Q: what are we evaluating?
theories, hypotheses, assertions
people (is X a scientist?)
social practices (is this practice scientific?)
A discipline is more pseudoscientific the more of the following characteristics it has (pp. 39-40):
doesn't appeal to laws as universal and unchanging (and exceptionless)
doesn't attempt to provide explanations and predictions
is not testable (i.e. verifiable or falsifiable)
is not tentative
practitioners do not exhibit "integrity"
Creation Science does not do well on any of these counts, according to Ruse. (In following discussion, the paragraph immediately after the number is my quick summary of one of Ruse's points. Succeeding paragraphs are my own comments, with occasional reference to Laudan's critique.
Laws. "creation science" appeals to miraculous events, events which violate the laws that currently govern the universe.
First, a quibble which may not affect Ruse's main point. It's not so clear that science must treat laws as "universal and unchanging." For example, in the last several years there have been serious discussions in physics about the possibility that the speed of light may be slower now than it was at the beginning of the universe. Some empirical evidence for this claim has been offered. The claim may or may not turn out to be true, but no one seems to think it's unscientific to even raise the issue! [Perhaps Ruse could argue that a change in a fundamental constant doesn't count as a change in the laws of nature? But that seems implausible, I think; if the value of c changes, then so does the meaning of a law like E = mc2.)
Second, is it so clear that there could not be scientific evidence for a violation of natural law? I think there could (but this is controversial). Suppose I tell you that I can violate the law of gravity any time I please by hovering a foot off the ground. Your immediate response is that I'm crazy, but then I perform several demonstrations, under any conditions you please. Now you'll start looking around for scientific explanations of my feat -- electromagnets, hidden wires, giant fans under the floor . . . but none of these things turns out to be present. At some point wouldn't it be reasonable to conclude that I can violate the law of gravity? And in fact wouldn't it even be reasonable to say that you have scientific evidence that I can do this?
In the previous two paragraphs, I've suggested that science does not necessarily need to be committed to unchanging or exceptionless laws. (Paragraph one addressed the "unchanging" part; paragraph two addressed the "exceptionless" part.) I do think that many people would agree with Ruse's view here. But there can be good reasons for changing our views of what science requires. Consider this analogy: At one time it was a standard view (explicitly defended e.g. by Kant) that science must presuppose a deterministic worldview: even if we couldn't find a cause, we had to assume that there was one. This now seems to have been a mistake: not only can physics admit that some events don't have deterministic causes, but it even seems that we can establish that some events are not deterministically caused (e.g. decay of radioactive atoms). This does not show that scientific laws are violated; instead, it shows that they are probabilistic (or "incomplete" in the sense that initial conditions plus the laws of nature don't completely determine an outcome). But it does show that a characteristic we formerly thought was a necessary condition for being scientific wasn't necessary after all. In Kant's day it was thought that scientific laws had to be unchanging, exceptionless, and deterministic. We have completely abandoned the requirement of determinism as a result of advances in science itself. Perhaps we should also give up on the requirements of being unchanging and exceptionless.
Explanation and Prediction. Ruse suggests that creation science neither explains nor predicts anything. For example, he suggests that evolutionary theory has an explanation of the similarity of the bones in the forelimbs of various species (namely that the species descend from a common ancestor), while creation science has no explanation.
Is it right that creation science offers no explanation? One explanation creation scientists have offered for similarities among organisms is that this is just what one would expect in creatures with the same designer. (Similarly, you might expect to find similarities in the music of a single composer, and in some cases also variations on a single theme.)
(In a way the best examples of phenomena that creationists have a difficult time explaining are examples that seem to be poor engineering solutions to a particular problem: Gould on the panda's thumb, which apparently is a poor device for stripping the bark from bamboo shoots, and thus would seem unlikely on the hypothesis that the panda was designed by an all-knowing and all-powerful creator, but makes perfect sense if evolutionary theory is true, since it is simply an adaptation of an existing feature to a new use, which is "easier" than introducing a new feature from scratch.)
Ruse may have a better case with regard to his claim that creation science doesn't make predictions. It does seem able to make some rather vague predictions: for example, that organisms will generally be well-suited to their environments. But it doesn't offer much in the way of specific predictions. But is prediction really a necessary condition for being scientific? It's not clear that we get much in the way of specific predictions from evolutionary theory either.
Testability. Scientific theories should be testable. Ruse seems to have several distinct criticisms of creation science on this front: (1) Creationists don't make empirical claims, just criticize them, so there's nothing to test; (2) creationists don't actually do any testing of their own claims, just criticism of evolutionists' claims; (3) when confronted with evidence that conflicts with their views, creationists hang onto the views anyway, perhaps introducing some ad hoc hypotheses.
All three claims seem somewhat questionable. (1) As Laudan points out, creationists do make at least some testable claims, e.g. that the earth is only a few thousand years old, that humans and other animals appeared on earth at the same time, etc. (see Laudan p. 49). As Laudan puts it, "these claims are testable, they have been tested, and they have failed these tests."
(2) Attempting to find evidence that conflicts with evolution is a kind of testing, isn't it? True, it's testing evolutionary theory, not creationism itself, but couldn't there be a community of genuine scientists who were devoted entirely to criticizing some existing theory? Suppose there were a group of scientists who devoted their entire careers to attempting to refute quantum mechanics. Would there be any reason to deny that they were scientists just because they didn't have a well-tested positive theory to replace QM with?
[Also: the main reason for "intelligent design" theory seems to be the desire to find a positive way to test the claim that the universe was designed by an intelligent being. Intelligent design theorists claim that they do have positive evidence of intelligent design.]
(3) If Kuhn is correct, then a lot of good science is also characterized by an unwillingness to give up central claims, even in the face of conflicting evidence. In his view, science wouldn't get anywhere if we were always obsessively attempting to test our theories; for much of the time, we need to simply assume the correctness of these theories and make use of them. If there's a difference here, it may be a matter of degree. (And it is also important to distinguish (a) scientific claims from (b) scientific practice from (c) the personal attributes of scientists. Individual scientists may have all sorts of unpleasant and even "unscientific" characteristics which get checked or corrected by the general practices of science.)
Tentativeness. Creationists will hang onto their central views no matter what.
-- and scientists won't? Note that this topic is a repeat of (3) above. Again, see Kuhn on the way "normal science" (as opposed to revolutionary science) works. And also, the fact that some creationists irrationally hang onto certain views doesn't show that the content of those views is unscientific.
Integrity. Creation scientists "use any fallacy in the logic books" to advance their views.
Again we can make the point that this is a description of the personal traits of some "creation scientists." It doesn't follow that the content of creation science is unscientific. (It's strange to think that you can evaluate a discipline by the behavior of individual participants. I would think that to judge a discipline we need to evaluate the way it says participants ought to act, not necessarily how they actually do.) No doubt we could also find plenty of conventional scientists who are not above using fallacious arguments, especially in promoting their views to an audience of nonscientists. (It does seem as though there are a lot of particularly egregious examples in the case of creation science, though.)