Abraham Lincoln was once asked, “How tall should a man be?” “Tall enough that his feet reach the ground,” was his reply.

Building A Shrink Ray? Consult This Grisly Physics Paper About Exploding Horses

Making something giant-sized looks cool in science fiction. Seeing it basically disintegrate under the strain of its own weight wouldn’t look nearly as cool. Okay, maybe it would. But it wouldn’t make for an interesting fight for the protagonist.

The “grisly” paper is On Being the Right Size by J. B. S. Haldane.

An insect, therefore, is not afraid of gravity; it can fall without danger, and can cling to the ceiling with remarkably little trouble. It can go in for elegant and fantastic forms of support like that of the daddy-longlegs. But there is a force which is as formidable to an insect as gravitation to a mammal. This is surface tension. A man coming out of a bath carries with him a film of water of about one-fiftieth of an inch in thickness. This weighs roughly a pound. A wet mouse has to carry about its own weight of water. A wet fly has to lift many times its own weight and, as everyone knows, a fly once wetted by water or any other liquid is in a very serious position indeed. An insect going for a drink is in as great danger as a man leaning out over a precipice in search of food. If it once falls into the grip of the surface tension of the water—that is to say, gets wet—it is likely to remain so until it drowns. A few insects, such as water-beetles, contrive to be unwettable; the majority keep well away from their drink by means of a long proboscis.