What is clear is that Parmenides is making a conscious attempt at some kind of a new start. Like Descartes, he is trying to find an unassailable starting-point on which something further can be built. This search is understandable, given the intellectual situation of the time. The principles of the Milesians had yielded no one clearly true system, but a number of rival ones — in itself a scandal. Heraclitus had made the whole of cosmology suspect by revealing deep-seated contradictions at its heart. In the background, the Pythagoreans were directly or indirectly stimulating new lines of thought and using them, perhaps, for their own mysterious purposes.