The Pre-Socratics were the first philosophers of science. They were known as the sophos (the wise ones). They were ecliplised by the British and German philosophers of science in the seventeenth century and were largely disconnected from science hence forth. Science sets the agenda, but philosophers bring philosophical reasons instead of scientific reasons. Science answers the questions. The Pre-Socratics were the first to deal with metaphysics and did so to provide a rational philosophy. This allowed for a rational and objective observation and the use of reason to systematize and order the content to make it coherent.
The Sophists were worldly-wise in contrast with the sophos–frustrated by the plurality of answers in the current philosophy. The Sophists were the original skeptics as evidenced in Pyrrho. They came out of the sixth century BC and broke away from religious dogma, which had never happened before. Their methods were pragmatic and subjective–rhetorical and fashionable. The phrase, “The One and the Many” became important. The One (reality) had everything related to it (Many). This is where we get Monism–the quality of oneness. We see Monism appear later in Leibniz’s monads, which take us to a single substance and leads to atomic theory.