For either this was psychology in the positive sphere and spoke of human beings as the functioning subjects, in which case it presupposed the ground of the world and moved in a circle; or it actually put this ground in question, as did Hume who in this respect was much more radical than Kant in which case it plunges us into a paradoxical solipsism and skepticism and, in any case, into a horrid situation where the being of the world is incomprehensible.