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.
Knowledge forbidden? Suspicious, reasonless. Why should their Lord Envy them that? Can it be sin to know, Can it be death? And do they only stand By ignorance? Is that their happy state, The proof of their obedience and their faith? O fair foundation laid whereon to build Their ruin!
There is nothing so charming as the knowledge of literature; of that branch of literature, I mean, which enables us to discover the infinity of things, the immensity of Nature, the heavens, the earth, and the seas; this is that branch which has taught us religion, moderation, magnanimity, and that has rescued the soul from obscurity; to make her see all things above and below, first and last, and between both; it is this that furnishes us wherewith to live well and happily, and guides us to pass our lives without displeasure and without offence.
Go out of the house to see the moon, and 't is mere tinsel; it will not please as when its light shines upon your necessary journey. The beauty that shimmers in the yellow afternoons of October, who could ever clutch it? Go forth to find it, and it is gone: 't is only a mirage as you look from the windows of diligence.
For myself, I like a universe that, includes much that is unknown and, at the same time, much that is knowable. A universe in which everything is known would be static and dull, as boring as the heaven of some weak-minded theologians. A universe that is unknowable is no fit place for a thinking being. The ideal universe for us is one very much like the universe we inhabit. And I would guess that this is not really much of a coincidence.
[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 suppression of uncomfortable ideas may be common in religion or in politics, but it is not the path to knowledge; it has no in the endeavor of science. We do not know in advance who will discover fundamental insights.
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.
Lastly, I would address one general admonition to all: that they consider what are the true ends of knowledge, and that they seek it not either for pleasure of the mind, or for contention, or for superiority to others, or for profit, or fame, or power, or any of these inferior things: but for the benefit and use of life; and that they perfect and govern it in charity.