“It is said that instinct is innate. But if, on the one hand, we bear in mind that many instincts are acquired, and that, according to a theory hereafter to be explained” (which theory, I frankly confess, I never was able to get hold of), “_all instincts are only hereditary habits_” (italics mine); “if, on the other hand, we observe that intelligence is in some sense held to be innate by all modern schools of philosophy, which agree to reject the theory of the _tabula rasa_” (if there is no _tabula rasa_, there is continued psychological personality, or words have lost their meaning), “and to accept either latent ideas, or _à priori_ forms of thought” (surely only a periphrasis for continued personality and memory) “or pre-ordination of the nervous system and of the organism; _it will be seen that this character of innateness does not constitute an absolute distinction between instinct and intelligence_.
“It is true that intelligence is variable, but so also is instinct, as we have seen. In winter, the Rhine beaver plasters his wall to windward; once he was a builder, now a burrower; once he lived in society, now he is solitary. Intelligence itself can scarcely be more variable . . . instinct may be modified, lost, reawakened.
“Although intelligence is, as a rule, conscious, it may also become unconscious and automatic, without losing its identity. Neither is instinct always so blind, so mechanical, as is supposed, for at times it is at fault. The wasp that has faultily trimmed a leaf of its paper begins again. The bee only gives the hexagonal form to its cell after many attempts and alterations. It is difficult to believe that the loftier instincts” (and surely, then, the more recent instincts) “of the higher animals are not accompanied _by at least a confused consciousness_. There is, therefore, no absolute distinction between instinct and intelligence; there is not a single characteristic which, seriously considered, remains the exclusive property of either. The contrast established between instinctive acts and intellectual acts is, nevertheless, perfectly true, but only when we compare the extremes. _As instinct rises it approaches intelligence—as intelligence descends it approaches instinct_.”