Welcome back to "Doggerel," where I ramble on about words and phrases that are misused, abused, or just plain meaningless.
There's no shortage of these urban legends, and always a shortage of evidence to back them up. That, however, is a complete red herring that develops from the delusion that scientists are more authoritative than evidence.
Charles Darwin and Louis Pasteur are frequent victims of this doggerel. The problem is that the theories they birthed aren't confined to them. The success of a scientific theory is its explanatory and predictive power. Evolution is still the only way to look at biology that ties it all together. It's grown beyond Darwin's knowledge. The same is true with the Louis Pasteur's germ theory of disease: We not only know that germs cause various diseases, we know the various types of germs, how and why many cause disease, and how to combat and contain these diseases. The "alternatives" pitched by the people who tell these stories typically rely heavily on coincidence, or simply don't bother to explain or predict the myriad details the mainline theories do.
That's why deathbed recantations, even if they did happen, are completely worthless. The ultimate authority in science is the evidence. Either a theory works or it doesn't. Theories are not proclamations from on high that can be revoked by royal decree. The only thing that can tear down a theory is evidence that contradicts its predictions. To find that, you have to understand the theory and what it explains.