Cogito, Ergo, Sum

"One evening, sitting beside a wood stove, Descartes evolved the maxim Cogito, ergo, sum: 'I think, therefore I am.' This, he believed, was self-evident. The one thing of which we could be certain was our mind's experience of doubt. But this revealed the limitation of the human mind, and the very notion of 'limitation' would make no sense if we did not have a prior conception of 'perfection.' A perfection that did not exist, however, would be a contradiction in terms. Ergo, the Ultimate Perfection - God - must be a reality. This so-called proof is unlikely to satisfy a modern unbeliever, and it shows the impotence of pure reason when faced with such issues. Rational thought is indispensable for our effective functioning in the world. It is at its best when directed toward a pragmatic goal or when, like Descartes, we withdraw from the mundane to consider something as objectively as possible. But when we ask why the world exists (if it does!) or whether life has meaning, reason can make little headway, and the object of our thought itself can become strange to us. Descartes beside his stove, in his cold, empty world, locked into his own uncertainty, and uttering a 'proof' which is little more than a mental conundrum, embodies the spiritual dilemma of modern humanity." - Karen Armstrong, The Battle for God, p. 71-72