That would be Anselm of Cantebury!
Anselm Archbishop of Canterbury 1100s i think
The ontological argument of the exsitance of god is supported by abrahmic religions. It is not widely practiced in the current day.
The ontological argument is a deductive argument. It aims to prove the existence of God based on the concept of God as a necessary being. It uses logical reasoning to demonstrate that the existence of God is a necessary consequence of the definition of God as a perfect being.
The ontological argument is a philosophical argument for the existence of God that is based on the concept of existence or being. It suggests that the very concept of God being the greatest possible being necessarily implies his existence. This argument has been presented and debated by various philosophers throughout history, such as Anselm of Canterbury and René Descartes.
The ontological argument posits that the concept of God as a perfect being necessitates His existence. It argues that if we can conceive of a being that possesses all perfections (including existence), then that being must exist in reality. Critics argue that existence is not a property that adds to the perfection of a being and that the argument relies heavily on the assumption that existence is a predicate.
Aquinas critiques the ontological argument, stating that it is not possible to deduce the existence of God from the concept of a perfect being alone. He argues that we cannot know God's existence simply through reason or definition, but must rely on faith and revelation.
St. Anselm of Canterbury is often considered the founder of Scholasticism. He was a medieval theologian and philosopher known for his writings on the relationship between faith and reason, particularly his ontological argument for the existence of God.
There are many options for books on ontological arguments at Amazon, including The Many-Faced Argument: Recent Studies on the Ontological Argument for the Existence of God. Barnes and Noble and Borders also offer a selection.
Descartes's major work is Meditations on First Philosophythe third of which deals with the existence of God as an 'effect'Rene' Descartes was a mathematician and idealist philosopher. His major impact on philosophy and religion was his ontological proof of the existence of God.
The first philosopher to propose an ontological argument is still up for debate. Some think that Greek philosophers, such as Plato, first argued it. The mainstream view is that the ontological argument was first developed by St. Anselm. Others believe that the Islamic philosopher Avicenna was the first, and may others view the philosopher Descartes as being the first.
The philosopher, Immanuel Kant attempted to show how philosophy could prove the existence of God. Kant rejected the ontological, teleological and cosmological arguments for the existence of God but held that God's existence is a necessary presupposition of there being any moral judgments that are objective, that go beyond mere relativistic moral preferences; such judgments require standards external to any human mind-that is, they presume God's mind. This is a powerful point of view, but assumes that humans are incapable of morality unless God exists. If we reverse that argument, we find that Kant, having rejected the ontological, teleological and cosmological arguments, leaves us no good reason to believe in the existence of God.
Descartes argues for the existence of God through his ontological argument, which posits that the idea of a perfect being must come from a perfect being (God). He also argues that since he (Descartes) has a clear and distinct idea of God, and God is a necessary being, then God must exist in reality. This reasoning forms the basis for Descartes' belief in the existence of God.