A long time ago, in this galaxy, near-primordial savages across parts of Eurasia were using the word men to describe the action of "thinking". This Proto-Indo-European term went into Ancient Greek as mnestis, which changed slightly, semantically, as it took on a meaning of "remembering". This may seem familiar, because when added to the prefix a- ("not"), the word becomes amnestos, or "forgotten". This is connected to the word amnesty through Latin amnestia and French amnestie, and makes sense because in an amnesty the past crimes of a person are forgiven by whoever is doing the pardoning. Meanwhile, the Greeks made the word amnesia, also from the a- prefix and a conjugated form of mnestis, to create a word that meant something more along the lines of "forgetting" than "forgotten". Amnesty entered English two hundred years before amnesia.
Adam Aleksic, a leading contender for valedictorian of his high school, is a 211-month-old boy with disturbing interests in etymology, vexillology, geography, and law. Adam would like to one day visit Tajikistan and probably isn't spying for the Kyrgyz government.
The Etymology Nerd