Progress depends on retentiveness

"Those who cannot remember the past are condemned to repeat it."

This quotation, and numerous variations of it, has attained extraordinary ubiquity and immortality in the world of quotations.

But who first said it? And where?

The answer to the first question is George Santayana (1863-1952), the eminent Spanish American thinker.

The answer to the second (in context) is as follows.

Excerpt from: Chapter XII ("Flux and Constancy in Human Nature"), Volume One ("Reason in Common Sense") of The Life of Reason; or, The Phases of Human Progress (five volumes), 1905-1906
Author: George Santayana
Source: Project Gutenberg
Stable URL: http://www.gutenberg.org/files/15000/15000-h/vol1.html

Progress, far from consisting in change, depends on retentiveness. When change is absolute there remains no being to improve and no direction is set for possible improvement: and when experience is not retained, as among savages, infancy is perpetual. Those who cannot remember the past are condemned to repeat it. In the first stage of life the mind is frivolous and easily distracted; it misses progress by failing in consecutiveness and persistence. This is the condition of children and barbarians, in whom instinct has learned nothing from experience. In a second stage men are docile to events, plastic to new habits and suggestions, yet able to graft them on original instincts, which they thus bring to fuller satisfaction. This is the plane of manhood and true progress. Last comes a stage when retentiveness is exhausted and all that happens is at once forgotten; a vain, because unpractical, repetition of the past takes the place of plasticity and fertile readaptation. In a moving world readaptation is the price of longevity. The hard shell, far from protecting the vital principle, condemns it to die down slowly and be gradually chilled; immortality in such a case must have been secured earlier, by giving birth to a generation plastic to the contemporary world and able to retain its lessons. Thus old age is as forgetful as youth, and more incorrigible; it displays the same inattentiveness to conditions; its memory becomes self-repeating and degenerates into an instinctive reaction, like a bird's chirp.

Not all readaptation, however, is progress, for ideal identity must not be lost. The Latin language did not progress when it passed into Italian. It died. Its amiable heirs may console us for its departure, but do not remove the fact that their parent is extinct. So every individual, nation, and religion has its limit of adaptation; so long as the increment it receives is digestible, so long as the organisation already attained is extended and elaborated without being surrendered, growth goes on; but when the foundation itself shifts, when what is gained at the periphery is lost at the centre, the flux appears again and progress is not real. Thus a succession of generations or languages or religions constitutes no progress unless some ideal present at the beginning is transmitted to the end and reaches a better expression there; without this stability at the core no common standard exists and all comparison of value with value must be external and arbitrary. Retentiveness, we must repeat, is the condition of progress.