One of the strange parts of our world is how many different types of knowledge swirl about us at any given moment. On your computer screen, a marvel of engineering brought about by, among other things, our understanding of quantum physics, you can read about how quantum physics isn’t real. You feel letters on a keyboard, you see glowing pixels on a screen, you understand (vaguely) how those pixels are made to glow, and then someone on your screen tells you that the whole setup is impossible.

How do we put together these disparate pieces of knowledge? A large part of it is intuitive, which is why you are able to put together your various sensory experiences of your computer into an object you interact with. Kant was the first to recognize this. But there’s also this top layer: you probably vaguely understand how quantum physics makes your computer possible. You see on the screen someone telling you, convincingly, that quantum physics is ridiculous. You personally don’t know enough about quantum physics to argue with the guy on the computer screen. But, most of us would still disagree with him, regardless of our knowledge.

The reason we would disagree with this guy ultimately boils down to authority. Unlike our philosophers, we can’t trace the deductive or inductive arguments of quantum physics back to its source. Even if we did read the papers and the arguments, the mathematics of them are difficult enough to be impossible for an ordinary person. We have to rely on others to tell us what the arguments are and how they work. Our strongest piece of physical evidence for quantum physics is the fact that the computer does work, and that does seem incontrovertible, but the connection to quantum physics again relies on authority. We rely on the New York Times, which presumably relies on the physicists themselves, to tell us what is true or not.

The New York Times gets its authority from the physicists it interviews, who get their authority from the fact that they can make things work. If any piece of that link were broken, like if physicists denounced the New York Times for misrepresenting statements, or if leading computer manufacturers denying the physicists had anything to do with their products, we’d be much harder pressed to defend quantum physics against our convincing arguer.

Another way to think about this is our degree of certainty. For now, I want to focus only on the degree of certainty we have in the physicists themselves, so I won’t examine the New York Times too closely. As I mentioned, these physicists have an advantage, in that their findings can be seen in the real world. They can lend this advantage to their fellow physicists by endorsing them, explicitly or implicitly. Thus, physicists like Stephen Hawking, who work on topics which will never present physical evidence to the layman, like black holes, also tend to be trusted by the layman.

As we get further away from both the physicists and their endorsements, trust breaks down. Or, to be more precise, from the fields in which physicists’ endorsements count, which tends to just be physics. Global warming, for instance, is a theory fairly well supported by inductive and deductive arguments, if you actually look at them. It’s also fairly well supported by scientific authorities. However, after a long and vigorous misinformation campaign, it’s not very well supported by the public, because it lacks physical evidence for the layman. Indeed, the layman doesn’t even know what evidence to look for. If January 20th is a hot day in Boston, that doesn’t prove global warming, and it doesn’t disprove it if it’s a cold day.

I studied Geosciences in university, which means that I understand the arguments themselves for climate change. Most people, however, will not study the arguments, and wouldn’t be able to understand the arguments if they studied them. Their acceptance of global warming, like their acceptance of quantum physics, has to be based on what authorities say. But there are various prominent politicians and businessmen who deny global warming, and these are traditional authorities. So, if the layman is to accept global warming as a fact, as I believe they should, they have to follow the specific authorities that I believe they should.

These specific authorities are scientific authorities, like the National Science Foundation (NSF) and NASA. They’re not “fringe”; they represent the scientific mainstream. But I realize that, even still, they aren’t easy authorities for everyone to follow. I am certain that both the NSF and NASA have believed incorrect things before. I can even name one off the top of my head: NASA claimed that they discovered a lifeform that used arsenic as one of its building blocks (instead of phosphorus), before rapidly backpedaling once they found out their “discovery” was just scientific error.

So, I can’t encourage people to trust in the NSF and NASA based on their infallibility. Instead, I have to encourage people to trust in the NSF and NASA based on their dedication to the scientific method. First, when the NSF and NASA have been wrong, they have admitted they were wrong upon being shown appropriate evidence. This fits in well with Popper’s idea of falsifiability as a key idea in science.

The second reason is that these are both organizations which believe in a truth and strive honestly to achieve it. This is evident in how the organizations are set up, and their accomplishments thus far, especially NASA’s. So, once again, it’s necessary to rely on the physical evidence of science, except this time instead of directly relying on it, we indirectly rely on it as evidence of a general drive towards scientific truth. And striving honestly towards truth, by the way, has to do with everything we’ve talked about so far in this series of essays.

Generally speaking, I believe this is how we should evaluate authorities on matters we don’t know about. In the case of those that speak against global warming, opponents tend not to accept or even understand any evidence that would be contrary to their views. They will not admit that they were wrong, and they do not use others’ work in an attempt to find truth.

And that brings me to the title of this essay. The definitions of hard, soft, and pseudoscience are difficult to get everyone to agree on. For me, however, hard science is distinguished from soft science in how easy it is to disprove it, and how the field tends to react when major theories are disproved. In economics, for instance, it’s very hard to falsify most theories, as deliberately simplified models cannot be disproved by examples from the real world. Furthermore, it’s rare that economic theories actually die, even if the weight of evidence seems firmly against them. Free trade as a method for countries to develop their economy, for instance, is something which does seem to have clear evidence against it, but still has an enormous amount of institutional support.

Soft sciences are distinguished from pseudoscience, though, in their honest pursuit of truth. Economists consider the available evidence and mention it in their papers, even if it’s only to explain why evidence that seems to go against their theory in reality does not. Pseudoscience does not honestly pursue truth. Evidence that goes against pseudoscientific theories is ignored, or, if mentioned, is not explained fairly. Practitioners of alternative medicine, for instance, neither read nor cite the vast traditional medical literature, even though the accomplishments of traditional medicine are evident.

So, when you’re trying to come up with an opinion of some “knowledge” that someone has presented to you, try first to go to their arguments. If you lack the expertise to understand their arguments, go to the authorities, and see who seems to argue in a way that acknowledges the whole story, and is open to be proven wrong. That is the authority you should trust, and that is how you should come up with your opinion on the matter.