“He transforms all concepts into incommunicable, solidified objects. To refute him is to become contaminated with unreality.”

Source: The Mind and the Brain, 1907, p. 76

The close of his Nobel lecture: "The Statistical Interpretations of Quantum Mechanics" (11 December 1954) http://nobelprize.org/nobel_prizes/physics/laureates/1954/born-lecture.html
Context: Can we call something with which the concepts of position and motion cannot be associated in the usual way, a thing, or a particle? And if not, what is the reality which our theory has been invented to describe?
The answer to this is no longer physics, but philosophy. … Here I will only say that I am emphatically in favour of the retention of the particle idea. Naturally, it is necessary to redefine what is meant. For this, well-developed concepts are available which appear in mathematics under the name of invariants in transformations. Every object that we perceive appears in innumerable aspects. The concept of the object is the invariant of all these aspects. From this point of view, the present universally used system of concepts in which particles and waves appear simultaneously, can be completely justified. The latest research on nuclei and elementary particles has led us, however, to limits beyond which this system of concepts itself does not appear to suffice. The lesson to be learned from what I have told of the origin of quantum mechanics is that probable refinements of mathematical methods will not suffice to produce a satisfactory theory, but that somewhere in our doctrine is hidden a concept, unjustified by experience, which we must eliminate to open up the road.

page 90.
Manual of Political Economy

Source: The Courage to Be (1952), p. 124
Context: There are realms of reality or — more exactly — of abstraction from reality in which the most complete detachment is the adequate cognitive approach. Everything which can be expressed in terms of quantitative measurement has this character. But it is most inadequate to apply the same approach to reality in its infinite concreteness. A self which has become a matter of calculation and management has ceased to be a self. It has become a thing. You must participate in a self in order to know what it is. But by participating you change it. In all existential knowledge both subject and object are transformed by the very act of knowing.

Source: Sayings of Sri Ramakrishna (1960), p. 840

Source: 1910s, Introduction to Mathematical Philosophy (1919), Ch. 16: Descriptions

Source: I Am Legend (1954), Ch. 16
Context: All these years, he thought, dreaming about a companion. Now I meet one and the first thing I do is distrust her, treat her crudely and impatiently.
And yet there was really nothing else he could do. He had accepted too long the proposition that he was the only normal person left. It didn’t matter that she looked normal. He’d seen too many of them lying in their coma that looked as healthy as she. They weren’t, though, and he knew it. The simple fact that she had been walking in the sunlight wasn’t enough to tip the scales on the side of trusting acceptance. He had doubted too long. His concept of the society had become ironbound. It was almost impossible for him to believe that there were others like him. And, after the first shock had diminished, all the dogma of his long years alone had asserted itself.

"Honoring Dr. DuBois", speech at International Cultural Evening at Carnegie Hall, 23 February 1968, published in Freedomways: A Quarterly Review of the Negro Freedom Movement, compiled in Esther Cooper Jackson (ed.), Freedomways Reader: Prophets In Their Own Country, p. 36 https://books.google.com/books?id=-oivNmSJOfAC&pg=PA36&dq=%22the+supreme+task+is+to+organize+and+unite%22
1960s

A Short History of Decay (1949)