The philosophical figures we study in the history of ancient thought are not a random collection. There
is a unified progression through the Presocratics, Socrates, Plato, Aristotle, the Stoics, and the Neoplatonists. They
all develop philosophy as a way of knowing and as a way of life dedicated to knowing. They all recognize the being,
the intelligibility, and the good of things. These thinkers do not all say exactly the same things; each of them brings
out aspects that others may have neglected, but even as they bring out something original they usually let something
else slide into obscurity; gains are accompanied by losses. This is the grand narrative of classical philosophy. Over
against this narrative, however, we can also discern counter-philosophical pressures, ways of thinking that counteract
philosophy and question its very possibility, and these counter-philosophical positions are not just Greek and Roman
but perennial. They are as enduring as philosophy itself. Two of the most prominent “non-philosophies” of the
ancient world are reductive atomism, found in the original Democritean atomists and in the Epicureans; and
sophistry and historicism, found in the original sophists. The atomists were a kind of scientific substitute for
philosophy, while the sophists represented a historicist or relativistic alternative. Philosophy always has to define
and defend itself against these two opposing forces. The struggle to do so is endemic to the human condition.
Because there is such a thing as philosophy, there also are counterfeits that are played off against it, things that only
look like or claim to be philosophy.
--Robert Sokolowski, "Husserl on First Philosophy"