NEW YORK (TheStreet) -- With the stock market achieving new highs on several days in May, the question isn't if there will be a correction, but when.
While calling market tops is notoriously hard, perhaps we can look to the great philosophers for wisdom on how the markets might behave.
There's certainly been a huge run up in the market since the 2008 crash -- the S&P 500 has tripled since its February 2009 low -- and the fact is some real earnings growth is being recorded by many companies currently. S&P 500 average price-to-earnings ratio is only at about 17 right now, which is not out of line with historic norms.
The interesting philosophical question is why we have so little idea when turning points in the market may come. Much of it is linked to deep psychological insights which economists are only beginning to understand. As the 19th century German philosopher Arthur Schopenhauer explained, we have two experiences in life -- our experience of the external world (the things we observe), but then also all our inner experiences (thoughts, feelings, emotions, pains). The latter, which are a major part of our lives, are utterly hidden from anybody else. In response, the famous 20th century philosopher Ludwig Wittgenstein wrote in his Remarks on the Philosophy of Psychology, Vol II, "It is then as if I realized the inner is always hidden." This has huge economic implications: If all our inner lives are so hidden, how on earth can we make predictions about human behavioral patterns and ones that are going to affect the market?