Both ignorance and the old metaphysics tend to produce these undesirable nervous effects of reversed order and so non-survival evaluation. If we use the nervous ystem in a way which is against its survival structure, we must expect non-survival. Human history is short, but already we have astonishing records of extinction.

The map is not the territory.

...no thought, if it be non-mathematical in spirit, can be trusted, and, although mathematicians sometimes make mistakes, the spirit of mathematics is always right and always sound.

Indeed neither life nor science bothers about "essences"-they leave "essences" to metaphysics, which is neither life nor science.