Commentary Just as physicists look for equations to explain the natural world, I have always thought it useful to look for equations to explain human nature. For example, in my book on happiness, I offer this equation: U = I – R. Unhappiness = Image – Reality. The difference between the images we have for our life and the reality of our life is one way of measuring how much unhappiness we experience. Here, I offer another theorem, this time to help explain leftism. A + S = B = L Affluence + Secularism = Boredom = Leftism The search for an equation to help explain leftism (as distinguished from traditional liberalism) emanates from these facts: Most leftists come from the upper and upper-middle class. This was true for the two founders of leftism, Karl Marx and Friedrich Engels. Marx was supported by his family and by Engels, who was …