“You will only be remembered for two things: the problems you solve, or the ones you create.”

Variant: We can not solve our problems with the same level of thinking that created them

Stopped in Our Tracks, Book Two: Excerpts from U.G.'s Dialogues (2005) by K. Chandrasekhar

Letter to A.S. Suvorin (October 27, 1888)
Letters

Flash Crowd, section 7, in Three Trips in Time and Space (1973), edited by Robert Silverberg, p. 65

Source: 1980s, That Benediction is Where You Are (1985), p. 18
Context: From childhood we are trained to have problems. When we are sent to school, we have to learn how to write, how to read, and all the rest of it. How to write becomes a problem to the child. Please follow this carefully. Mathematics becomes a problem, history becomes a problem, as does chemistry. So the child is educated, from childhood, to live with problems — the problem of God, problem of a dozen things. So our brains are conditioned, trained, educated to live with problems. From childhood we have done this. What happens when a brain is educated in problems? It can never solve problems; it can only create more problems. When a brain that is trained to have problems, and to live with problems, solves one problem, in the very solution of that problem, it creates more problems. From childhood we are trained, educated to live with problems and, therefore, being centred in problems, we can never solve any problem completely. It is only the free brain that is not conditioned to problems that can solve problems. It is one of our constant burdens to have problems all the time. Therefore our brains are never quiet, free to observe, to look. So we are asking: Is it possible not to have a single problem but to face problems? But to understand those problems, and to totally resolve them, the brain must be free.

as quoted by Sandhya Ramesh in: [Interview: 'There's No Conflict Between Lack of Evidence of String Theory and Work Being Done on It', The Wire, Bengaluru, 7 January 2018, https://thewire.in/science/theres-no-conflict-lack-evidence-string-theory-work-done]

K-Linesː A Theory of Memory (1980)
Context: When you "get an idea," or "solve a problem," or have a "memorable experience," you create what we shall call a K-line. This K-line gets connected to those "mental agencies" that were actively involved in the memorable event. When that K-line is later "activated," it reactivates some of those mental agencies, creating a "partial mental state" resembling the original.

Objective Knowledge: An Evolutionary Approach (1972)