Question

In one of your lectures recently, you argued that evolution is unfalsifiable (and therefore not a scientific claim but a logical one).
You referred to the example of the peacock, which supposedly does not seem to us to be the most fit, but it survived and one can find an excuse for why it survived (“the survivor survives”). But you ignored the other parts of evolution.

After all, one can raise theoretical arguments that would contradict evolution:

If there were found an animal that fits no evolutionary pathway whatsoever, that has no genetic similarity to any other organism, and no gradual process that led to it (in fossils, genetics, or embryology) — that would raise serious questions.
– If humans were discovered with DNA completely different from every other creature on planet Earth.
– If we were to see a creature that is an impossible combination of organisms that share no common evolution (say, a horse with wings that function like a bat’s, with no intermediate stages).
– If we were to discover, for example, a rabbit fossil from the Cambrian period (more than 500 million years ago), that would seriously undermine the historical order of evolution, because rabbits are supposed to appear only long after the first vertebrates appeared.
– If we were to discover that the mechanism of heredity (such as DNA) does not allow small cumulative changes, or that it resets itself to its original state in every generation — that is, that there is no possibility of mutations being passed on to future generations — that would contradict the mechanistic basis of evolution.
– If the developmental sequence that emerges from fossils contradicted the sequence that emerges from genetics or comparative anatomy, that would create significant problems. In practice, the three methods reinforce one another.

 
A male peacock with a large and conspicuous tail may indeed be more vulnerable to predation, but if females prefer to mate with such males, then specifically he will pass on more genes to the next generation. That is, a reproductive advantage outweighs a survival disadvantage.
Even structures that seem to us “inefficient” or “strange” may be explained by some other benefit — for example, sexual attraction, deceiving predators, or the result of a genetic/developmental constraint.
So what would falsify it?
If there were found an animal that fits no evolutionary pathway whatsoever, that has no genetic similarity to any other organism, and no gradual process that led to it (in fossils, genetics, or embryology) — that would raise serious questions.