A theory of poop

Barbacoa, black beans, and corn. Yes, this had been a particularly smelly poop. Not mine, but my daughter’s, who fights every diaper change until she realizes this may actually help her move around more efficiently during her destructive walks about the house. The moment I opened her diaper, my neck snapped in the other direction, my nose instantly repulsed by what it had just whiffed. In that moment, I realized the extent of the simulation. Poop doesn’t have to smell repulsive. And a poopy smell doesn’t have to create a visceral disgust response. No, this was rather programmed in, as a “don’t eat this shit” mechanism.

Your biology teacher, asked about this phenomenon, would just as instinctively remark that random mutations are responsible for the programming of the “poop = don’t eat” response. But let’s try to put ourselves in the shoes of randomness and see if we can figure out how to arrive at this sophisticated level of programming by chance.

As a brief biology refresher, your nose is up there, your butt is a few feet down, and your poop production system is probably somewhere in between. Now presumably in the course of evolution the poop came first, before there came a disgust response from your nose. Evolution said: Let there be poop. And so it became. Presumably at this point poop smelled the way it smelled, but there was no “disgust” wiring present yet, so some poor organism decided to eat its own poop thinking it was an infinite food hack, only for it to get sickly or fall dead. (The alternative would be that poop and its disgust wiring came in the same update, but for a random mutation to achieve that level of collaboration between two very separate systems would surely be out of the question.)

Now, evolution is blind right—straight up stupid. More stupid than the organism that just ate its poop. But these damn organisms are eating poop left and right, getting sick, and dying. And evolution hasn’t the slightest idea! It chugs along and continues to do its thing, guessing one random mutation at a time. It grows an extra mouth here, an extra ligament there, expands a pupil here, extends a neural pathway there, but nothing is coming up advantageous. Organisms just aren’t living long enough to reproduce—the poop is too damn tasty!

Now if you’re evolution and you have to search near infinite problem space in your quest for determining the next mutation to evolve the species you are so gravely responsible for, how long might it take you to iterate through this space before you come up with “Eureka! Make the poop smell bad and elicit a disgust response!”? Well, try to write a script in your favorite programming language that combines words (which in this case would be from an advantageously finite space, unlike evolution’s near infinite space), until the words equal something like “Make the poop smell bad and elicit a disgust response.” This trivial random string generation exercise would probably require billions of years of some for-loop run before you get the result you were aiming for. And note of course that evolution doesn’t have the advantage of “knowing what it’s aiming for.”

Astonishingly, evolution figured this out way faster than that. I can’t be sure when poop=bad found its way into the biome, but let’s be generous and say that it took this blind process a billion years to do so. But a billion years is absolutely nothing compared to infinity. A billion years is extremely impressive for a random process to arrive at a life-saving trait. How is it that evolution, time and time again, seems to search infinite problem spaces randomly way more efficiently than we could ever expect?

Enough with this random mutation nonsense. Wake up and smell the poop.