Related to my last two posts, and our discussion, Sean Carroll turned in an answer to the “What Scientific Ideas Are Ready for Retirement?” His answer? Falsifiability.
Modern physics stretches into realms far removed from everyday experience, and sometimes the connection to experiment becomes tenuous at best. String theory and other approaches to quantum gravity involve phenomena that are likely to manifest themselves only at energies enormously higher than anything we have access to here on Earth. The cosmological multiverse and the many-worlds interpretation of quantum mechanics posit other realms that are impossible for us to access directly. Some scientists, leaning on Popper, have suggested that these theories are non-scientific because they are not falsifiable.
The truth is the opposite. Whether or not we can observe them directly, the entities involved in these theories are either real or they are not. Refusing to contemplate their possible existence on the grounds of some a priori principle, even though they might play a crucial role in how the world works, is as non-scientific as it gets.
Carroll’s reasoning is nuanced and his essay deserves to be read in full.
I’m a fan of Carroll’s, but he seems to be splitting some very fine hairs here. I’m sympathetic to falsifiability in and of itself not being the end all be all of the demarcation of science, but it seems like there needs to be some relation to empirical data. Carroll does give a nod in this direction, but when your theories are never testable, even in principle, it sure seems like you’re engaging in a different kind of inquiry than what has historically been labelled as science.
I also found his disparaging remarks about the critics of these theories to be somewhat off putting. In my experience, when someone feels the need to engage in that kind of name calling, throwing around labels like ‘amateur’ or ‘lazy’, it’s often because they suspect their own argument isn’t strong enough to stand on its on.
Anyway, this demonstrates to me that Baggott wasn’t just arguing against a straw-man when he said that some physicists were beginning to doubt the usefulness of testable predictions.