No offense to Rene Descartes, but this is a much better mantra for surviving in today's world and actually having some hope of a decent retirement. No one is a bigger fan of abstract thought than I am, but Aristotle may have been right in his quest for practical wisdom over mere abstractions.
Now if it only said "I invest, therefore I am." rather than "I trade, therefore I am." it would be just about right. Or didn't you know that trading and investing are not the same thing? My goal is to get rich in the long term, buying securities and holding them for many years at a time. On this time frame, minor fluctuations in the stock market such as the drop a couple weeks ago are meaningless other than a chance to buy your favorite investments on the cheap. Day trading is a chance to lose one's shirt (hopefully not the spiffy one above), and in this I am simply not interested.