Jean Jacques Rousseau 
The Social Contract [EPUB ebook] 

For the study of the great writers and thinkers of the past, historical imagination is the first necessity. Without mentally referring to the environment in which they lived, we cannot hope to penetrate below the inessential and temporary to the absolute and permanent value of their thought. Theory, no less than action, is subject to these necessities; the form in which men cast their speculations, no less than the ways in which they behave, are the result of the habits of thought and action which they find around them. Great men make, indeed, individual contributions to the knowledge of their times; but they can never transcend the age in which they live. The questions they try to answer will always be those their contemporaries are asking; their statement of fundamental problems will always be relative to the traditional statements that have been handed down to them. When they are stating what is most startlingly new, they will be most likely to put it in an old fashioned form, and to use the inadequate ideas and formulae of tradition to express the deeper truths towards which they are feeling their way. They will be most the children of their age, when they are rising most above it.