Here is a talk.origins reply to the claim that evolution is tautological:
According to Popper, any situation where species exist is compatible with Darwinian explanation, because if those species were not adapted, they would not exist.
That is, Popper says, we define adaptation as that which is sufficient for existence in a given environment.
Therefore, since nothing is ruled out, the theory has no explanatory power, for everything is ruled in.
In other words, in the actual world people say that all creatures are what they are because they have “evolved.” But in any possible world, say, in the world in which lions had horns and chipmunks sang songs, the conclusion would be the same, too: these creatures, too, must have evolved. Is there any world in which the claim that things presently existing have arrived there by means of evolution cannot be made?
A certain species of birds produces two offspring. If the year is good and rich with food, then both survive. If the year is bad, then the firstborn sibling will kill the secondborn. Now this is very interesting, to be sure. We can see how this strategy may increase reproductive fitness over an alternative strategy in which infanticide is not condoned, and the birds wait until the first chick is fully weaned. But first, we don’t know if this strategy is globally efficient: perhaps if the birds produced three offspring or had more sophisticated powers of foresight, such that they could determine how good the coming year would be, then their fitness would increase still more.
Second, how do you jump from this observed behavior to the idea that this behavior has “evolved”? Well, “obviously,” these birds were not specially created. More important, however, is that they are not human and are therefore stupid. They could not have reasoned their way toward efficiency but could only have arrived at this somewhat efficient reproductive strategy by millions of years of blind trial-and-error.
This already presupposes that trial-and-error is powerful enough to solve even inventive technological problems. This is evolutionary theory’s worst presumption.
So, it may be true that evolution “rules out the existence of inefficient organisms when more efficient organisms are about.” Also, if 3,000 years ago the world was teeming with life but today most of the world was barren, then this would support the hypothesis that living things were created and in addition by an incompetent creator. But that still leaves a huge number of possible worlds whose emergence is “explained” by evolution with a glib “evolution did it.”
Genes “will tend to be more often transmitted insofar as what they deliver is better ‘engineered’ to the needs of the organisms in the environment in which they live. And you can determine that, within limits, by ‘reverse engineering’ the traits to see how they work.” But this is the very research program of intelligent design! By all means, study these biological systems, such as chemical robots within cells, and how they enable the organism to work and reproduce. All that’s missing is the proper interpretation (is this structure evolved or was it ID’ed?) of the common project.
Again, evolution is not a “science” in a double sense.
First, all science looks for regularities, causal laws. Evolutionary theory is merely history, dealing with unique non-repeatable events.
Second, almost nothing is known about these events, be they mutations or occurrences of design.
I fully realize that what I am asking of evolutionary biologists is impossible for them to produce. But then this is a dead discipline. Quit your jobs and become economists or something.