No More Learning

Supposing that nothing else is "given" as real but our world of
desires and passions, that we cannot sink or rise to any other "reality"
but just that of our impulses--for thinking is only a           of these
impulses to one another:--are we not permitted to make the attempt and
to ask the question whether this which is "given" does not SUFFICE, by
means of our counterparts, for the understanding even of the so-called
mechanical (or "material") world?