Every way of classifying a thing is but a way of handling it for some particular purpose.

The bottom of being is left logically opaque to us, as something which we simply come upon and find, and about which if we wish to act we should pause and wonder as little as possible.

Pretend what we may, the whole man within us is at work when we form our philosophical opinions.

That nature will follow to-morrow the same laws that she follows to-day is, they all admit, a truth which no man can know; but in the interests of cognition as well as of action we must postulate or assume it.