In Philosophy, the contemplations of man do either penetrate unto God, or are circumferred to Nature, or are reflected and reverted upon himself. Out of which several inquiries there do arise three knowledges, Divine Philosophy, Natural Philosophy, and Human Philosophy or Humanity. For all things are marked and stamped with this triple character of the power of God, the difference of Nature and the use of Man.
If I had an hour to solve a problem and my life depended on the solution, I would spend the first 55 minutes determining the proper question to ask, for once I know the proper question, I could solve the problem in less than five minutes.
[Misquotation; not by Einstein.] If only I had known, I should have become a watchmaker. [Apparently remorseful for his role in the development of the atom bomb.]
The true bounds and limitations, whereby human knowledge is confined and circumscribed,... are three: the first, that we do not so place our felicity in knowledge, as we forget our mortality: the second, that we make application of our knowledge, to give ourselves repose and contentment, and not distates or repining: the third, that we do not presume by the contemplation of Nature to attain to the mysteries of God.
Our knowledge springs from two fundamental sources of the mind; the first is the capacity of receiving representations (receptivity for impressions), the second is the power of knowing an object through these representations (spontaneity [in the production] of concepts).
But the best read naturalist who lends an entire and devout attention to truth, will see that there remains much to learn of his relation to the world, and that it is not to be learned by any addition or subtraction or other comparison of known quantities, but is arrived at by untaught sallies of the spirit, by a continual self-recovery, and by entire humility.
Knowing things halfway is a greater success than knowing things completely: it takes things to be simpler than they really are andso makes its opinions more easily understandable and persuasive.