas calls an 'efficient cause'.

The third way is based on what can exist (possibility) and what must exist (necessity). It is the following: We find things in nature that can exist or not exist, since things are found to come into existence (be generated) and cease to exist (be corrupted) and therefore it is possible for them to exist or not to exist. Now it is impossible for such things always to have existed, for if it is possible for something not to exist, at some time it did not exist. Therefore if it is possible for everything not to exist, at one time nothing was in existence. But if this was true, then nothing would exist even now, since that which does not exist only begins to exist through something else that is in existence. But if nothing was in existence it was impossible for anything to begin to exist, and so nothing would exist now- which is obviously not true. Everything cannot be [merely] possible but there must be some necessary being in existence. Something is a necessary being either as a result of the action of another or not. However it is impossible to go on into infinity in [the series of] necessary beings that must exist because they are called by another, as we have already proved above in the case of efficient causes. We must therefore posit a [necessary] being that must exist in itself and does not owe its existence to anything else, but is the reason that other things must be. This being we call God.

The fourth way is based on the gradations that exist in things. We find in the world that some things are more or less true, or good, or noble and so on. The description of "more" or "less" is given to things to the degree that they approach the superlative in various ways. For example a thing is said to be hotter as it approaches more closely what is hottest. Therefore there is something that is the most true, and best, and most noble, and consequently most fully in being, for the things that are the greatest in truth are the greatest in being, as is said in the Metaphysics (by Aristotle). Now the superlative in any classification (or genus) is the cause of all the things in that classification. Fire, for example, which is the hottest of all things is the cause of everything that is hot, as is said in the same book (metaphysics). Therefore there is something that is the cause of being and goodness and whatever perfection everything has, and this we call God.

The fifth way is based on the order in the universe. We see that things that lack consciousness such as bodies in nature function purposively. This is evident from the fact that they always, or nearly always, function in the same way so as to achieve what is best. Therefore it is evident that they achieve their end, not by chance but by design. But things that do not possess consciousness tend towards an end only because they are directed by a being that possesses consciousness and intelligence, in the same way that an arrow must be aimed by an archer. Therefore there is an intelligent being who directs all things to their goal, and we say that this is God.