Thomas Nagel on reason
Reason, if there is such a thing, can serve as a court of appeal not only against the received opinions and habits of our community but also against the peculiarities of our personal perspective. It is something each individual can find within himself, but at the same time it has universal authority. Reason provides, mysteriously, a way of distancing oneself from common opinion and received practices that is not a mere elevation of individuality—not a determination to express one’s idiosyncratic self rather than go along with everyone else. Whoever appeals to reason purports to discover a source of authority within himself that is not merely personal, or societal, but universal—and that should also persuade others who are willing to listen to it.
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The essential characteristic of reasoning is its generality. If I have reasons to conclude or to believe or to want or to do something, they cannot be reasons just for me—they would have to justify anyone else doing the same in my place.
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How is it possible that creatures like ourselves, supplied with the contingent capacities of a biological species whose very existence appears to be radically accidental, should have access to universally valid methods of objective thought?
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Descartes reveals that there are some thoughts which we cannot get outside of. […] To get outside of ourselves at all, in the way that permits some judgments to be reclassified as mere appearances, there must be others that we think straight. […] And once the existence of a single thought that we cannot get outside of is recognized, it becomes clear that the number and variety of such thoughts may be considerable.
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What kind of self-understanding would make our capacity to think comprehensible?
I believe there is no informative general answer to this question, because the authority of the most fundamental kinds of thought reveals itself only from inside each of them and cannot be underwritten by a theory of the thinker. The primacy of self-understanding is precisely what has to be resisted.
The Last Word, Chapters 1 & 2
quote thomas nagel rationality metaphilosophy