In metaphysics, Plato's beard is a paradoxical argument dubbed by Willard Van Orman Quine in his 1948 paper "On What There Is".
[1] Quine defined Plato's beard – and his reason for naming it so – in the following words: This is the old Platonic riddle of nonbeing.
This tangled doctrine might be nicknamed Plato's beard; historically it has proved tough, frequently dulling the edge of Occam's razor.
[2] The argument has been favored by prominent philosophers including Bertrand Russell, A. J. Ayer and C. J. F.
"Only if Plato's beard is sufficiently tough, and tangled by many entities, can it be worth our while to use Ockham's razor.