Law360, New York (December 16, 2011, 7:09 PM EST) -- One of the first things that a student of statistics learns is that "correlation is not causation." This admonition applies to simple statistics as well as complex models. The classic example is the so-called "sunspot theory of stock prices" — if one were to find that over some period of time stock prices were correlated with sunspot activity, this does not mean that changes in sunspot activity cause changes in stock prices, and one would be ill-advised to base one's investment strategy on such a theory. If it were true that "correlation implies causation," then the logical inverse would be "no correlation implies no causation." The question is: Since the former is false, is also the latter false? That is, when, if ever, is the statement "no correlation does not imply no causation" true?...