Occam’s Razor and Closed-Mindedness
An SGU listener by the name of Jenny recently sent me the following question:
When we skeptics are faced with an unexplained occurrence, we work up a list of possible explanations based on our knowledge of how the world works and then use Occam’s Razor to prune out the most unlikely ones.
We often preemptively wield the razor by leaving off the list supernatural explanations that have been tried and debunked dozens of times. This is a tempting time-saving measure, but it’s also a violation of our proclaimed skeptic’s creed of being open to ANY explanation that is supported by evidence.
I often wonder how Richard Saunders manages to stick to the creed with such good humor–I don’t have the patience, myself.This misuse of Occam’s Razor is, in a way, the reciprocal of the argument from ignorance–the argument from presumed knowledge, let’s say. For we skeptics to state categorically that a supernatural explanation CANNOT be true is just as much a logical fallacy as for a credulous person to state that our naturalistic explanations cannot explain the phenomenon in question. It also leaves us open to accusations of arrogance and closed-mindedness, which in this case actually have some basis.
This is a great question. While Jenny is a skeptic who is just trying to understand skeptical philosophy, similar arguments are often used by the proponents of various supernatural explanations, and so a detailed answer is helpful on multiple fronts.
Being Open
It is certainly a virtue to be open-minded, but trouble arises in how we define “open-minded”. It is often used by true-believers as an equivalent of faith, meaning that any odd belief must be accepted regardless of the logic and evidence against it. Whereas being open-minded in the scientific sense means treating all propositions fairly, without ideological bias. And then letting the empirical chips fall where they may – allowing science to function as a meritocracy of ideas.
In other words, we do not a-prior reject ideas, but once the evidence is in it is acceptable to reject failed notions in science.
Jenny is taking this principle but then making an unstated assumption that leads her astray. She is assuming that if we did not “preemptively wield the razor” by leaving off our initial list of possible hypotheses supernatural explanations, that the resulting list would be finite. Rather, if no filter or criteria were used in forming an initial list of hypothesis, the resulting list would be unending, limited only by our time and imagination.
One might then argue that only supernatural explanations which are already believed by some would need to go on the list, but this is just applying another criterion – popularity. It that not being closed-minded to ideas that are not popular? It is not the fault of an idea that no one has yet been clever enough to think of it.
We must apply some criteria in forming our list of possible explanations. Once this is recognized, we can then consider the appropriateness of popularity as a criterion. History has shown it is not a very good criterion.
What scientists generally do (and certainly within the applied science of medicine we take great pains to do) is to form a list of hypotheses from most likely to least likely. We then test the most likely explanations first (although sometimes we also go after the low-hanging fruit by testing the easiest to test hypotheses first, even if they are not the most likely).
But “least likely” trails off into infinity without objective end. So the real question is, how far down the list of prior probability are we going to go? That is a judgment call, but one that scientists have to make.
In practice what scientists often do is start testing hypotheses, starting with the most likely and most testable, until they find a hypothesis that is confirmed by evidence. But then they must also confirm this hypothesis by showing that alternative explanations are not true. But how many alternative explanations must be show to be untrue? As I argued above, the answer cannot be “all of them” because there is no limit to the number of alternate hypotheses unless we use some criteria of prior probability. In practice the answer is “all reasonable alternatives” with “reasonable” being a judgment call.
This is not only fair, it is necessary, otherwise science would grind to a halt testing an unlimited list of alternate hypotheses to each theory.
Further, it does not exclude even the most unlikely explanation from science. If such an alternate hypothesis turned out to be true, then the “more likely” hypotheses should all fail. Once scientists have exhaustively excluded their list of reasonable hypotheses, they will go back to the drawing board to see where they went wrong or too extend their list of hypotheses further down to previously considered “unlikely” alternatives.
Eventually they will get to the right answer, and they will already have done the necessary work of excluding more likely hypotheses.
Supernatural Hypotheses
The second problem with Jenny’s position is the claim that skeptics assume supernatural explanations cannot be true. Depending upon how one defines “supernatural” this statement may be little more than a tautology. But actually Jenny here is confusing philosophical naturalism with methodological naturalism.
The scientific method is dependent upon methodological naturalism – meaning that we cannot invoke the equivalent of “magic” as an explanation. This is because all ideas in science must be testable – there must be a way to falsify any scientific hypothesis with evidence. A supernatural hypothesis by definition cannot be tested because it is not contained within the laws of nature.
Therefore supernatural notions are not scientific hypotheses because they cannot be tested, and they therefore do not belong on a list of alternate hypotheses. These are the rules of science – if you don’t play by these rules, you are not doing science.
But “supernatural” does not merely mean currently unknown. Science explores news laws and new types of explanations all the time. Again, once we exhaust our list of possible explanations based upon current knowledge, we then need to seek new knowledge. This is often the most difficult, and creative, part of science – coming up with entirely new ideas and then (sometimes even harder) figuring out a way to test these ideas.
But science is actually agnostic toward the question of whether or not there are supernatural forces at work in the universe. Again – definitions get tricky here, because one could argue that any force at work in the universe is by definition natural. But let’s say that a supernatural notion would include the claim that there is an undetectable agency at work in the universe that could arbitrarily suspend the laws of nature. Such a claim is untestable. At best science could detect enduring anomalies – observations that forever defy scientific explanation. But science could never confirm that a supernatural explanation were correct.
From a practical point of view we keep coming back to the primary criterion of a scientific hypothesis – it must be testable and falsifiable. If it is, then it can go on the list of possible hypotheses. If it isn’t, then it is not scientific and it does not go on the list. The “natural vs supernatural” distinction is ultimately meaningless except for this feature. This is methodological naturalism, and science requires it to work. For any ideas outside of methodological naturalism, science does not hold that they are false, just unknowable to science.
Conclusion
Finally, it must be recognized that science builds upon itself. With each new question or idea we are not starting from scratch, as if we have no prior knowledge. It is not only practical, it is necessary, to approach questions in light of what has already been well-established. Only when that approach fails should we consider alternate explanations – but any testable hypothesis is ultimately fair game.
Excellent explanation. I wish I had read this a week ago, before I had a long discussion with a relative in which I used this principle, but couldn’t adequately defend why it was appropriate.
Excellent post, Steve. Have you considered writing/publishing your own primer on skeptical tools, along the lines of Demon Haunted World, only shorter? The posts I’ve seen you do over the years, combined with the podcasts, add up to a good basic understanding of the skeptical toolkit. We can always use another easy-access book on those lines, because I’ve seen people utterly misunderstand the classic arguments (the Action Skeptics blog has a good anecdote on someone interpreting Sagan’s Dragon in the exact opposite manner it was intended). We need all the weapons we can get *cough*Skeptologistspickedup*cough*.
Ranson,
Yes – I do plan to do just that. Although, ironically, I am too busy writing to do any writing. Meaning, my weekly schedule of content (along with that medical career thingy) makes it difficult for me to do longer term projects like books, but I really need to get that done. What I really need is an editor willing to do some of the busy work for me.
This is a great post. I would also add that Occam’s Razor need not only apply to supernatural explanations (as some people tend to think). It is a tool for evaluating the probable veracity of one hypothesis over another, all things being equal. For example, Ptolemy’s geocentric model of the universe fit the known data as well as a geocentric model. Ptolemy’s model was simply more complicated, positing the existence of phenomena that the geocentric model did not require. The geocentric model was, therefore, simply more probable than the alternative.
Steven,
Pish and tosh, Doctor. The fact that you’re writing for seventeen different blogs and shows (as well as doing medicine, having a family, etc.) is no reason not to do more. We already know you’re a geek, so we know that sleep is optional. You wouldn’t give up this easily if it were a D&D campaign, would you?
My tongue is drilling a hole in my cheek, by the way. I’ll gladly take what I can get, when I can get it.
…
Sooner is better, though.
“What scientists generally do (and certainly within the applied science of medicine we take great pains to do) is to form a list of hypotheses from most likely to least likely.”
-Dr. Novella
That’s more like Hickam’s dictum than Occam’s razor. Occam’s razor favors finding a single cause of all the symptoms, even if it’s less likely than multiple causes.
The standard closed-mindedness test is, “What evidence would change your mind?” And is anyone looking for that evidence?
A theory can be so flexible that it’s practically unfalsifiable.
It took an accidental discovery of a giant amoeba and its tracks to change scientists’ minds about the Cambrian explosion. But did the discovery have to be accidental? Didn’t anyone hypothesize that the tracks could be left by something other than multicellular animals? Looks like yet another black swan.
Max – I disagree about Occam’s razor. It does not favor a single diagnosis, but introducing the fewest new elements in order to explain a patient’s presentation. Sure, don’t give them two rare diseases when one will do. But, three common diseases is often more likely than one rare disease. Further, one disease often leads to another, or share common risk factors. And, as we get older we tend to accumulate multiple chronic diseases.
In short, you are misreading Occam’s razor. It does not favor the simplest explanation, but the one with the fewest new assumptions.
Steven,
Thanks for this and all the other “fundamentals of skepticism” info you’ve put out there.
It does make me cringe a little when I see grammar goofs in science blog posts, I can’t help it. Like: “…which are already believed by some would need to go on the this, but this is…” (under your Being Open header, paragraph 4.) Not that I want to be a grammar cop and call out everyone’s mistakes. I certainly make them, too. But I wonder if it hurts the point of the post?
On your future book, I’ve done quite a bit of editing, though mostly in music and much less in text. If I have the skill to help I’d be happy to do it. I also have a friend who is an English teacher and might be looking for something to do over her summer break.
Max– how did the giant ameoba change minds about the Cambrian explosion? As far as I can tell, it only altered an interpretation of evidence for pre-explosion bilaterian metazoans (i.e. the ‘long fuse’ hypothesis for bilaterian evolution).
I think Jenny has demonstrated the tendency, common in some, to ascribe the unknown to the supernatural. When looking into something, the “goddidit” answer must immediately be rejected simply because not a single god has been demonstrated to exist. People seem to have the impression that “I don’t know” is not a valid answer, but that is an utterly ridiculous position because if you really don’t know, then any statement other than “I don’t know” is entirely unsupported by evidence.
If we look at the history of the astronomer Fred Hoyle, he claimed to not believe in a god until one day he came up with enormous numbers for the energy needed as a condition for the formation of carbon within a star. His thinking suddenly became fuzzy and he started to believe that something out there must have created these conditions which he personally believed to be impossible. Unfortunately he seemed to miss out on the next logical step: how did that magical creature that can achieve the impossible come about?
@LovleAnjel: The giant amoeba obviously used its psychic powers. It is actually the carcass of a Time Lord so its psychic powers were actually employed to alter perception after the discovery of the fossil, long after the time lord had expired in our past but while the time lord was still alive and well at the time of the discovery of the deceased time lord’s remains. Isn’t that all obvious?
LovleAnjel,
Misha Matz, the guy who discovered the giant amoebas, said, “I personally think now that the whole Precambrian may have been exclusively the reign of protists. Our observations open up this possible way of interpreting the Precambrian fossil record.”
You say supernatural claims are untestable but isn’t that what James Randi does with his million dollar challenge, test supernatural claims? Or how about the study that tested the efficacy of intercessory prayer (I believe by the Templeton Foundation)? Didn’t that study conclude through scientific testing that the supernatural claim of prayer didn’t work. If these tests are valid, isn’t it conceivable that they could have a positive result? What am I missing?
Eric – Again, this gets to the definition of “supernatural”. If one could truly use a stick to find water, then whatever force was at work would be part of nature, and therefore not supernatural.
In practice what the examples you raise are testing are not supernatural explanations, but specific claims that can be tested. Randi makes this very clear – a claimant must be able to state what, precisely, they can do in a testable manner. So Randi will test if someone can find water with a stick, but he does not test the underlying explanation. He is asking the question “is there an effect” – not “is the effect supernatural.”
We can also say that claims that qualify for the paranormal challenge must involve effects that are sufficiently outside the realm of existing science that they cannot be explained with conventional means.
But theoretically, if someone got their hands on an advanced piece of alien technology they could win Randi’s challenge without demonstrating the paranormal, simply by using science that is currently unknown.
“You say supernatural claims are untestable but isn’t that what James Randi does with his million dollar challenge, test supernatural claims?”
You can’t test the claims themselves, they are just words, anecdotes. You can test attempts to fulfill the claim. The JREF requires specific explanations of what you claim to be able to do, and then sets up a controlled experiment to see if you can do them. Randi tests the attempts to perform the claim. Further, when a claimant fails to demonstrate the claimed ability, say telepathy for example, it doesn’t mean telepathy has been disproved, nor does the JREF claim it does. It means that particular claimant failed to demonstrate the claimed ability in that particular test. Conceivably, the claimant could succeed in a new test and is free to apply to do so,under JREF rules.
“Or how about the study that tested the efficacy of intercessory prayer (I believe by the Templeton Foundation)? Didn’t that study conclude through scientific testing that the supernatural claim of prayer didn’t work.”
See above. It proved only that intercessory didn’t work that time. It does not disprove intercessory prayer forever, nor does it claim to.
“If these tests are valid, isn’t it conceivable that they could have a positive result?”
Yes, it is conceivable. But one cannot run a constant test covering all attempts of intercessory prayer. They ran the test of intercessory prayer and found no measurable effect.
“What am I missing?”
Scientific tests and experiments build upon one another, hopefully until the sum of results begins to establish a reliable pattern of success or failure. As regards intercessory prayer, all tests showing positive results have been shown lacking in proper control protocols or outright fraud, while all properly controlled tests have found no measurable effect attributable to prayer. This is an emerging pattern that suggests intercessory prayer is illusory, not a real effect. No doubt further tests will be done, and if similar results are found the doubts about intercessory prayer become increasingly justified. It is possible that test results will reverse themselves, that properly controlled tests reveal positive results at a significant level. If so, science will go nuts on relciation attempts, contrary to paranormalists’ belief that science runs from controversy or results that upset the science applecart.
Dammit, this Novella guy is like an omnipresent android, everywhere all at once. Beat me to the punch.
“Misha Matz, the guy who discovered the giant amoebas, said, “I personally think now that the whole Precambrian may have been exclusively the reign of protists. Our observations open up this possible way of interpreting the Precambrian fossil record.””
Matz is not a paleontologist– as a person who works on ichnofossils, the very thing his discovery affected, I can tell you that only changed possible interpretations for tracks and trails. We do have body fossils from the Precambrian (the Ediacaran fauna), and they are assuredly not protists. No one would argue that the world then was (and still is) dominated by single-celled organisms. We had simply never had an instance of them leaving macro-ichnofossils (as opposed to micro-ichnofossils, which we knew they do) before this.
Since there is no time period called the precambrian, you have to consider the first 4 billion years of the Earth’s life as precambrian, in which case it is not new or a changing of minds to consider it to be dominated by protists and bacteria. One of the liveliest areas of thought in paleo is when bilaterians appeared and why, and that deals with genetics and molecular biology more than the fossil record.
This was not a fossil rabbit.
I think someone was inflating the importance of that discovery, for whatever reason. I can tell you, we didn’t stand and shout “Bulls***” and demand that his view be suppressed– we were all VERY excited that something so cool turned up.
And yes, I think a Time Lord is the simplest explanation. I must now go check my DVD collection for easter eggs.
Steven – Thanks for your quick reply. I’ve skimmed over the JREF website where it defines the challenge as such:
—At JREF, we offer a one-million-dollar prize to anyone who can show, under proper observing conditions, evidence of any paranormal, supernatural, or occult power or event.
Protocols
2.2 What is the definition of “paranormal” in regards to the Challenge?
Webster’s Online Dictionary defines “paranormal” as “not scientifically explainable; supernatural.”
Within the Challenge, this means that at the time your application is submitted and approved, your claim will be considered paranormal for the duration. If, after testing, it is decided that your ability is either scientifically explainable or will be someday, you needn’t worry. If the JREF has agreed to test you, then your claim is paranormal.—
JREF are establishing as a condition of winning the challenge that a testable claim can be shown to be evidence of the paranormal or suprenatural based on current scientific understanding. In fairness they discount new evidence but seem to be open to the concept that new evidence may never reverse the result.
Eric – yes but my point is they define paranormal as not currently explainable by science. They even acknowledge this is a moving target.
This is unresolvable because “supernatural” is a meaningless term. I know what the Randi Challenge says – the point of the challenge is to test the claims of those who profess paranormal abilities. It is a mechanism, primarily, to expose con artists.
But the Randi challenge does not actually test the existence of the paranormal, but rather the specific claims of individuals.
Remember, Randi does not believe the paranormal exists. He is simply accepting the premise of claimaints for the purpose of conducting a test of specific claims. He himself is not equating currently unexplained with paranormal, but is simply using it as a way of limiting the test to claims he feels are very unlikely and are the types of claims commonly used by charlatans and con artists.
To get back to my primary point – the concept of supernatural is ultimately meaningless. The only thing that matters is what can be tested.
Steven – I know Randi doesn’t believe in the paranormal, I don’t either. I only want to contend your assertion that supernatural notions are untestable. To you and me, claims of the supernatural are meaningless, but I think that those who make the claims are the ones that define specifically what they are. Once someone makes a claim to the supernatural, then that becomes the working definition which may or may not be subject to testing. If the claim is subject to testing by JREF’s standards, and a scientific explanation is found, then the supernatural claim is negative (and vice versa, conceptually). This accords with the Webster’s Dictionary definition listed on the JREF site. That’s all I’m trying to say. This issue of language is like getting on a merry-go-round, we go and go but don’t get anywhere.
Besides, is it really fair or open minded for the JREF to say right up front that paranormal claims are untestable by definition? “Yeah, we’ll give you a million dollars if you can prove something we have already defined as being unprovable.”
Eric
I really don’t think it should be declared that refusing to honor “supernatural” explanations is an EXPLICIT rule of science. Rather, it is implicit in the fact that “supernatural” is poorly defined. What do the proponents of the “supernatural” mean when they use this term?
The most common definitions of supernatural usually include that a supernatural entity is not bound by laws of nature, it exhibits some kind of agency or teleology, and/or is empirically undetectable. All of these definitions can be a priori shown to be incoherent or problematic. (I won’t do that here, to keep this post short.)
In response to Ms. Jenny, I wouldn’t say it’s closed-minded to rule out the supernatural, I’d say it’s perfectly rational to recognize as a non-starter the use of a poorly-defined concept as an explanation for anything.
“Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.” – Sherlock Holmes
Everyone should check out this video on “open mindedness”. This was brought to our attention by David Gorski on SBM blog.
http://www.youtube.com/watch?v=T69TOuqaqXI&eurl=http%3A%2F%2Fwww%2Egoogle%2Ecom%2Freader%2Fview%2F%3Fhl%3Den%26tab%3Dwy&feature=player_embedded
“Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.” – Sherlock Holmes
Load of hogwash unless Holmes can: (1) explain how a person might reliably “eliminate the impossible”, which seems to require omniscience, and (2) explain why he is certain that eliminating all the impossiblities will lead to only one remaining choice.
What if eliminating all the impossiblities leaves 47 possibilities? All they all therefore the truth?
How old is Holmes anyway? Shouldn’t he be long dead by now?