Darwin’s principle of natural selection. The idea is that in any population of self-reproducing organisms, there will be variations in the genetic material and upbringing that different individuals have.
A Brief History of Time
Stephen Hawking
Remember what has been emphasized earlier: Our brain and nervous system cannot tell the difference between a real experience, and one that is vividly imagined. Our automatic Creative Mechanism always acts and reacts appropriately to the environment, circumstance, or situation. The only information concerning the environment, circumstance, or situation available to it is what you believe to be true concerning it.
Psycho-Cybernetics
Maxwell Maltz
I consider it a dangerous misconception of mental hygiene to assume that what man needs in the first place is equilibrium or, as it is called in biology, “homeostasis,” i.e., a tensionless state. What man actually needs is not a tensionless state but rather the striving and struggling for a worthwhile goal, a freely chosen task.
Man's Search for Meaning
Viktor E. Frankl
You shouldn’t have been born. Your existence is as close to impossible as can be. To dismiss the impossible is to dismiss yourself.
The Humans
Matt Haig
The Goldilocks Rule states that humans experience peak motivation when working on tasks that are right on the edge of their current abilities. Not too hard. Not too easy. Just right.
Atomic Habits
James Clear