Before I built a wall I'd ask to know What I was walling in or walling out, And to whom I was like to give offence. Something there is that doesn't love a wall, That wants it down.
Man, being the servant and interpreter of Nature, can do and understand so much and so much only as he has observed in fact or thought of the course of nature; beyond this he neither knows anything nor can do anything.
What we know is not capable of being otherwise; of things capable of being otherwise we do not know, when they have passed outsideour observation, whether they exist or not. Therefore the object of knowledge is of necessity. Therefore it is eternal; for things that are of necessity in the unqualified sense are all eternal; and things that are eternal are ungenerated and imperishable.
Thoughts without content are empty, intuitions without concepts are blind... The understanding can intuit nothing, the senses can think nothing. Only through their union can knowledge arise.
For the purpose of knowledge we must know how to make use of the inward current which draws us towards a thing, and also of the current which after a time draws us away from it.