To Leibniz

[Do you ever find yourself thinking about how you would explain modern science to someone from the past? It happens to me every so often.  Here is how I might explain about life to Leibniz.]

Dr. Leibniz, I found your idea about animals being machines made of smaller machines in an infinite series fascinating, but this is something we actually understand very well here in the future, and it turns out to work somewhat differently than that.

You have seen animalcules through Leeuwenhoek's microscope? We call these "single-celled animals." Large animals, such as humans, are made up of billions of these animals. Like a self-sufficient colony on an island, an animal contains cells of many types, each with their specific jobs-- there are skin cells which are tough and flat, there are brain cells that connect to many neighbors to allow communication, there are red blood cells that carry oxygen from the lungs to various parts of the body, and white blood cells that act as defenders against infection. Sometimes these cells are organized into tissues which are organized into organs. While these cells are in a way complete organisms, in practice they have such special needs that none of them can naturally live on their own outside the body.

Like all cells, egg cells contain smaller machines within them that perform various functions. We call these organelles. Right, from the French. Some of these organelles themselves seem to be very similar to whole cells, so your idea is basically right even down to this level. But here we approaching the limit of how small something can be and still consist of matter. The components of these organelles are molecules. Molecules are alchemical compounds of what are called, for historical reasons, atoms, though they are actually divisible. Their parts explain their various alchemical properties. And those parts (called electrons, protons, and neutrons. Yes, like electricity, which is very important, but we will get into that later.) are divisible into smaller parts called quarks. (By the time quarks were discovered, Latin and Greek were no longer the international language of science. English, actually. Some time around 1950, I think? Yes, it was German for a while, but then you lost a couple of big wars.) And the quarks seems to be divisible into smaller parts called strings (because their behavior seems to have something to do with the laws of harmony, like vibrating strings) and those may in fact be made up of the fundamental particles of space, what you might call monads. But this is getting at the limits of what is known. Yes, it does seem like the pattern is for smaller and smaller structure, but there are good reasons for believing that this is actually a fundamental scale. I don't really understand how it is derived, but the formula involves the finite speed of light and the strength of gravitation.

Anyway, if you imagine being shrunk down to the scale of a molecule, you can stand inside the workings of a cell, like a vast mill, built out of atoms as a house is built of bricks. Looking into the largest of these organelles, we find incredibly long molecules, all coiled up. Imagine these molecules as a kind of bead necklace. Yes, I know I'm mixing metaphors here. The individual beads are small components, made of perhaps a dozen atoms. There are only four types of beads, and they do not follow a repeating pattern. Yes, exactly, you see it! An alphabet of four letters, containing all the instructions needed to build an entire animal. 

These beads are of a special form. Like magnets, they attract similar beads floating through the cell. But they are shaped so that only a complementary bead can attach. So now imagine the necklace as two necklaces joined together next to each other, with each bead attached to its complement. A tiny machine splits the necklace into two strands. Each strand waves around in the water, pulling beads toward it, but the beads can only attach if they are the correct bead. So after a time, each half of the necklace has become a copy of the original necklace. Sure, it seems slow, but events move faster the smaller you get. Yes, like a clock pendulum.

Reproduction among cells (animalcules) works like this. A mechanical process copies the instructions, so that the cell carries two copies. Other machines read off these instructions, and use them to build the other organelles. No, I wouldn't say they are intelligent, exactly. It is more like the punched cards of a jacquard loom. Imagine a loom that wove cloth, but also could somehow produce copies of its own cards. If one could make looms out of cloth, that would be all that is needed. That is how reproduction happens. So there doesn't need to be an infinite number of smaller copies inside, do you see? Only machines with instructions that are capable of building machines and giving them a copy of the instructions.

Well, it is unbelievably intricate, and beyond what human-made machines are able to do even in my time. And there are some people who believe that. But others think that this process, too, could have occurred naturally. At one point, billions of years in the past, the only living things on earth were animalcules. The ones that happened to work well together were more successful at obtaining food and reproducing, and ones that worked together better still formed even more complex colonies, until their empires conquered the globe. And each empire of animalcules was succeeded by one even stronger and better able to work together, until the societies became like simple worms. And the worms that happened to have little fins were better at swimming, and the ones with tougher skins were better at not being eaten, and so had more children until the world was full of tough, finned worms. And so it went-- worms into fishes and millipedes, and fishes into amphibians, and amphibians into reptiles, and reptiles into mammals and birds, and humans as a particularly successful mammal. We can find fossils formed from the preserved bones of these creatures in exactly that sequence, stacked layer on top of layer in the rock. Yes, it took billions of years.

There are no fossils of animalcules as far as I know, but we can speculate that before that the ocean was a kind of vast soup full of organelles, and before that simply full of molecules that could make copies of themselves, or at least, could make more likely other molecules which facilitated the formation of the first kind of molecules.

Well, yes, it does seem very unlikely to come about on its own. But the universe is, as far as we can tell, infinite in extent. Each star contains its own system of worlds. So it only had to happen once in the infinite universe. We look around and say, this world seems fit for us, but if the scientists are right, it was a matter of both us and the environment gradually changing to become more and more fit for each other. So it may or may not be the best of all possible worlds, but it is at least one of the few worlds that is good enough to have led to us.

Certainly, God may have set up the process on our world, like a farmer planting and tending seeds.  But God must have arisen somehow. We understand that more intelligent animals have more complex brains. We understand, basically, how the complex machine that is the brain calculates ideas based on other ideas. So God, being more intelligent than man, must be more complex than man. He cannot be fundamental, but must have arisen through at least as complex a process. So this account, even if it weren't true of our world, must have been true of some world, somewhere. It does what science ought to do-- it explains how more complicated things come about based on simpler things. 

No, I haven't talked about the soul, yet. A lot of the things that people in your time attributed to the soul-- life, memory, rationality-- we can explain mechanically. But the sensation of conscious existence is still a mystery. It may be, as you thought, a fundamental property of all the simplest parts of the world. It is a very hard thing to study. We may someday be able to build a machine that acts in every way like a person. But whether or not that machine has its own experiencer, how could we ever tell? It may be, like any automaton, simply an extremely convincing simulacrum.