If facts, logic, and scientific procedures are all just arbitrarily "socially constructed" notions, then all that is left is consensus--more specifically peer consensus, the kind of consensus that matters to adolescents or to many among the intelligentsia.
Man's main task in life is to give birth to himself, to become what he potentially is. The most important product of his effort is his own personality.
If you're alive, you've got to flap your arms and legs, you've got to jump around a lot, you've got to make a lot of noise, because life is the very opposite of death.