Here is another fallacious argument:
Science was wrong before
… or equivalent wording.
The argument is that since science is sometimes wrong, the believer’s claim is as likely to be true as one supported by scientific evidence.
The flaw in the argument
Science is a series of provisional truths, backed by evidence, that are amended when better evidence is available. The key word here is “evidence”. In other words, we have a reason to suppose scientifically supported ideas are true. Contrast this with unscientific ideas, where there is rarely any rational reason to suppose they are true. Additionally, the scientific idea that was shown to be “wrong” was often not completely wrong: it often still had utility.
In reality, science has proved the most reliable method we know for evaluating claims and figuring out how the universe works. The appeal to “science was wrong before” is just a smoke screen to disguise the fact that the believer has no evidence for his claim. It does not follow that science should not be applied to evaluate claims, or that unscientific claims are likely to be true.
What they’re missing
As well as being a flawed argument, it also shows ignorance of how science works. Yes, science has been wrong, but the scientific method is self-correcting. And it is always scientists who have unearthed new evidence who do the correcting, never people who ignore the scientific method.
Ironically it also shows up the strength of science and the weakness of believer methods. For example, compare the way scientific errors are discovered and corrected, with what happens in, for example, astrology or alternative medicine. In those fields no errors are ever corrected for the simple reason that no one ever critically tests those beliefs to see if they even contain errors. Errors are a permanent feature of those beliefs. Error recognition and correction is a strength of science.
There are several versions of this fallacy. For example, believers often cite Newton being proven wrong by Einstein. Of course, Newton’s calculations are close enough for anything other than close-to light speed calculations – that’s why Newton’s formulae are used by NASA.
Alternative medicine proponents will often note that evidence-based doctors are sometimes wrong in their diagnoses, as if this means altie therapies work. Doctors are fallible and our knowledge is incomplete, but the evidence-based approach has led to huge advances and improvements in healthcare, unlike alternative treatments that have achieved virtually nothing.
This fallacy is related to, but is slightly different from, the appeal to other ways of knowing.