In the abstract, it might be tempting to imagine that irreducible complexity simply requires multiple simultaneous mutations - that evolution might be far chancier than we thought, but still possible. Such an appeal to brute luck can never be refuted... Luck is metaphysical speculation; scientific explanations invoke causes.
Random mutations much more easily debilitate genes than improve them, and that this is true even of the helpful mutations. Let me emphasize, our experience with malaria’s effects on humans (arguably our most highly studied genetic system) shows that most helpful mutations degrade genes. What’s more, as a group the mutations are incoherent, meaning that they are not adding up to some new system. They are just small changes - mostly degradative - in pre-existing, unrelated genes. The take-home lesson is that this is certainly not the kind of process we would expect to build the astonishingly elegant machinery of the cell. If random mutation plus selective pressure substantially trashes the human genome, why should we think that it would be a constructive force in the long term? There is no reason to think so.
I want to pause here and talk about this notion of consensus, and the rise of what has been called consensus science. I regard consensus science as an extremely pernicious development that ought to be stopped cold in its tracks. Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled. Whenever you hear the consensus of scientists agrees on something or other, reach for your wallet, because you're being had. Let's be clear: the work of science has nothing whatever to do with consensus. Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world. In science consensus is irrelevant. What is relevant is reproducible results. The greatest scientists in history are great precisely because they broke with the consensus. There is no such thing as consensus science. If it's consensus, it isn't science. If it's science, it isn't consensus. Period.
To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I confess, absurd in the highest degree...The difficulty of believing that a perfect and complex eye could be formed by natural selection , though insuperable by our imagination, should not be considered subversive of the theory.
Teaching students the evidence for and against Darwinism is not the same as teaching intelligent design. The U.S. Congress has officially endorsed teaching students 'the full range of scientific views' about Darwinian evolution.
Genetics might be adequate for explaining microevolution, but microevolutionary changes in gene frequency were not seen as able to turn a reptile into a mammal or to convert a fish into an amphibian. Microevolution looks at adaptations that concern the survival of the fittest, not the arrival of the fittest... The origin of species — Darwin’s problem — remains unsolved.
No fossil is buried with its birth certificate. That, and the scarcity of fossils, means that it is effectively impossible to link fossils into chains of cause and effect in any valid way... To take a line of fossils and claim that they represent a lineage is not a scientific hypothesis that can be tested, but an assertion that carries the same validity as a bedtime story—amusing, perhaps even instructive, but not scientific.
Regardless of one's point of view, it's quite easy to see that Darwinism is not in the same league as the hard sciences. For instance, Darwinists will often compare their theory favorably to Einsteinian physics, claiming that Darwinism is just as well established as general relativity. Yet how many physicists, while arguing for the truth of Einsteinian physics, will claim that general relativity is as well established as Darwin’s theory? Zero.
The idea that one can go to the fossil record and expect to empirically recover an ancestor-descendant sequence, be it of species, genera, families, or whatever, has been, and continues to be, a pernicious illusion.