Upon the solution of this problem, or upon sufficient proof of the impossibility of synthetical knowledge a priori, depends the existence or downfall of metaphysics.
We can't expect to solve problems if all we do is tear each other down. You can disagree with a certain policy without demonizing the person who espouses it.
The leftist is anti-individualistic... He is not the sort of person who has an inner sense of confidence in his own ability to solve his own problems and satisfy his own needs.