It brought forth the qualities of not only intelligence, but imagination and ingenuity as well. The internal environment caused the evolutionary changes that led to man. Concepts, thoughts, and imaginings are the product of that organ. Ideas lead to new, unpredictable experiences. Salk believes that ideas possess a characteristic as tangible as material substances.
Ideas evolve just as do living things.
In their way ideas are a kind of evolutionary feedback system, cycling from the evolutionary process and in turn prompting further, higher evolutionary jumps. This perhaps led to new fields such as the cognitive and neuro- sciences. Salk declares that these are primary for survival. For Salk, change is the order of the day. The natural selective pressure will now favor one who not only accepts change but welcomes it and contributes to it.