“(…) All kind of experience may come to you – remain unmoved in the knowledge that all perceivable is transient, and only ‘I am’ endures.”

"The Making of a Scientist," p. 11: video http://www.youtube.com/watch?v=NEwUwWh5Xs4&t=26s
What Do You Care What Other People Think? (1988)
Context: I have a friend who's an artist, and he sometimes takes a view which I don't agree with. He'll hold up a flower and say, "Look how beautiful it is," and I'll agree. But then he'll say, "I, as an artist, can see how beautiful a flower is. But you, as a scientist, take it all apart and it becomes dull." I think he's kind of nutty. … There are all kinds of interesting questions that come from a knowledge of science, which only adds to the excitement and mystery and awe of a flower. It only adds. I don't understand how it subtracts.

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 101.

Variant: Because I knew even then how rare that kind of love is. Only the luckiest people get to experience it at all.
Source: The Best of Me

Source: Tatiana and Alexander

Letter to Jean Cruveilhier (1837), as quoted by William Coleman, Death is a Social Disease: Public Health and Political Economy in Early Industrial France (1982)

Source: First and Last Things: A Confession of Faith and Rule of Life http://www.gutenberg.org/etext/4225 (1908), Ch. 4, sect. 6, The Last Confession

The New Hugo Winners: Award-winning Science Fiction Stories Vol. 1 (1989)<!-- Afterword to "Speech Sounds" -->, p. 215
General sources
Context: We are meant to know, or we are amoebae.
Suppose that we are wise enough to learn and know — and yet not wise enough to control our learning and knowledge, so that we use it to destroy ourselves?
Even if that is so, knowledge remains better than ignorance. It is better to know — even if the knowledge endured only for the moment that comes before destruction — than to gain eternal life at the price of a dull and swinish lack of comprehension of a universe that swirls unseen before us in all its wonder. That was the choice of Achilles, and it is mine, too.