It is written that of all the 31 known sentient species, only humans believe in free will. This illusion arises because although perceiving the existence of four dimensions, none the less, their view of time is severely constrained to glimpsed, mostly falsified memories and a probablistic view of the future. Their outlook on life is as if their heads were imprisoned in helmets and vision permitted only through rigid six foot scopes without mirrors or lenses to enhance the passing image while strapped unknowing to flatcars careering under their own momentum along interweaving railroads.
Even if you read the book thirty years ago, i bet you will get the literary reference right away. If you are guessing, I won’t spoil the game but someone I hope will post it below in a comment. It is a classic of twentieth century fiction (actually much based on fact, frighteningly). I re-read it in snatched moments recently. I’ve had little time to draw, hence this rather rough sketch.