"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe." 

-Albert Einstein

Attributed: Ego, Hunger, and Aggression: a Revision of Freud’s Theory and Method by Frederick S. Perls

The old saying of the two kinds of truth. To the one kind belongs statements so simple and clear that the opposite assertion obviously could not be defended. The other kind, the so-called 'deep truths', are statements in which the opposite also contains deep truth. 

-Niels Bohr

 'Discussion with Einstein on Epistemological Problems in Atomic Physics', in P. A. Schilpp (ed.), Albert Einstein: Philosopher-Scientist (1949), 240.

"To understand God's thoughts, one must study statistics, for these are the measure of His purpose."

-Florence Nightingale

Adapted in: The Life, Letters and Labours of Francis Galton (1924), Vol 2, 415

"Science, for me, gives a partial explanation for life. In so far as it goes, it is based on fact, experience and experiment."

-Rosalind Franklin

Excerpted in Brenda Maddox, The Dark Lady of DNA (2002), 61

“The saddest aspect of life right now is that science gathers knowledge faster than society gathers wisdom.” 

― Isaac Asimov

"Isaac Asimov's Book of Science and Nature Questions" (New York: Weidenfeld & Nicolson, 1988), p. 281.

"Pierre Curie, a brilliant scientist, happened to marry a still more brilliant one—Marie, the famous Madame Curie—and is the only great scientist in history who is consistently identified as the husband of someone else."

-IssacAsimov

View from a Height (1963), pg 119

"I often use the word serendipity because I believe that in order for coincidences to happen, the process leading up to it is very important"

-Sumio Iijima

About myself, To the younger generation, in Innovative Engine, column for NEC researchers, Sep.25, 2007

"Nothing in life is to be feared, it is only to be understood."

-Marie Curie

 'Need We Fear Our Nuclear Future?', Bulletin of the Atomic Scientists (Jan 1968), 24

“Somewhere, something incredible is waiting to be known.” 

― Carl Sagan

Frequently attributed but actually from an editorial line from a Newsweek interview

“If we knew what it was we were doing, it would not be called research, would it?” 

― Albert Einstein

Attributed, unknown origin

In fact, it is often stated that of all the theories proposed in this century, the silliest is quantum theory. Some say that the only thing that quantum theory has going for it, in fact, is that it is unquestionably correct. 

— Michio Kaku

Hyperspace: A Scientific Odyssey Through Parallel Universes, Time Warps, and The Tenth Dimension (1994) pg 262

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