The Anti-Infinity Parade

May 08, 2020

Scientific experts and authority

Somebody posted on Hacker News the Baloney Detection Kit by Carl Sagan. Wonderful reading, as is the full book, Demon Haunted World: Science as the Candle in the Dark.

One person, perhaps trolling, asked

'Arguments from authority carry little weight — "authorities" have made mistakes in the past. They will do so again in the future. Perhaps a better way to say it is that in science there are no authorities; at most, there are experts.'

It'd be interesting to see what is left after applying this consistently to scientific announcements. E.g. much of the pro climate change arguments I see are: all the scientists think it is happening, so it must be happening. Not saying they are wrong, but why should only science get a pass when it comes to argument from authority?

I like to answer such questions seriously, for the benefit of other readers, interested in a serious answer to such a question. This person, in particular, was confused about the meaning of "authority" as used by Carl Sagan. They also forget that people have limited time in their life and can't do everything. You can read my responses to them in the link.

Here, I pose and answer a slightly different question. Suppose you have some scientific question that you want answered, such as "Are humans causing the climate of Earth to substantially change?" You observe the people have different answers to this question. Who should you belief?

The answer depends, to a high degree on what you know. Here I present an simplified algorithm.

  1. If you are an expert in the topic itself. You have the both the skills and knowledge, gained over many years of hard work, to answer this question. You should form an answer. Next, compare your answers with other experts in the field, and debate them if your answer differs.

  2. If you are a semi-expert. Usually, this means you are an expert in some other field. You have some skills to roughly evaluate if experts in this field are talking sense, but you don't have the knowledge or the full set of skills required to answer the question. If you want to spend time on the question, you should read what various experts have to say, critically evaluate them, and adopt the answer that makes most sense to you. Otherwise, do what the non-experts should do.

  3. If you are a non-expert. You neither have the skills or the knowledge to assess which experts are right and which are wrong. You should figure out what the most common answer among the experts is, and just believe it. Your attempts to evaluate the experts will fail. You attempts to come up with an answer yourself will fail.

In all cases, you should ignore what non-experts, or even semi-experts, think is the answer to the question.

What does this algorithm not cover? First, determing who is an expert can be very difficult if you are a semi- or non-expert. This is where, without the aid of good social institutions, there is no real way out.

Second, some scientific questions are connect to political questions, and experts might be biased. Again, there is no easy way out. Generally, in this case, you need to listen to the semi-experts, who don't have a vested interest in answering the question one way or the other, and who have done their best to evaluate the experts.

As in anything to do with humans, there is no method, that does not have edge cases or which does not break down in certain conditions.

Later, the commentator, said

Let's take the Galileo case. There were a consensus of experts on Aristotelian cosmology, the best rational worldview of that day, and Galileo's model did not match observations at that point. So, his proposal was rejected. Obviously, Galileo was right to not listen to the consensus of experts in that case.

So, what makes current scientific consensus different than the Aristotelian consensus of Galileo's day? Why are dissidents wrong to question modern scientific consensus (of which climate change is only one controversial element), but right to question the medieval consensus? In both cases, the consensus meets the then current standard for rational worldview, so we can't use hindsight.

Clearly, the answer is that Galileo was justified in holding onto this answer because he was an expert. Experts should not defer to anyone, even other experts, or even a consensus of other experts. Similarly, there probably are climate change dissidents who are actual experts in the field. But unless, you are a semi-expert, you should not be paying attention to these people when debating policies. Any climate change dissidents, who are not experts, go straight out of the window.