“If you’ve got the truth you can demonstrate it. Talking doesn’t prove it.”
― Robert A. Heinlein, Stranger in a Strange Land

As I watch the news it occurs to me that the art of critical thinking is and has been neglected in today’s education. Carl Sagan wrote about what he called “The Fine Art of Baloney Detection” – he devoted a chapter to the subject – in his book The Demon-Haunted World: Science as a Candle in the Dark. I wanted to share Sagan’s observations with some added commentary to help the coming generation cope with the flood of questionable information they are assaulted with every day. There are 9 tools to add to your reasoning toolbox.

1. Wherever possible there must be independent confirmation of the “facts.” Nowadays we need to be careful with the word “facts.” I would suggest that a fact is a verifiable, undisputed observation, or law. A simple but meaningful example would be the definition of legal or illegal. To do something that is contrary to the established laws of a nation is illegal. It’s the most basic way to understand law. The attempt to rephrase whether an act is illegal in order to spare someone’s or some group’s feelings is foolish at best, and censorship at worst. One of my least favorite phrases is “it is what it is.” Fortunately or unfortunately, this phrase fits this idea. Facts are facts and we should not accept alternative facts that fit a narrative – regardless of political affiliation.

2. Encourage substantive debate on the evidence by knowledgeable proponents of all points of view. The keywords are “substantive debate,” not shouting matches, not violence, and not censorship. If you can’t logically defend your point of view, then you probably shouldn’t be debating. It’s like bringing a rock to a gun fight. Also, a person shouldn’t try to shut down debate because they cannot logically defend their point of view. As stated in previous posts, we have two ears and one mouth because we should listen twice as much as we talk.

3. 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. Saying that most scientists agree on any subject is a great example of this indicator. Consensus does not make an argument. There was once consensus that the world was flat and that “bad or evil vapors” caused most illness.

4. Spin more than one hypothesis. If there’s something to be explained, think of all the different ways in which it could be explained. Then think of tests by which you might systematically disprove each of the alternatives. Don’t be a slave to your ideas or thoughts, and don’t be afraid to read or hear opinions that differ from you own. If you become uncomfortable with your own hypothesis after hearing another – that’s a sign that maybe your original one may need to be reexamined.

5. Try not to get overly attached to a hypothesis just because it’s yours. A hypothesis is simply a way station in the pursuit of knowledge. Ask yourself why you like the idea. Compare it fairly with the alternatives. See if you can find reasons for rejecting it. If you don’t, others will. This can be seen every day in the news with some of the crazy hypotheses that can be picked apart with very little effort – but won’t be because the person who presented it is a celebrity or an academic.

6. Quantify. If whatever it is you’re explaining has some measure, some numerical quantity attached to it, you’ll be much better able to
discriminate among competing hypotheses. What is vague and qualitative is open to many explanations. Of course, there are truths to be sought in the many qualitative issues we are obliged to confront, but finding them is more challenging.

7. If there’s a chain of argument, every link in the chain must work, including the premise – not just most of them.

8. Occam’s Razor. This convenient rule-of-thumb urges us when faced with two hypotheses that explain the data equally well to choose the simpler.

9. Always ask whether the hypothesis can be, at least in principle, falsified. Propositions that are untestable, unfalsifiable are not worth
much. Consider the grand idea that our Universe and everything in it is just an elementary particle – an electron, say – in a much bigger Cosmos. But if we can never acquire information from outside our Universe, is not the idea incapable of disproof? You must be able to check assertions out. Inveterate skeptics must be given the chance to follow your reasoning, duplicate your experiments, and see if they get the same result.