These two Greeks are said to have defined what amounts to the whole of philosophy so that all subsequent philosophy has largely been commentary on MrPlato and MrAristotle. They deserve to be considered the founders of software in an extended sense since: 1) MrPlato is the source of Idealism which is that ideas and forms are real--that's what we do as software people--and 2) MrAristotle is the father of logic. So I think they deserve pride of place.
-- RaySchneider
However, the syllogism, essential to Aristotle's theory, doesn't play a very special role in modern logic theory. It has indeed been claimed that MrAristotle's theory, being undisputed for centuries, was more a hindrance than a help to the development of modern theory about propositional calculus and predicate calculus. Of course, this isn't so much MrAristotle's fault as well the fault of the people who took his word as infallible. (Mainly the Scholastici).
What are you talking about? The key idea that logic is something that can be formalized is core to all modern logic theory, and the syllogism was the first step in that direction. There are studies that show PreliterateCivilizations? can't do syllogisms properly. MrAristotle pointed us in the right direction, even if he made some mistakes.
Not covered by these two: what is the interface between the continuous, Platonic realm of geometry with the discrete, real world of integers? Physics does it out of convenience when it uses pi but it doesn't understand why it works so well (that is, why mathematics works so well to describe physics). See SquareRootOfTwo. -- MarkJanssen