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.
                                    
“In order really to write one has to sink deep into the self and become lost there.”
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John Banville 97
Irish writer 1945Related quotes
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On the cultural sacrifices made by African Americans in higher classes in “Playwright August Wilson on Writing About Black America” https://billmoyers.com/story/august-wilson-on-writing-about-black-america/ (Bill Moyers, 1988)
“To write is to read one's own self”
Sketchbook 1946-1949
                                        
                                        Fiction, The Call of Cthulhu (1926) 
Source: The Complete Works of H.P. Lovecraft