Arthur Schopenhauer,
The World as Will and Representation…
“ I have already ex plained above how abstract knowledge often unites a variety of intuitive cognitions in one form or one concept in such a way that they can no longer be distinguished; therefore abstract knowledge stands to intuitive knowledge as the shadow to the real objects, the great multiplicity of which it presents through one outline comprehending them all. Now the pretended principle of the reason makes use of this shadow. ”
