arguments in favor of the existence of God

as always, we need a little historic background.

1. the scholastic philosophers of the middle ages used deductive arguments to prove the existence of God, but they didn't do it in the way we do it today. in the middle ages most -if not ALL- people believed in the existence of God. the arguments were supposed to add reasons to your (already existing) beliefs. it was a didactic exercise in reasoning more than a response to a counterargument.

2. I must remind you that in a deductive argument you don't need to speak of existence SOLELY as an empirical property. here's a definition of existence.

DEF: a, b, c... exist if they exist and have properties f-ness, g-ness, and h-ness independent of anyone’s beliefs, linguistic practices, conceptual schemes, and so on.

if you want a good example of something that exists independently of our beliefs about it look no further than math itself. so, for instance:

every natural number greater than 1 is either a prime itself or can be factorized as a product of primes.

is independent of our beliefs.
__________

Aquinas cosmological argument (cause/effect)

1- There are things that are caused by other things.
2- Nothing can be the cause of itself.
3- There cannot be an infinite regress of objects causing other objects to exist.
Therefore, there must be an uncaused first cause, called God.

Analysis: 2- goes back to Parmenides' point "nothing comes from nothing", meaning that a cause needs a previous cause, which is true. 3- now Aquinas discards infinite regress, He's appealing to a principle in physics, which is complex enough. His conclusion is axiomatic, the uncaused cause is GOD. 

Counter from Hume: For Hume there is no problem of imagining an infinite series of cause/effect. In other words, there is no beginning to the universe. Brian Greene inflation: Hume's idea brings us to the idea of 9 types of INFLATION, defended by physicist Brian Greene from Columbia University, in this scenario, there are different pockets in which inflation fields collapse and form new universes. In other words, universes come and go creating a permanent self-contained inflation.

Anselm's Ontological argument (aprioristic)1- God is by definition the greatest being possible.
2- Suppose that most perfect being exists only in the mind.
3- Let's agree that a being that exists in the mind and in reality is greater than a being that exists only in the mind.
4- If God exists only in the mind, we can imagine something greater than God (the greatest possible being that we established by hypothesis existing in reality).
5- But we cannot imagine something that is greater than God (we can be confident that God exists, because we know that a being that can be conceived and actually exists is greater than a being that merely can be conceived but does not exist. 

Therefore, God exists. 

Analysis: Anselm is appealing to an a priori deductive argument.

1- is true. 2- simply advances a hypothesis of existence only in the mind. 3- remember that SOLELY existing in the mind means that the most perfect may not exist in reality. 4- makes the obvious point that existing in reality is more perfect than not existing. now 5 takes us to a contradiction. The conclusion simply states that a being that can be conceived and actually exists is greater than a being that merely can be conceived but does not exist.

Gaunilo's counter to Anselm: click here for Gaunilo's counter to Anselm.

Decartes argument:

1. God by definition possesses all possible perfections.
2. Existence is a perfection.
Therefore: God exists. 

Pascal's wager (statistical argument)

1- God is, or God is not.
2- Reason cannot decide between the two alternatives.
3- Let's weigh the gain and the loss in wagering that God is.
4- If you gain, you gain all; if you lose, you lose nothing.
Wager, then, without hesitation that HE IS.

Counter to Pascal: Pascal's wager has been attacked from theists. In the sense that believing in God for the sake of probabilities is a demoted form of belief. Faith cannot be negotiated in the manner Pascal prescribes it.