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Sunday 27 September 2015


Depending on your point of view, being called a skeptic is either an insult or a compliment. Being called objective is considerably better, but calling yourself objective is sometimes a sign that you're an authoritarian jerk who thinks they know all the answers. One of the problems is that "skeptical" is sometimes used to mean quite different things. Today I want to discuss the various meanings people use when they say "skeptical" and what those different kinds of skepticism are good for.

Skepticism, Belief, Disbelief, And Inquiry

In everyday use, "skeptical" often means, "I think this idea is probably not true". It does not merely imply that you aren't convinced that something is true, rather that you actively believe that something else is true instead (even if you don't know what that something else is).

This difference is a little bit subtle, but it's extremely important. An example should help. If you are totally unaware of something - let's say you've never heard of the concept of the narwhal before - you have no reason to doubt that it exists. You have no reason to believe that it does exist either. You exist in a state of true, pure neutrality, blissfully unaware of those weird ocean-going mammals.

True happiness can only be achieved when you forget about narwhals. Not many people know that.
Then someone comes along and tells you about this weird blubbery thing with a long horn that swims about in the Arctic Ocean. At that point, there are essentially three things that can happen :
  1. You remain truly neutral. You have no other evidence other than someone's say-so, so you don't form an opinion one way or the other*. For you, the question, "why would a whale have a horn ?" is as valid as, "why would a whale not have a horn ?".
  2. You can believe that it doesn't exist, with an arbitrary degree of intensity. Come on, a whale with a horn ? That's as ridiculous as Donald Trump's hair !
  3.  You believe that it does exist, with an arbitrary degree of intensity. A whale with a horn would be able to skewer its luckless enemies, so why not ?
* You might also just not give a damn about some stupid horny fish thing, which has the same end result.

Of course the third viewpoint isn't skeptical at all (well, we'll get back to that), while the second one is pure skepticism (unless you are "certain" that narwhals don't exist). It would also be legitimate to label the first as a sort of skepticism, but clearly it's different from the way the term is most often used in everyday life.

Being skeptical in either of those two senses is essential for rational, scientific enquiry. Without doubt, one cannot learn. Of course, although a degree of skepticism is necessary for rational inquiry, being skeptical doesn't guarantee you're being rational. It's perfectly possible to be skeptical for completely irrational reasons.

In science there are - unfortunately - some words which are used with quite different meanings than in everyday parlance. "Theory" is the best known of these : more commonly understood as "just an idea or model", in scientific usage it specifically refers to a model which has been very well-tested and not yet disproven. It is much more than "just an idea", which in science is referred to as a hypothesis.

Next time you want to say, "it's only a theory", replace it with "it's only a very well-tested model" and see if that still works. Anyone want to make an extension for Chrome that can do that automatically ?

Source. I would slightly disagree with "bias", which can mean a deliberate distortion of the facts - but it isn't always done with a deliberate, sinister motive. Bias can also happen quite accidentally if you forget to look at the whole system, or don't realise that what you're studying is affected by more factors than those which you have direct control over.
But there's no accepted special scientific definition for "skeptical". Just as in everyday life, we use "skeptical" both when we're actively seeking evidence to show that something is not true. but also if we're trying to prove if something is true or not (i.e. without any preference as to which conclusion we want to find). What we really mean by the latter is that we're trying to be purely rational and objective. I think it's useful to differentiate quite explicitly between those two approaches - both have their uses, as we shall see.

With the narwhal, there are several ways you could behave when presented with evidence of the creature, depending on if you initially went for option 1, 2, or 3 and how intensely you cling to your belief (why you react in that particular way is another subject entirely - you may well have no choice in the matter at all). Your skepticism (or lack of) makes a difference to how you respond to evidence.

A photo, you could say, could have been photoshopped so it doesn't constitute useful evidence, so you remain neutral. Or you could say that because it obviously has been photoshopped (because your own belief that they don't exist is so strong that there's no other explanation) that means narwhals clearly don't, or even can't, exist (an example of extreme, self-reinforcing bias that makes it essentially impossible to change your mind). Or that the photograph is damned good evidence that narwhals did exist once, but not necessarily that they still do. All of these are varieties of skepticism or denial.

Of course, you could also believe that the photograph is sufficient evidence to believe in narwhals (though you might stop short of calling it "proof"). Even though that is not a skeptical position, it's clearly rational. It does depend on the exact quality of the photograph though.

Sometimes photographic "proof" isn't all it's cracked up to be. There is actually a whale in this shot, if you look closely. Not a narwhal, unfortunately.
Scientists and non-scientists alike are fully capable of responding in any of these ways. Each have their own virtues and flaws, and it isn't always easy to judge which one is best. It really depends strongly on the details of the evidence at hand.

The Middle Ground And The Importance Of Good Vocabulary

One might think that surely the true neutral position is always the best one if the evidence is inconclusive or lacking entirely. This is how I personally feel towards agnosticism, which is what the above short example is based on. But that's my judgement call, and other people have very different opinions depending on how they assess the evidence. The point is that evidence can usually be interpreted in different ways, and it isn't always possible to be truly objective, no matter how much we might want to be.

Which makes it damn hard to get away with saying "I'm being rational and objective", instead of skeptical, because someone will almost always disagree with you and claim that their position is more rational and objective than yours. All you can do is say, "I'm trying to be objective", which is rather less satisfying than saying, "I'm being skeptical" but infinitely more accurate than claiming you've actually reached an indisputable truth, most of the time.

Without the word, "try", you are basically pronouncing your judgement as infallible and superior to everyone else's, which is almost never the case. Saying that you are "trying to be objective" admits your flaws while making it clear that you don't have a preference for whatever conclusion you end up with. Which is very different from the conventional meaning of "skeptical", which is to seek to disprove something (i.e. debunking) - though if you state this is what you're doing, at least everyone knows where they stand and everyone accepts there is room for doubt.

In an ideal world, the true neutral position probably is the best one. But in reality, it's rare that people can remain truly neutral on all issues : we are not machines. In the case of the narwhal, where we were seeking only to establish its existence, one may argue that remaining neutral is actually the wrong approach. You can go out and catch a narwhal to prove it exists, but it's almost impossible to prove that it doesn't exist without draining the oceans. Safer, then, to believe it doesn't exist until proof is presented that it does.

From National Geographic. Some people would even be prepared to question having the body of a narwhal as proof of their existence, as was done with the platypus. Establishing proof does happen, it's just rare and damn difficult.
This belief that it doesn't exist should not constitute an absolute dismissal of any prospect that it might exist. It's supposed to be a much more moderate position than denying any evidence on the prejudice that they can't exist (a point of view which, however, it is very, very important to remember most certainly does occur). While "skeptical" is not a perfect word, it is at least distinct from "denial", which is an altogether stronger position. It is, however, also quite different from the true neutral position*, which doesn't really have its own separate word.

* In this case that would state that actively believing that narwhals don't exist, however moderate that belief might be, is misguided.

Generally speaking, it's this modest level of negativity which is what we mean by skepticism in science. But not always. Suppose you establish with certainty the existence of narwhals, say by taking a sonar scan. So you stop "believing" in them because now you know they exist, but you still don't know very much about them.

But if you now go on trying to prove some more specific fact about narwhals, like whether they are grey or brown, it makes little or no sense to actively believe one way or the other. You may as well remain truly neutral until presented with good evidence, because you know you can eventually get it (and in this case it makes little or no practical difference). That's where having a word that means, "I am trying to perform a rigorous, objective analysis to establish the facts and I genuinely don't care what the result will be" would be useful. "Skeptical" has negative connotations, "verify" has positive ones, but there doesn't seem to be an adequate neutral word for an analysis with an explicit lack of an opinion.

When Skepticism Is Better Than Trying To Be Objective

So why does science generally prefer to be modestly skeptical rather than truly neutral ? Well, if you try and disprove something but fail, then it's stood up to a stronger attack than if you weren't trying to disprove it. That makes it more likely to be true, and you're less likely to spin the results in its favour. This requires you to be moderate though, because if you're a denier you can twist any fact - any fact, no matter how obvious the implication would be to a truly neutral observer - to make it mean whatever you want it to mean. You might not like the end result of your investigations, but you have to be willing to change your mind.

But science is built not so much on skepticism as it is on skepticism's socially awkward cousin : doubt. Whether you believe a theory or not is not as important as the ability to change your opinion. It doesn't really matter if you're trying to disprove or prove a theory by testing it, provided you accept the measurements you get and the consequences of those numbers for your theory. So in that sense, trying to prove a theory could be seen as just as "skeptical" as trying to disprove one. Again, I'm not sure the English language is entirely adequate here.

The problem is that it's frickin' hard to prove most theories. You can't really prove something without disproving all other possible explanations. All you can do, in practise, is show that one idea makes predictions which are consistent with observations. On the other hand, it's usually a lot easier to disprove individual theories - a single failed prediction (in an ideal world) will do just that. And so the scientific method favours the skeptical approach as a matter of simple pragmatism. That certainly doesn't mean that individual scientists don't think that some theories are really true though, not by a long shot.

Normally I avoid quoting Einstein because one can never trust quotes from the internet about Einstein, but in this case it really doesn't matter who said it.
While some people mistake theories for simple, unproven models, others have the opposite problem and confuse them with facts. This is just as bad. Being skeptical, or doubtful, of measured facts and figures is stupid (as long as the experiments were performed correctly). Being doubtful of theories - the models that tie a lot of disparate facts together - is the very essence of the scientific method, and if you don't doubt, you don't science. Yeah, English problems again.

(It's probably worth mentioning here that practically everyone is a denier on a least a few issues. I suspect it's impossible to function if you don't have some convictions, even if those convictions aren't fully justified. "Keep an open mind, but not so open your brains fall out..." - if you doubt everything, you learn nothing)

Peer review is an excellent example of the importance of all this in real life. In science you don't just get to publish your findings without at least one other (usually anonymous) expert checking them over. The process is mediated by the journal editor, who keeps an eye on the referees to make sure they're not being overly-harsh or supportive. Ideally, you don't want someone who's truly neutral toward your research : you want someone who's skeptical, but of course not a denier.

Peer review certainly doesn't guarantee objectivity. Nothing does. But, if it's being done correctly, it does make things more objective than not doing it at all. Problems arise if your reviewer is too far from this ideal position of skepticism : if they're a denier (as happened to me once), they can seriously delay* or even prevent your research from getting published; if they're neutral it's less of a problem but they may not question things rigorously enough; if they're too supportive they may actually overlook fundamental errors in your analysis.

* This really matters. Working to correct errors on a paper is a full-time activity. A bad referee could choose to question your every argument in excruciating detail to the point of absurdity, forcing you to spend months that you could have spent on other research instead.

It's a very careful balancing act to get this all right. Keeping reviewers anonymous helps, since they may feel under less pressure to be unduly hostile towards non-mainstream research. But humans are fickle, capricious, and fallible, and it is inevitable that mistakes get made no matter how careful a system of checks and balances is used. Exposing those mistakes is essential, but let's not go all "oh woe is me, science has failed !" because human beings behave like, well, human beings.

I've never seen this happen at a conference, though it's come close on occasion.


There are different meanings of skeptical, from "trying to disprove something" to essentially "trying to establish something". Both sorts of behaviour are appropriate in the right context, and it's unfortunate that we don't have a real word for the second type.

The essence of all rational enquiry, not just science, is not really skepticism but doubt. Actively trying to prove yourself wrong is just one part of that. Trying to prove yourself right is also valid - indeed you should test what your theory gets right as well as wrong - but it's both safer and easier to go for the skeptical, disproving approach.

Being a skeptic is not the same as being a denier. The skeptical position is one that's willing (if sometimes highly reluctant) to change given evidence; a denier wouldn't change their position if a narwhal stabbed them in the buttocks. Of course, the boundary between the two is fuzzy : a really extreme skeptic might require evidence so strong as to be unobtainable. Sometimes it's extremely hard to tell the difference between the two; in my opinion, deniers are often the ones shouting most loudly that they're skeptics.

Doing good science is a very careful juggling act on a tightrope that's also on fire. Being human, you're fallible and subjective. You may not want to be, but you are, so deal with it. The only thing you can hope to be truly objective about are the raw numerical measurements - any theory you create to explain them will inevitably have some subjective bias. But... there's good news !  Because you can make objective measurements, you can objectively test your theory.

There's some bad news as well though. You might be able to falsify your theory, but you'll probably never be able to prove that it's correct. Some doubts will almost certainly remain. But you know what ? That's actually a good thing. It means you've placed one more stone on the road of progress. Your theory was better than what came before, and allows others to go a little further. Maybe one day we'll reach the end of the road and have some sort of final uber-theory that can crush its enemies beneath its mighty feet. Maybe we'll never have complete understanding - but each advancement offers new opportunities and new challenges. Only one thing is certain : if we don't try, we don't learn. The road to the stars is paved with doubt.


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