In my previous post I argued against an economist's criticisms of scientist's claims on truth. Arnold Kling does a much better job of making a similar criticism stick.
Arnold's argument boils down to this: Scientists sometimes claim that they will soon make particular discoveries or uncover particular knowledge, when in fact there is great doubt about whether they will.
These claims of impending success are common, and commonly wrong. More to the point (as Arnold suggests) these claims are unscientific, and therefore unbecoming to professed scientists, precisely because they are non-falsifiable. There is no theoretically possible method to disprove these claims (at the time they are made).
Science deals exclusively with claims that are (in principle) falsifiable. This is an extremely important part of why science works at all. By limiting scientific inquiry to falsifiable claims science is made testable and, ultimately, meaningful. If I believe that a scientific claim is false, I need only devise an experiment that will demonstrate a conflict or contradiction in order to prove that it is false.
Imagine what would happen if non-falsifiable claims were included under the domain of science. Under such a system scientists would concern themselves with claims that are mutually exclusive, but with no ability to distinguish between the truth or falseness of either. The discovery of knowledge would slow as time and effort were consumed in pointless and unending argument...
This is a concept that I'm sure all scientists are taught at some point early in their education. However, as important and fundamental as falsifiability is, many scientists seem to forget about it, or even become confused about what it means. Take, for example, Richard Dawkins' invocation of Russell's Teapot in support of militant Atheism. The bizarre thing here is that Dawkins uses Russell's Teapot as an example of a non-falsifiable claim, and therefore outside of scientific notice, while he simultaneously argues in favor of militant Atheism - which is a non-falsifiable claim as well. How can a scientist of such standing be so confused about one of science's founding principles?
Note: It is important to recognize that Russell's Teapot may actually be a falsifiable claim, and therefore within the purview of science. If you claim that there is a teapot in orbit, AND describe the orbit and the teapot in sufficient detail, then the claim is clearly falsifiable because the absence of the teapot in the specified orbit could, in principle, be observed. Militant Atheism, however is not a falsifiable claim because it is not possible, even in principle, to observe the absence of a god who can tweak the universe and human observation to achieve whatever end he/she/it desires. Militant Atheism must perforce fall outside of the notice of science.
47 minutes ago