The surprising archenemy of critical thinking: Armchairs

In the midst of the current coronavirus crisis, I have seen several articles talking about “armchair epidemiologists”–and despising them, of course. And I have just realized how damaging this term is.

Whenever something important happens, people learn a bit about it, talk about it, theorize, discuss. And of course, not being experts, they make mistakes. It’s easy to laugh about the armchair generals bred by distant wars, the armchair political strategists arising before every election, and the armchair nuclear scientists surging from every nuclear mishap. And of course, the current armchair epidemiologists discussing the advantages and disadvantages of “flattering the curve”.

And of course, it’s true that most of these people are wrong and uninformed, when you compare them to the true experts.

But then, we also fill our mouths about the importance of critical thinking. That we must not just accept what we are told, but evaluate it. That we must try to learn about the world and make our own opinions. How do you do that? You learn a bit, talk about it, theorize, discuss. You make mistakes, and others tell you about them. You correct accordingly (or you don’t).

What’s the alternative? To shut up and do as you’re told. Is that the society we want?

For one, I’m loving all those people filling twitter with their thoughts, their graphs, and their theories. And with their strong opinions, overinterpretations, and mistakes. That’s what critical thinking smells like.


To laugh often and much; To win the respect of intelligent people and the affection of children; To earn the appreciation of honest critics and endure the betrayal of false friends; To appreciate beauty, to find the best in others; To leave the world a bit better, whether by a healthy child, a garden patch, or a redeemed social condition; To know even one life has breathed easier because you have lived. This is to have succeeded.

by Ralph Waldo Emerson
Seen at The Flavell Lab

A not-so-bad default way to cite relevant literature in the introduction of a scientific paper

A good introduction summarizes and motivates the question asked in the paper, and tells us what has been done about it and what is missing. In the process of this explanation, citations to the relevant literature are naturally intermingled.

But doing this neatly is often difficult. While probably a failure on the writer’s side, sometimes there is a relevant chunk of literature that must be aknowledged in the introduction, but does not naturally fit in the “story” one is writing.

What I do in these cases is to twist the story to include a reference to that chunk of literature. When this works, it’s great. But sometimes it does not quite work, and one ends up with a disorganized introduction.

Reading “A Theory of Credibility”, by Joel Sobel, I find a solution which maybe is sub-optimal, but which I find neat. He first writes a nice and focused introduction, with no references at all. Then he dedicates a single paragraph to explicitely acknowledge previous work:

Recent papers by […] were the first to present models in which […] My paper owes much to this work.

Not as elegant as other introductions. But it allows to keep the rest of the intro focused on what the reader needs to understan the paper, and not on what other researchers want you to acknowledge.

Book: E. coli in motion, by Howard C. Berg

Amazing book. I took it with the idea to read a chapter from time to time. When I do this, I rarely go beyond the first pages. This time, I could not stop reading until I finished the whole book (literally: I read it in one sitting).

Two fragments I loved:

The habitat and life cycle of E. coli in two (beautiful) sentences:

E. coli lives a life of luxury in the lower intestines of warm-blooded animals, including humans. Once expelled, it lives a life of penury and hazard in water, sediment and soil.

About diffusion (perhaps shame on me, but this made me understand something I never understood before):

The major take-home lesson is this: diffusive transport over small distances is very efficient, while diffusive transport over large distances is very inefficient. Diffusion times increase as the square of the distance. Thus, a small molecule in water can diffuse the width of E. coli (1 μm) in a few milliseconds. To diffuse the width of your finger (1.5 cm), it takes about a day.