the.com/inversion

means The act of flipping something to face the opposite direction — upside down, inside out, or in reverse order — and in thinking, approaching a question from its opposite end rather than head-on.

from From Latin invertere, 'to turn upside down or inside out' — in- ('into') plus vertere ('to turn'). Vertere is the same root that gives us 'verse,' 'version,' and 'vertigo' — all words about turning. The problem-solving sense (argue from the opposite case) is old, favored by thinkers like Carl Jacobi, who had a motto in Latin roughly translating to 'invert, always invert' as a way to crack hard problems by working from the undesired outcome backward.