Criterion 1. Empirical Phenomena.
Empirical refers to phenomena that are directly or indirectly observable. Now ID claims that there is empirical evidence of intelligence, information, and wisdom in nature. Their focus right now is on finding evidence of design in cells. A hypothesis that they’ve latched onto is irreducible complexity (IC). IC is the belief “that certain biological systems are too complex to have evolved from simpler, or less complete predecessors, through natural selection acting upon a series of advantageous naturally-occurring, chance mutations.” Because it is possible to gather empirical data concerning the complexity of living systems, ID meets this criterion.
Criterion 2. Testable Predictions.
A scientific theory generates testable predictions. To be sure, we can test IC by looking for irreducibly complex systems in nature, so ID makes testable predictions. There is not much more to say on this matter. I will add, however, that some have claimed that IC has been debunked because evolution has provided more rigorous, plausible evolutionary explanations for complexity. The fact that proponents of an opposing theory lay claim to a better explanation does not make ID and its IC hypothesis any less testable. The issue of which theory best explains a phenomenon is another matter altogether and has little bearing on the testability issue.
Criterion 3. Falsifiability.
Does ID allow for risky predictions that will allow us to prove that it is false?
Sure. In fact, opponents of ID are hard at work falsifying the irreducible complexity (IC) hypothesis. It’s kind of funny, but this is a good thing for IDers because it means that a major hypothesis of ID is supposedly falsifiable. So, in a way, opponents of ID are helping to guarantee its scientific status by trying to falsify its core tenet. Well, has IC been falsified? Scholars like Ken Miller say yes. He claims that the creation of the bacterial flagellum (a complex, multi-part propeller system) can be explained by natural selection and is thus not irreducibly complex. He has pointed out that if we remove 40 of the 50 separate parts in a bacterial flagellum and left the 10 protein parts connected to the membrane of the cell, those remaining 10 parts may function as a Type-III secretory system. Miller claims that this discovery refutes IC. Miller’s refutation suggests that ID posits falsifiable hypotheses
Criterion 4. Tentative Stance
Scientists should recognize that their theories may one day be proven false. Are proponents of ID willing to accept that their theory may one day be proven false? The idea that ID may be proven false is a HUGE problem here, folks. What sincere believer would be willing to consider that there is no supreme intelligence, or be willing to accept that there is no evidence of divine design in nature? Here we see the danger of tying up theology with science. If you closely ally your religious beliefs with a scientific idea, what happens when that scientific idea is eventually proven false, as so often happens? Tying up religious beliefs with scientific theory is risky. When scientific theories closely allied with religious belief fall, it sends people into a faith crisis tail spin. This is a potential problem, yet I haven’t seen anything which suggests that IDers have not taken a tentative stance.
Criterion 5. Crucial Experiments
Crucial experiments are investigations that allow us to definitively decide between two competing theories, or, in other words, they are experiments that allow us to definitively conclude that a theory is false. This criterion is not an all or nothing issue - a theory is not automatically labeled unscientific if it cannot produce crucial experiments. This issue is a matter of degrees. The more crucial experiments a theory generates, the more rigorous it is. Has ID produced crucial experiments? Not yet. To the best of my knowledge ID is currently limited to “let’s go out and find evidence for IC,” sort of thing. What is lacking is manipulation of the IC process in the laboratory that would allow conclusions like: We manipulated biological system X in our laboratory and, true to our prediction, the system evolved an irreducibly complex mechanism Y. Before ID’s critics start opening the champagne bottles, I wish to point out that macroevolution has the same limitations. There is plenty of evidence supporting macroevolution, but to date it has not generated crucial tests due to limiting factors such as that it takes a very long time for new life forms to evolve.
Sum: For now, ID satisfies the traditional definition of science. It offers an empirical, rational, and testable approach to investigating complex systems. ID must be careful, however. Any attempt to make the supernatural the central focus of ID will render ID non-scientific by traditional standards. ID’s critics should take note that it is decidely anti-scientific to deny ID a voice simply because it challenges one’s favorite theory or because it reminds one of a nonscientific endeavor like creationism. If ID has legitimate discoveries to bring to the table, then let’s hear them out and allow debate, refutation, and criticism to take their normal course. ID will live or die. Either way, we should let the scientific process, not politics, decide its fate.