" Kierkegaard was a born goader. He picked quarrels with his contemporaries, broke off personal relationships, and generally made difficulties out of everything. He wrote: ‘Abstraction is disinterested, but for one who exists his existing is the supreme interest.’ He applied the same argumentative attitude to the personnel of philosophical history. He disagreed, for example, with René Descartes, who had founded modern philosophy by stating Cogito ergo sum: I think, therefore I am. For Kierkegaard, Descartes had things back to front. In his own view, human existence comes first: it is the starting point for everything we do, not the result of a logical deduction. My existence is active: I live it and choose it, and this precedes any statement I can make about myself. Moreover, my existence is mine: it is personal. Descartes’ ‘I’ is generic: it could apply to anyone, but Kierkegaard’s ‘I’ is the ‘I’ of an argumentative, anguished misfit. "

― Sarah Bakewell , At the Existentialist Café: Freedom, Being, and Apricot Cocktails