Conversation so far:
What is Epistemology?
In the field of epistemology, Putnam is known for his "brain in a vat" thought experiment (a modernized version of Descartes's evil demon hypothesis).
What was Putnam's "brain in a vat" experiment?
if some person, Mary, were a "brain in a vat", whose every experience is received through wiring and other gadgetry created by the "mad scientist.
What did the experiment prove?
Putnam has clarified that his real target in this argument was never skepticism, but metaphysical realism.
How did it explain metaphysical realism?
such a scenario is impossible, attempts to show that this notion of a gap between man's concept of the world and the way it is, is in itself absurd.
When was this experiment performed?
CANNOTANSWER.
Was this experiment done on humans?
CANNOTANSWER.

Question: What else was notable about epistemology?
Self-contained rewrite: Besides Hilary Putnam's "brain in a vat" experiment, what else was notable about epistemology?