“Modern psychology began to flourish at a time when the thermodynamics theory of heat and the theory of potential were finally put on a firm basis and clearly formulated by some of the most eminent scientists of that time. Thus, the idea that energy can neither be created nor destroyed became more or less common knowledge. Any educated person knew this, and it was quite natural to formulate the libido theory on the same lines, that is, to be analogous with the energy theory. Emotional energy could accumulate, be dammed up; and, as it could not be destroyed, either steam had to be let off or sublimation had to take place. The same background prevails today and some excellent authors, who now see quite clearly the fallacy in the libido analogy, inadvertently make the same mistake with other emotional manifestations — such as aggression.
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