Saturday, May 21, 2016

How To Think Rationally About Claims


I've recently encountered many people who are otherwise very intelligent, but who, for one reason or another, came to believe very foolish things, like libertarian free will, or that we have a soul. It's not that they're stupid or anything, it's mostly due to them just lacking information or having the wrong information in the subject matter, and/or are suffering from poor reasoning skills.

Knowing how to think critically is absolutely essential to being a rational person. We hear numerous claims everyday. But how do we make sense of them? How do we evaluate whether there is any truth to them or not? Well, the answer is long, and I'm in no position to give a full assessment of all the relevant factors. But I can outline a few very important things everyone should know when evaluating the validity of a claim.

Let's start with the claim that the soul exists. By 'soul' I don't mean anything in the metaphoric sense. I'm talking about the traditional notion of a soul, the kind that Descartes believed in: the invisible ghost that resides in our bodies, that animates us, and gives our intellect. This is a belief mostly left over from religion, but is still believed by a surprising number of educated people today. One way to evaluate a claim like this is to ask yourself, if it were true, what would have to be the case? In other words, if souls were real, what would have to be the case logically and scientifically? Let's explore this.

If souls were real, it would have to be the case that the immaterial substance that made up the soul—whatever it is—had to be able to overcome the natural forces in and between the atoms that make up your body. That means there would have to be extra forces at work that apply to the atoms in your body that do not apply to the atoms that make up inanimate matter, like rocks. This echos a view once popular among philosophers and biologists until the end of the 19th century known as vitalism. On vitalism there is something fundamentally different about living things and non-living things. Living things have a life energy that non-living things don't. This would have to be the case—at least for humans—if souls exist.

But the relentless progress of science has shown that this is not the case. There are no special forces or energies that exist in living things that non-living things do not have. There is no life energy out there, despite what all the Deepak Chopras of the world insist. Vitalism has been utterly discredited as an accurate description of reality. All the particles that make up you and I and rocks and trees are made up of the same three things — protons, neutrons, and electrons, that's it. And all the forces that govern them are the electromagnetic force, and the strong and the weak nuclear forces. Gravity is the forth force but is really not a force, it's the curvature of spacetime. Those are the fundamental components that make up everything in your everyday experience and there is no room for anything else. This information has just not gotten out there into the popular understanding of science, but in time it will. The bottom line is this — we fully understand the particles and forces that make up you and I and rocks and trees and planets and there is no room for anything else that can have a causal impact on the atoms that make up your body, like a soul. That is one idea that science has falsified, and we know this through the proper way of reasoning about claims by philosophizing on what would have to be the case if the claim were true.

And so you might naturally ask, "What about dark matter? We don't know understand what it is yet, so why couldn't whatever the soul is be like dark matter?" This is a good question. The answer is that if you understand the nature of dark matter, whatever dark matter is it doesn't interact with the atoms that make up our body and so it cannot have a causal effect on them. If dark matter did interact with our bodies we would have found it by now through our particle accelerators and have incorporated it into the laws of physics. We've been able to find all the particles and forces that are strong enough to interact with our atoms, and that's how we know you're only made up of atoms governed by the forces in the Standard Model and gravity. That's it. So if the soul was like dark matter, it would be too weakly interacting to have any affect on the atoms in your body, but since this soul is supposed to be responsible for animating you, that logically cannot be the case.

Still yet, after I explain this all to educated people, many insist we have a soul. "Science doesn't know everything," they say. And I agree with them. But science doesn't have to know everything in order to know something. We don't have to literally know everything about a particular subject in order to rule out certain claims about it. I can't explain consciousness, but I know it isn't caused by leprechaun farts. Science is mainly in the business of falsifying ideas. The dualistic soul was one idea that science has falsified. Whatever consciousness is, it isn't due to a dualistic soul. That's one conclusion you can arrive at by knowing how to reason properly coupled with a sufficient amount of subject matter knowledge.

So the takeaway here is fairly simple. One of the proper ways to reason about a particular claim is to ask yourself what would have to be the case—what would have to be true, if the claim were true. And to evaluate that, you don't necessarily have to have all of the knowledge of a particular field. You just have to know enough about what's relevant to what would have to be true if the claim is true. Once you can determine what would have to be true if the claim were true, then you're in a better position to narrow down your research into the validity of the claim. As in my example, if the dualistic soul existed, forces would have to exist that only apply to you (or things with souls) and not to other matter that doesn't have a soul. Since those extra forces are nowhere to be found and we can fully describe a person with the available forces we know of, the dualistic soul is false. On top of that, such an idea would violate fundamental laws like the law of the conservation of energy. So through this kind of reasoning, we can be sure that the dualistic notion of the soul is false.

If more people employed this kind of reasoning when evaluating claims, especially their own beliefs, then more people wouldn't believe so many absurd claims, like that we have a soul. The same line of reasoning can be employed to evaluate free will, psychic "phenomena" like telekinesis, young earth creationism, and a host of other claims. It's not necessarily what you know, it's how you arrived at it that really matters.

Now, of course there are more ways to rationally evaluate claims. One is to use a Bayesian approach whereby you take two competing hypothesis and then evaluate what would be the probability of a given piece of evidence if either of those hypotheses were true. In other words, assume hypothesis H1 is true, and then ask what would be the probability or likelihood of finding evidence E, and then change it to assume if hypothesis H2 were true, what would be the probability or likelihood of finding evidence E? But that's for another post.

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