What is Science?
Science is best viewed as an activity undertaken with a specific goal in mind. That goal is to understand the way nature works. We measure our understanding by the extent to which we can make nature's phenomena predictable and controllable. Any investigative technique that brings us closer to this goal can reasonably be considered part of science.
All of the standard pieces of the scientific method we learned about in high school - experimentation, hypothesis testing, inductive reasoning and so forth - have their role to play in bringing us closer to our goal of predictability and control. By contrast, hypothesizing the actions of ill-defined supernatural entities such as ghosts or poltergeists do not help us move closer to our goal. Consequently, the actions of supernatural entities play no role in modern scientific discourse. The day someone finds a way to use such an hypothesis to bring clarity to some confusing aspect of nature is the day scientists will embrace the supernatural.
Many of the terms that get thrown around in this discussion - such as testability, falsifiability, or methodological naturalism (MN)- are really just ways of saying that scientists care about predictability and control. Saying that scientists adhere to MN in their work is really just a shorthand way of saying that science is a very pragmatic enterprise, and that the naturalistic hypotheses are the ones that have historically proven useful to scientists. It is a phrase that accurately describes the way scientists approach their work, and it survives because the only alternative - methodological supernaturalism - has proven itself time and again to be utterly ineffective in bringing scientists closer to their goal.
I think my description will seem obvious to any practicing research scientist. Indeed, I think it is obvious to most people who have devoted any thought to the matter, with the possible exception of that small subset of philosophers who see their job as the complexification of fundamentally simple questions.
I was moved to state this plainly because of this bizarre post up at IDtheFuture, written by Paul Nelson. I say bizarre because the arguments he is making are so bad that it is simply impossible to accept that Nelson really believes what he is saying.
Nelson recoutns a visit he received from the historian Ronald Numbers. At that time Numbers was working on his book The Creationists and wished to have a look at some primary source material Nelson possessed reagrding early twentieth century creationists. Early in his post, Nelson writes:
The philosophy of science program at Pitt is one of the best in the world. I had struggled through difficult but deeply rewarding courses with Carl Hempel, Adolf Grünbaum, Jim Lennox, and others, where the question of the definition of science often came up. I observed to Ron that the philosophers (and scientists) I knew best did not agree about whether design by a non-human intelligence qualified as a scientific explanation.
I'm sure Nelson meant to refer to a supernatural intelligence rather than a non-human intelligence. After all, it's perfectly acceptable to refer to animal intelligences in explaining some particular phenomenon.
Could the hypothesis of a supernatural intelligence ever be scientific. I doubt it, but I won't completely rule it out. In principle you could hypothesize a designer with specific supernatural abilities who is also possessed of certain clearly defined motivations and goals. Given such a hypothesis you might be able to say that certain sorts of observations could plausibly be atrributed to the action of this designer while certain other sorts of observations could not be so attributed. You might even be able to make some prediction based on your understanding of the designer's attributes. On the other hand, a carefully circumscribed supernatural designer begins to look an awful lot like a natural law, but still, I won't dismiss this possibility out of hand.
In the context of evolution/ID disputes, however, this is moot. The ID folks are adamant that, to the extent that ID is science, it does not allow any inference to be drawn at all about the nature of the designer. One reason they are adamant on this point is that they know full well that the natural world as we find is not at all consistent with the idea of an all-powerful and all-loving designer. Reconciling the natural world with the Christian God requires so many ad hoc hypotheses that such a designer immeidately loses all value as a scientific hypothesis.
But this is a mere warm-up. The real silly parts are still to come...
On the one hand, Charles Darwin had refuted the theories of special creation of the early 19th century -- and thus such theories were testable, not least because they had been tested and falsified. On the other hand, however, the strong positivism that permeated the atmosphere of the 10th floor of the Cathedral of Learning, the home of the history and philosophy of science program at Pitt, often held that “supernatural” explanations were untestable in principle.
But if such theories were untestable in principle, why did so many of my professors, from both philosophy and biology, talk at length about data that did or did not support Duane Gish's creationism, or “scientific creationism” generally (au courant at the time because of the various “balanced treatment” cases in US federal courts). If Gish's arguments could be countered by evidence, then the dialectic of science was already fully engaged. Whatever evidence can challenge, evidence can support. Right?
The problem, of course, is that Gish made a great many arguments. Some of those arguments dealt with matters of science, and those arguments were both testable and shown to be wrong. Other of his claims dealt with bald assertions of supernatural action, and these were not scientific. For example, Gish was fond of arguing that the best evidence from the relevant branches of science implied that the Earth was on the order of thousands of years old. That's a perfectly scientific assertion, and was shown conclusively to be wrong. Likewise for many of the assertions Gish made about the fossil record. But Gish made other assertions that were plainly not testable. For example, that the universe was created instantaneously by God via mechanisms that are no longer in effect today. That is plainly unscientific.
This point is not complicated, and it has been made times before. I am baffled that Nelson could have overlooked it.
Intelligent causation, I said to Ron, seemed to me to have been unjustifiably excluded from the roster of candidate hypotheses for the origin of life. Life could have been designed. That might have happened, as an empirical possibility, and whatever is possible ought not to be excluded from science a priori. (Some possible states of affairs might turn out not to be the case, of course, but that is a matter for empirical inquiry, not definitions.)
Of course design is possible and could have happened, Ron said to me, tucking into his meal. That's not the problem.
This answer stunned me, and today, almost 23 years later, I can still experience the sense of amazement and shock. One grows accustomed to positivism after a while, and the familiar “science” and “religion” categories had been well-buttressed by multiple lines of argument from very bright people indeed on the 10th floor (albeit with the glaring inconsistencies mentioned above, e.g., 'Wait until Duane Gish sees this new transitional fossil!' -- and with a long historical record of shifting definitions and practices of science shoved to one side). I fumbled out a reply to Ron: But that's not fair, I protested. Where was the justification?
Ron shrugged. You're right, he continued, it isn't fair. (Emphasis in original)
Maybe I'm just a closed-minded skeptic, but I don't believe for a second that Nelson was stunned by that answer. After all, what other answer is possible? Has anyone in the history of the universe ever denied the bare possibility that the world is the product of intelligent design? I'm as hard-core an atheist as you're likely to meet, but I think it's such a live possibility that I spend an inordinate amount of time reading what religious people have to say on the subject. And the possibility of design has nothing to do with positivism, or definitions of science and religion or anything else.
So is it unfair that scientists do not accept supernatural design as an acceptable scientific hypothesis? Only in the same sense that it is unfair for a plumber to dismiss out of hand the gremlin theory of drain clogs. The plumber has unclogged a lot of drains, but has never once found it helpful to hypothesize a gremlin in the pipes as the cause of the clog. Likewise scientists have never once found it helpful to invoke a supernatural entity in pursuing their goals. So how is it unfair for them to leave that assumption out of their work?
Sadly, we now come to the part of Neslon's essay that I found especially vexing:
But think about it this way, he went on. Why is it that when a batter in baseball hits a foul ball, he has to stay at home plate (assuming no one catches the ball)? Why can't he run to first base?
If you're going to have a game, he continued, you've got to have some rules. For a long time now -- really from the middle of the 19th century -- one of the rules in science has been that the hypothesis of supernatural design is excluded from scientific discourse as a candidate explanation. Just as in baseball, where the first and third base lines define the field of play, in science one of the defining rules has been that the hypothesis of design, although quite possible, falls wholly outside the lines of admissible discourse.
Ron then referred me to Neil Gillespie's classic treatment, Charles Darwin and the Problem of Creation, where this problem is much discussed. The exclusion of design is long-standing, Ron concluded, and unlikely to change. That's just the way the game is played nowadays.It's not fair, he said, but those are the rules.I couldn't think of any reply to this -- after all, a rule is a rule is a rule -- and so our conversation moved on.
I hope Numbers didn't really say this, but if he did I can only shake my head sadly and suggest to people that they not learn their science from historians. The analogy of science to a game, with MN as an arbitrary rule within that game, is a very bad way of putting things.
Completely left out of Numbers' description is the fact that science has specific goals in mind. As already discussed, the convention of MN is just a reflection of the sorts of hypotheses scientists have found useful in several centuries of work.
Unfortunatly, this failure to recognize that science is a goal-directed enterprise is very common, in my experience, even among otherwise very well-educated people. I have had many religious people present to me the argument that science tries to discover the truth about nature, God is part of that truth, therefore God should be part of science. This fundamentally misses the point. Science isn't really about ultimate truth. It's about a more practical sort of truth.
Two quick examples should help make the point. First, is it true that the planets orbit the Sun and trace out a ellipse as they do so? Well, all we really know is that they hypothesis that they do has allowed us to make so many successful predictions that it seems reasonable to conclude that it is true. That's what I mean by a practical sort of truth.
Second, consider Newton's law of gravitation - the one that says that the gravitational force between two masses is proportional to the product of the masses and inversely proportional to the square of the distance separating them. Question: How do we know that 2 is the correct exponent to have on the bottom of that fraction? If used the exponent 2.00000000001 or 1.99999999999 we would get the same predictive consequences, at least as far as our ability to measure things is concerned. So why do we assume that 2 is the correct exponent? Answer: We don't. What we know is that 2 is the simplest exponent we can use that allows us to make accurate predictions. No room for ultimate truth here.
Why do scientists believe that simple theories are better than complicated theories? Not because simple theories are more likely to be true in some uoltimate sense. Rather, it is because simple theories are more likely to be useful than complicated theories.
Now, does this mean that science has no role to play in making a case for atheism? Well, yes and no. But we'll save that for a future blog entry.
Nelson concludes with his standard complaints about scientists rigging the game and about how naturalists try to rule out ID by definitional fiat and about how people should let the evidence decide. Blah blah blah.
The situation is actually very simple. If Nelson or any other ID advocate believes that science ought to introduce supernatural thinking into its standard repertoire than the test they have to pass is very simple: Go discover something. Stop with the abstract philosophizing, stop levelling bogus charges about the bigotry and closed-mindedness of mainstream scientists, and stop whining about just wanting to follow the evidence wherever it leads. Scientists have given all due consideration to such evidence as ID folks provide, and they have rightly found it worthless. If Nelson believes they have made an error, let him go into the lab and prove them wrong in the only currency scientists care about: progress towards taming the chaos of nature.