10 April 2006

Weighing the Experts

An anonymous lawyer said, “For every PhD there is an equal and opposite PhD.”

When a theory is debated among expert scientists, how are you to know what to believe? Both sides talk over your head and you have no way, short of becoming an expert yourself, of making a truly informed decision.

Could you just put it to a vote among the experts? See how many believe one way and how many believe the other; the majority must be right. Truth can’t be voted into existence, so that would be a bad decision. What can you do?

Here’s an idea: Don’t believe anything.

If you feel like you just have to know which theory is right–what to believe–then I suggest you become a scientist yourself and join in the search.

But if you just want to know what to teach your kids, how to spend your tax dollars for research, or which textbook to use, then I don’t think you have to believe anything. You just want to know which theory to accept, and you’d do best to go with the theory supported by the majority of scientists, especially if it is a vast majority.

What’s the difference? To believe a theory requires knowledge, time, effort, and study. To accept a theory just means that you act in accordance with it.

Someone might object, “But that’s indecisive and unscientific!” To which one could reply, “It’s actually very decisive: I decided to focus my thoughts on something else and let other people worry about this theory. And of course my decision isn’t scientific; is that a bad thing?”

Then you could point out that we do this with theories every day. Here’s an example:

How many people that are taking medications are taking a drug whose benefits are debated by scientists? The answer is: everyone who is taking medications. So why do they take the drugs if it’s not absolutely clear what to believe? Because they have decided to accept the advice of the majority of scientists who believe that that particular drug is worth taking.

(So swallow the pill and get on with your life.)


david said...

But how do we know what the "vast majority" of scientists believe? Because for every news report that states the vast majority of scientists believe one thing there is an equal and opposite news report.

Aaron said...


That is not the fault of science. It is the fault of the news reporters. They use whatever "scientist" they can get to make their story interesting. I think you have to fail high school science in order to be a news reporter.

BrianJ said...


I think a good rule of thumb is to go to trusted scientific organizations and see what is their view. For example, the National Science Foundation, the CDC, NIH, and the National Academy of Science all publish papers on various topics. You could read those bulletins--which are written for a lay public--in order to learn what most scientists believe on a variety of topics.

For an amusing look at weighing one list of experts against another, read this.