Aquinas's+Cosmological+Argument

=The First Way – From Motion – The unmoved mover=

It is certain, and evident to our senses, that in the world some things are in motion. Now whatever is moved is moved by another…It is therefore impossible that in the same respect and in the same way a thing should be both mover and moved….If that by which it is moved be itself moved, then this must also be moved by another…But this cannot go on to infinity because then there would be no first mover, and, subsequently, no other move.

Therefore it is necessary to arrive at a first mover, moved by no other; and this everyone understands to be God.

=The Second Way – From Cause – The uncaused causer=

The Second Way is from the nature of efficient cause. In the world of sensible things we find there is an order of efficient causes. There is no case known (neither is it indeed possible) in which a thing is found to be the efficient cause of itself; for so it would be prior to itself, which is impossible.

Therefore it is necessary to admit to a first efficient cause, to which everyone gives the name of God.

=The Third Way – From Necessity and Contingency=

The third way is taken from possibility and necessity…We find in nature things that are possible to be and not to be, since they are found to be generated, and to be corrupted, and consequently, it is possible for them to be and not to be. Therefore if everything can not be, then at one time there was nothing in existence and it would have been impossible for anything to have begun to exist and thus even now nothing would be in existence, which is absurd.

=Conclusion:=

Therefore we cannot but admit the existence of some being having of itself its own necessity, and not receiving it from another, but rather causing in others their necessity. This all men speak of as God.

=Explanation:=

We see that things which lack intelligence, such as natural bodies, act for an end, and this is evident from their acting always, or nearly always, in the same way, so as to obtain the best result. Trees, dogs, mountains etc. all work towards an end. Trees give out oxygen and grow, dogs seek out and eat food and breed, mountains are complex eco-systems. All the things on earth work together and separately for their own benefit and for the benefit of the planet as a whole, and follow fixed natural (scientific) laws. Hence it is plain that not fortuitously, but designedly, do they achieve their end. Everything achieves its end. Dogs get food, trees grow etc. the laws of science work in such a way that everything functions properly, and this can’t be down to chance, but instead has to have been designed.

Now whatever lacks intelligence cannot move towards an end, unless it be directed by some being endowed with knowledge and intelligence; as the arrow is shot to its mark by the archer. If you don’t have intelligence (i.e. you’re a dog, a tree or a mountain) you can’t deliberately choose to reach your end, it takes someone with intelligence to direct it towards its end. Another way of putting this would be to say that natural laws (scientific laws) govern the world and lead to all things reaching their ends, and natural laws couldn’t randomly lead to all things achieving their end.

Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God. Therefore there must be an intelligent being who directs the laws of science to allow things to reach their end.