“Man thinks that by thinking he will solve all the secrets of the universe. He forgets that he cannot possibly put the entire ocean into a bucket.”
Related quotes

“The secret of the man who is universally interesting is that he is universally interested”
Literary Friends and Acquaintance : A Personal Retrospect of American Authorship (1900) http://archive.org/stream/oliverwendellhol03395gut/old/whowh10.txt
Context: The secret of the man who is universally interesting is that he is universally interested, and this was, above all, the secret of the charm that Doctor Holmes had for every one. No doubt he knew it, for what that most alert intelligence did not know of itself was scarcely worth knowing. This knowledge was one of his chief pleasures, I fancy; he rejoiced in the consciousness which is one of the highest attributes of the highly organized man, and he did not care for the consequences in your mind, if you were so stupid as not to take him aright.

“The physician thinks he is the master, forgetting that God is the Master.”
Source: The Gospel of Sri Ramakrishna (1942), p. 105
Context: God laughs on two occasions. He laughs when the physician says to the patient's mother, "Don't be afraid, mother; I shall certainly cure your boy." God laughs, saying to Himself, "I am going to take his life, and this man says he will save it!" The physician thinks he is the master, forgetting that God is the Master. God laughs again when two brothers divide their land with a string, saying to each other, "This side is mine and that side is yours." He laughs and says to Himself, "The whole universe belongs to Me, but they say they own this portion or that portion."

“The arts put man at the center of the universe, whether he belongs there or not.”
Bennington College address (1970)
Context: The arts put man at the center of the universe, whether he belongs there or not. Military science, on the other hand, treats man as garbage — and his children, and his cities, too. Military science is probably right about the contemptibility of man in the vastness of the universe. Still — I deny that contemptibility, and I beg you to deny it, through the creation of appreciation of art.

Source: How to Read a Book: The Classic Guide to Intelligent Reading