If almost nothing the Cārvākas wrote survives, how do we know what they thought?
Its coordinates: 2.2 Sources of Knowledge · 2.2.2 Reason and Intuition
I've been reading about the Cārvāka or Lokāyata school, the Indian materialists, and every introduction says something like "almost no Cārvāka text survives; the school is reconstructed from the summaries its opponents wrote."
As someone who studies texts, this worries me. If everything we know comes from people who were trying to refute them, how can we trust the picture? Isn't it a bit like knowing a poet only through the reviews of rivals?
What are the actual sources, and how do scholars decide what the Cārvākas really held?