Plato, as regards his method of thought, was a strict and determined transcendentalist.  He declared philosophy to be the science of unconditioned being, and asserted that this was known to the soul by its intuitive reason, which is the organ of all philosophic insight.  The reason perceives substance, the understanding only phenomena.  Being [Greek:  to on], which is the reality in all actuality, is in the ideas or thoughts of God; and nothing exists or appears outwardly, except by the force of this indwelling idea.  The WORD is the true expression of the nature of every object; for each has its divine and natural name, beside its accidental human appellation.  Philosophy is the recollection of what the soul has seen of things and their names.

The life and essence of all things is from God.  Plato’s idea of God is of the purest and highest kind.  God is one, he is Spirit, he is the supreme and only real being, he is the creator of all things, his providence is over all events.  He avoids pantheism on one side, by making God a distinct personal intelligent will; and polytheism on the other, by making him absolute, and therefore one.  Plato’s theology is pure theism.[250]

Ackermann, in “The Christian Element in Plato,"[251] says:  The Platonic theology is strikingly near that of Christianity in regard to God’s being, existence, name, and attributes.  As regards the existence of God, he argues from the movements of nature for the necessity of an original principle of motion.[252] But the real Platonic faith in God, like that of the Bible, rests on immediate knowledge.  He gives no definition of the essence of God, but says,[253] “To find the Maker and Father of this All is hard, and having found him it is impossible to utter him.”  But the idea of Goodness is the best expression, as is also that of Being, though neither is adequate.  The visible Sun is the image and child of the Good Being.  Just so the Scripture calls God the Father of light.  Yet the idea of God was the object and aim of his whole philosophy; therefore he calls God the Beginning and the End;[254] and “the Measure of all things, much more than man, as some people have said” (referring to Protagoras, who taught that “man was the measure of all things").  So even Aristotle declared that “since God is the ground of all being, the first philosophy is theology”; and Eusebius mentions that Plato thought that no one could understand human things who did not first look at divine things; and tells a story of an Indian who met Socrates in Athens and asked him how he must begin to philosophize.  He replied that he must reflect on human life; whereupon the Indian laughed and said that as long as one did not understand divine things he could know nothing about human things.

There is no doubt that Plato was a monotheist, and believed in one God, and when he spoke of gods in the plural, was only using the common form of speech.  That many educated heathen were monotheists has been sufficiently proved; and even Augustine admits that the mere use of the word “gods” proved nothing against it, since the Hebrew Bible said, “the God of gods has spoken.”