The ontological argument in essence attempts to prove the existence of God by an analysis of the idea or notion of Him. The common form of the ontological argument goes like this.
“God is truly understood to be the being than which a greater cannot be thought of. But a being who exists in reality and not merely as an object of thought is greater than a being who exists merely in the mind. Hence, if God did not exist actually outside the mind, He would not be that than which nothing greater can be thought of. Therefore, God exists in reality and not merely in our minds.”
The first, and best-known, ontological argument was proposed by St. Anselm of Canterbury in the 11th. Century A.D. In his Proslogion, St. Anselm claims to derive the existence of God from the concept of a being than which no greater can be conceived. St. Anselm reasoned that, if such a being fails to exist, then a greater being — namely, a being than which no greater can be conceived, and which exists — can be conceived. But this would be absurd: nothing can be greater than a being than which no greater can be conceived. So a being than which no greater can be conceived — i.e., God — exists
Descartes utilized the ontological argument throughout his works. His proof runs like this: “When one says that something is contained in the nature or concept of a thing, thereby affirms that this something belongs in truth to that thing, is true of it. But the necessary existence of God is contained in the idea of God. Therefore, it is true to say of God that necessary existence is in Him, that is, that He exists.”
Leibniz’ ontological argument goes like this: “It is possible for God to exist, since that does not involve contradiction. But if God is possible, He must exist, since a God who is merely possible is not that which is understood by the concept ‘God.’ Therefore, God really exists.”
The cosmological argument is another way of arguing for the existence of God. It is also known as the first cause argument for the existence of God. There are three versions of this argument: the argument from causation in esse, the argument from causation in fieri, and the argument from contingency.
St. Thomas Aquinas, the most famous philosopher of the Middle Ages adapted an argument he found in his reading of Aristotle to form one of the earliest, and the most influential versions of the cosmological argument. The cosmological argument does not attempt to prove other attributes about God. Scholastic philosophers believed however further arguments can be used to prove to anyone via logic some attributes of God, such as his omniscienice, simpleness (or total lack of composition), and more. However, they believed other things can not be known about God by deduction and can only be known by divine revelation, such as that God is a trinity.
Framed as a formal proof, the first cause argument can be stated as follows: 1. Things are caused. 2. Nothing can cause itself. 3. Therefore, everything that is caused is caused by something other than itself. 4. A causal chain cannot stretch infinitely backward in time. 5. If the causal chain cannot stretch infinitely backward in time, there must be a first cause. 6. Therefore, everything that is caused has a first cause, i.e. God influential versions of the cosmological argument. The cosmological argument does not attempt to prove other attributes about God. Scholastic philosophers believed however further arguments can be used to prove to anyone via logic some attributes of God, such as his omniscience, simple ness (or total lack of composition), and more. However, they believed other things can not be known about God by deduction and can only be known by divine revelation, such as that God is.
The greatest work of Thomas was the Summa and it is the fullest presentation of his views, it has three parts, Part one. treats of God, who is the "first cause, himself uncaused" (primum movens immobile) and as such existent only in act (actu), that is pure actuality without potentiality and, therefore, without corporeality. His essence is actus purus et perfectos. This follows from the fivefold proof for the existence of God; namely, there must be a first mover, unmoved, a first cause in the chain of causes, an absolutely necessary being, an absolutely perfect being, and a rational designer. In this connection the thoughts of the unity, infinity, unchangeableness, and goodness of the highest being are deduced.
p.s
I have read critique on the work of these philosophers and I have copied a few parts relevant to your query, if you are interested to read more I can send you a book also.as an aside, all arguments for god, cosmological, teleological and ontological have severe limitations, and eventually fail to make the case they try to make
I m v thankful 2 U :)
U have made it easy nd clear as 5 reasons by Aquinas
U r right their Argumnts didnt make them Successful
Wa Alaikum Assalam
Why go so far back to "old" Books......................
Look at what is happening at present.....................
The First Election after 9/11...........
A poor Muslims' Son becomes President of the most Powerful Nation on Earth.................Proof enough don't you think!
lol Obama Obama
I m Muslim and i knw God Exists
but i m studying Philosophy and reading these Argumnts thats y came here 4 help.