based on the nature of the threat (signal anxiety). However—and this too is taken from Darwin—under certain conditions the excess excitation can become disorganizing and nonadaptive.

The second Darwin is the Darwin of The Origin of Species (1859). This is the influence that is most often noted. It is used to support Freud's views when he postulates a correspondence between phylogenesis (humanity's evolution since its origins) and ontogenesis (the individual development of the child of today). Freud refers to Ernest Haeckel's hypothesis according to which ontogenesis repeats phylogenesis. Freud writes, "Important biological analogies have enabled us to acknowledge that individual psychic evolution repeats, in abbreviated form, the evolution of humanity" (1910c). In "From the History of an Infantile Neurosis" (1918b), he writes, "The phylogenetic schemas that the child possesseson which they were based and the impossibility of accepting Haeckel's hypothesis.

It is worth noting that in these texts (especially in the "Overview") Freud is more Lamarckian than Darwinian: it is essential to his theory that individual traits be transmissible by incorporation into the genetic heritage. Freud never abandoned this postulate in spite of the discredit that befell Lamarck's ideas.

The third and final Darwin is the Darwin of The Descent of Man (1871), a work that postulated a process of continuous evolution from animal to man and distinguished stages within human evolution, that is, a temporal sequence that was also a form of progress, a hierarchy ranging from the most primitive forms to the most noble: lower animals, higher animals, the "savage," civilized man. Darwin distinguished between "inferior"