In the course of learning, first from the environment of our childhood and later from whomever or whatever we come in contact with.
At this point, many examples of mental cages come to mind:
a. a water resourses expert and civil engineer who dismisses climate change becuse the data is bad
b. An MIT professor of engineering, who, in a light snow tells me: “look, it’s snowing, what’s this about climate change?”
c. The Boeing Executive who dresses down an engineer who has been part of the old culture concerned with process and safety now must stick to “The Plan.” A direct result is the 737 Max.
d. The former dean of the Harvard Business School whose only objective was to maximize the earnings of his students.
e. The conservative addiction to ideology: low taxes and small government with no criteria for its effect on the lives of anyone but the rich
f. The Supreme Court that is blind to modern technology or is a pawn of conservatives and we get Citizens United
g. The NRA. No need for explanation.
Humanity has yet to realize what being human should be, or to define specificly and publically discuss, announce, debate what is meaningful about life.
a. Context: how we got here; we are mired in either not being interested, or taking a tribal position, an arbitrary set of beliefs that the group is attached to, the worst being (in the US of A) conservative positions with no knowledge of anything, the extreme, extreme example being our chief executioner (sorry executive).