Wednesday, April 17, 2013

How to Disprove a Scientific Theory

Photo of chipmunk back turned towards camera.
As I've slogged through Simmons' book, "What Darwin Didn't Know" (2004), I've pointed out, ad nauseam, that he doesn't seem to know how to refute/disprove/falsify a scientific theory. I thought I'd spend some time discussing how one can go about doing that, as well as what doesn't work.

It has occurred to me that I may be accidentally depicting the Theory of Evolution as unfalsifiable, because for each objection Simmons brings up, I seem have a rationalization.

I hope to clear the air on that, as there are effective ways at disproving theories, and there are ineffective ways. The problems with Simmons' arguments, that I've been pointing out, is that his approach is always ineffective - for instance, by pointing at something we don't know yet, as though that "casts doubt" on the theory, or invalidates the facts we do have.

So, let's discuss.

How to Falsify a Scientific Theory

Theories, if we were to reduce them to basic components, have two parts:
  • The model
  • The data/facts
The data/facts is everything we've investigated, all the studies, all the samples and examples. For evolution, this would be the mapping of genomes, the discovery and cataloging of fossils, the studies and direct observation/testing of evolution on a smaller scale.

Graphic of a theory 'shrink-wrapped' around the facts
The model is the conceptual explanation for all the available data, best-fit to accurately account for the preponderance of evidence, and contradicts as little data as possible. Ironically, in the common language, "theory" means "an unproven idea", whereas in science, it's the pinnacle conclusion - almost the exact opposite. It's like the container that's shrink-wrapped around all the "data" objects. 

Falsifying the Model

The model is essentially the mechanisms explained - how the phenomenon works. The Theory of Gravity, for example, is our current understanding of how this force operates in nature.

To falsify the model is to attempt to find something wrong with how it works, and demonstrate that it cannot work that way. For instance, one could take Newtonian mechanics, and demonstrate that they can't work while approaching the speed of light. In this sense, Newton's three laws are technically falsified - but we still use them, as they're still useful within the original context for which they were investigated (macroscopic at low speeds).

Importantly, we should note that it's wise to choose a "fundamental" mechanism of the theory to attack. If we're interested in disabling Bob's car (because we hate that guy), it's far more effective to pull the spark plugs, as opposed to swiping the rear-view mirror. Losing the mirror is nothing more than a minor inconvenience.

Likewise, addressing a tangential aspect of evolutionary theory may not be as effective as falsifying a core mechanism. For instance, Darwin himself commented that evolutionary theory hinges on the existence of some kind of hereditary mechanism.

The power of Selection, whether exercised by man or brought into play under nature through the struggle for existence and the consequent survival of the fittest, absolutely depends on the variability of organic beings. Without variability, nothing can be effected; slight individual differences, however, suffice for the work, and are probably the chief or sole means in the production of new species. (source)
We ended up discovering DNA, which solved this particular problem. If it turned out that neither DNA, nor any other hereditary mechanism existed, evolutionary theory would be in ruins.

Anti-evolution antagonists (or would that be "anti-evolution proponents"?)  have attempted this. Probably the closest they've gotten to succeeding so far, is a concept known as Irreducible Complexity - which sought to demonstrate that many complex structures couldn't have been generated by evolution. Unfortunately for them, this concept is not much more than a smoldering crater at this point (which can be discussed separately as a digression).

To summarize - identify a core mechanism to the theory that everything else depends upon, and find a way to demonstrate that it can't work - not necessarily that it hasn't, but that it can't. That's a question of history, particularly in the next approach to falsifying a theory.

Falsifying the Data/Facts

What good is a theory if there's no facts for it to describe? Since the theory arises from all the data gathered, this is frequently another approach to falsifying it.

A theory like evolution is considered valid because it's overwhelmingly met its burden of proof, and is significantly positively demonstrated. If all the supporting evidence were systematically refuted, there'd be no more legs under that table. If we found out that DNA is a hoax, that all the fossils were artificially built, that all the direct observations were fabricated, the theory of evolution would be in big trouble.

That's where most of the "controversy" exists in the evolution debate. For instance, the anti-evolution crowd insists there's no direct observation of speciation, or that the fossils are put there by the devil to trick us - or 2.3 plethoras of other assertions.

That's fine, and maybe they'll be successful knocking out those table legs.  The main difficulty is that the vast majority of the supporting data must be refuted - not just a few. The majority of the table legs have to be knocked out before the table will fall.

... otherwise, what will happen is that the rebuttals will be processed, investigations will begin, and the model will be adjusted to fit the new set of facts - and we'll have a newer, better theory.

What about Simmons?

That's not what Simmons accomplishes. Let's look at how he approaches falsifying evolution.

Refuting the Theory

He does make frequent stabs at the mechanisms of evolution, but all of his arguments I've encountered so far (in all of the 38 pages I've gotten through at this point), have basically come down to severe misconceptions and ignorance about basic evolutionary theory, combined with severe argumentative errors.

Straw Men

Pointing out that Bob's car does not have helicopter rotors is not a refutation that it's a car. Likewise, pointing out that some species haven't' evolved appreciably in millions of years is not a refutation of evolution, since evolution occurs relative to how poorly suited a lineage is to its environment... which can be fast, or slow.

He specializes in many Straw Man arguments.

Arguments from Ignorance

Actually, I'm not sure if this particular fallacy fits - but it's close. Many of his arguments, so far, have been pointing at something we don't know, with the implication being that there's something wrong with evolutionary theory.

For instance, he'll point out that we're missing a fossil record for a particular species' lineage, or that the evolutionary path for breastfeeding is unknown.

Everything we know about evolution right now was unknown at some point. That's not a problem. If we were first mapping out the geographical region of Florida, and there were sections where the map was blank because we hadn't figured it out yet, that would do nothing towards refuting the portions of the map we did explore.

The arguments of this type are probably the most worthless he could conjure.

It's true that Evolution has a burden of proof, but it's also important to point out that there's many levels of demonstration, from broad/meta support, to demonstration of very specific examples. We can demonstrate that "macro evolution" occurs without knowing the exact evolutionary path of every species that has ever existed.

... I get the feeling that Simmons is sometimes trying to make this case that if we don't know everything about evolution, we don't know anything (which is false).


I'm not sure how else to label this type of argument. It's kind of like a Straw Man, but combined with obfuscation.

Let's say that we're asserting that Bob has a car that he drives. Simmons' approach to refuting this would be to say:
We reviewed the security camera records, and discovered that he has never been to Walmart with his car, therefore he does not own or drive a car.
It should be obvious what's wrong with this argument - there are other possibilities as to where Bob would have driven. It boils down to insisting that the idea Bob owns a car necessarily means he would have driven to Walmart at some point.

No, there are other possibilities. This does nothing to weaken the case that Bob does own and drive a car.

Obvious? Sure - but how about this?
Human beings have gone from walking on all fours to bipedal locomotion, lost most of their fur (hair), silenced ovulation (eggs are released without a female going into "heat"), gained millions of sweat glands, developed breasts (when not lactating), nearly doubled in height, lengthened their arms or shortened their legs, and learned to communicate in extremely complex ways. Yet there are many animal and plant species in our environment that have not changed appreciably during the same period.
- Page 27-28 / Emphasis mine

It's not so obvious here what the problem is, is it?

Like Simmons analogously assuming that Bob would necessarily have driven to Walmart, he's assuming here that Evolution says all creatures necessarily evolve at the same rate, continuously, without ever having periods of stagnation - as opposed to evolving at a rate that's inversely proportional to how well suited the current form is its current environment. If one doesn't realize that, this may seem like a salient objection.

His misconceptions about many contexts completely derail his ability to mount an effective rebuttal.

All - and I'm not exaggerating - all his arguments have boiled down to combinations of these types of errors, with a convoluted mixture of logical fallacies thrown in for good measure.

He's "attempting" to refute both the model and the data of evolution, and ends up flailing around clumsily like trying to fight a swarm of bees with a wiffle bat.

He doesn't have a clue what he's doing - which isn't surprising since he doesn't even appear to know what a scientific theory is.

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