It's not true about the 21 grams. That was an error in measurement back in 1907 when Duncan McDougall claimed to have weighed a soul. There's no weight loss with death, which is fine with most people because we've long assumed the soul was a weightless, sizeless, timeless substance anyway.
Still, weightless, size-less, timeless substances are scientific dead ends. If there's no way to detect a thing, then there's no way for science to get a grip on it. That's fine with most fans of the soul. Science should keep its hands off souls. But it's not OK with scientists. The dead end forces them to look for another explanation for why living bodies act so differently from dead ones.
They have a new explanation, but it's not a thing. It is, in fact weightless and sizeless, but not timeless or a substance. I don't mean to be mysterious. I'm talking science so let me be concrete.
Picture a small pile of metal. A machinist shapes it up and voila you've got, let's say, a lock and key. It's great. It's got function. It serves your purposes. Much more so than a small pile of metal. So what did you add that made it functional?
Oxford professor Michael Polanyi says nothing was added. What makes it functional is not an addition but a subtraction. A pile of metal can take all sorts of forms. You can pile it this way; you can pile it that way. Locks and keys are highly constrained. Machinists make the parts with what they call "low tolerances" meaning a lot of constraint and specificity on their shapes and sizes so that the parts interact with each other just so.
As a result, the lock and key do fewer things, not more than the pile did. When the lock and key get old and worn out, they lose function, but, Polanyi points out, they do so by gaining more possibilities, more configurations of the parts or technically, more "degrees of freedom." In other words the parts get looser than they were. Now the old clunker can jam or the key flops around.
A broken machine does more things, not less. We prefer our machines highly constrained. An unreliable computer has more behaviors, more states it can be in. A reliable one has less, only the behaviors we want. The weightless, sizeless non-substance that makes things functional is constraint. You can't talk about the weight of the states the lock and key can't be in. You can't talk about the size of the states they can't be in. The states they can't be in aren't some added substance. But you can talk about time because constraint is a difference that occurs over time: Before, a loose pile of metal; after, a constrained lock and key, after, again a loose lock and key.
I used to have an unreliable computer. I'm not saying whose operating system it ran, but I'll tell you it was way too versatile for me. I was amazed by the sheer variety of ways it would act. It seemed to invent new creative ways of bombing every day. For example, at the drop of a hat it would do blue screens which I'll grant was clever but not what I wanted when writing under a deadline. I wanted it to behave itself, to show some self-constraint. One day I got out of my blue-lighted chair and dropped down to the competitor's store. I had heard that their computers were less versatile. They did fewer things like blue screening. That was fine with me. I didn't need versatility; I needed functional constraint. I bought one and it's been a good three years for me and my much more limited computer.
As a result, I've become more constrained too. I love my replacement computer by which I mean to say I'm constrained by it. I'd even say loyal, addicted and domesticated to it. Before, if you asked me what kind of computer I wanted, I'd have been more flexible. Now, I'm less flexible. I want only the kind I have. It is, what in business we call a proprietary good, one you shop for by brand. You accept no substitutes. In other words, you're constrained by it.
My computer's makers likes it that way. They wants me to be as loyal, addicted and domesticated as I am. And now that the likes of me are buying their products, their employees go to work and rather than working on just anything all day, they're highly constrained too. They're constrained to working on how to make things that are constrained the way people like me want them to be. That way we customers will become that much more loyal, addicted and domesticated to their products. In other words more constrained.
And then also if a friend asks me what kind of computer to buy, I won't say "Oh, I don't know," or name any of a dozen other brands. I'll be constrained to saying this brand. And in that way the constraint spreads or propagates.
And what has this got to do with souls? Constraint and constraint propagation apply all the way up and down, with differences along the way that mark the shift from physics to chemistry, to biology to psychology sociology.
At the bottom, if you read my article about Broken Symmetry, you'll find constraint even there. Remember, as the balanced broomstick tips over, the more it tips the more it tips? Before it tips, it is balanced symmetrically. It could tip in any direction. After it tips, its tip-able direction is highly and increasingly constrained.
Your body is not a machine made by a man or, I'll argue, a creator. At least for scientists to fulfill their (constrained) obligation, they can't settle for saying the soul is a weightless, size-less, time-less substance that is made by a bigger fancier weightless, size-less, time-less substance. We can't therefore treat a living soulful being as the equivalent of lock and key made by the machinist. Still, in its functionality, your body and even your mind are like the lock and key if only in that they do consist of parts that are highly constrained to and by each other, and to their context. As the great philosopher Emannuel Kant said, "The definition of an organic body is that it is a body, every part of which is there for the sake of the other (reciprocally as end, and at the same time, means)”
In later articles I'll talk more about how Kant's "means and ends" business relates to constraint, constraint propagation, causality, the origin of life, and souls, and also to missing the sweet souls that come and go in our lives.
In the mean time, if this article constrains your thinking even a little, let it be by encouraging you to tip less toward explaining all behaviors as caused by new things and more toward explanations based on constraint. The leading researcher in this area, Terrence Deacon says, the whole is not more than the sum of its parts, its less. In other words, when parts start interacting with each other as wholes, they constrain each other. The whole lock does less things than the pile of metal pieces can do.
And I know I know, this material is likely to give a reader a headache. That's the way it is with novel constraints sometimes, like the ones imposed by new counter-intuitive ideas. I'll do my best to keep these reflections grounded. And after all, it might be worth the effort. Researchers like Deacon are coming at old mysteries from new angles that might finally split them open, explaining lots.