How small can animals get? Researchers have been studying the fairy wasp, one of the smallest animals on Earth, and found that the wasps have made some sacrifices in order to be so small. The cells that make up their brains and nervous systems are missing some parts (to be specific, they’re missing nuclei).
So shrinking people, like in Honey, I Shrunk the Kids, might not be a good idea. It’s certainly possible to discard parts of your brain cells and remain alive—the fairy wasp proves that—but would you still be the same person?
Fantastic Voyage by Isaac Asimov solved this problem by explaining that shrunken people are actually made of tiny, shrunken atoms. Regularly sized atoms are full of empty space, and since they’re government by quantum mechanics they’re prone to weird behavior anyway, so this weird atom shrinking idea makes some sense.
Obviously the wasps are doing fine with their minimalist brain cells, and once again this proves just how flexible life can be. You can even make wasps smaller than single celled organisms.