But the universe to the eye of the human understanding is framed like a labyrinth; presenting as it does on every side so many ambiguities of way, such deceitful resemblances of objects and signs, natures so irregular in their lines, and so knotted and entangled.

And then the way is still to be made by the uncertain light of the sense, sometimes shining out, sometimes clouded over, through the woods of experience and particulars; while those who offer themselves for guides are (as was said) themselves also puzzled, and increase the number of errors and wanderers.

In circumstances so difficult neither the natural force of man's judgment nor even any accidental felicity offers any chance of success.

No excellence of wit, no repetition of chance experiments, can overcome such difficulties as these.

Our steps must be guided by a clue, and the whole way from the very first perception of the senses must be laid out upon a sure plan.