People don’t come preassembled, but are glued together by life

Laurence Gonzales in Deep Survival discusses adaptation. Page 59.

In that and other ways, the immune system continuously rearranges the organism’s relationship to its environment. That’s called adaptation. A lifetime of experience builds the system, but a subtle change in the environment can mean that the system no longer has the correct response.

[snip]

The emotions are another mechanism for defining self (actually creating the self) during the process of protecting what is within from what is without, both by avoiding or fighting what is bad and by seeking out what is good. As Joseph LeDoux put it, “People don’t come preassembled, but are glued together by life.” Like the immune system, the emotional system evolves continuously, taking experiences and situations and attaching emotional value to them in subtle gradations of risk and reward.