The Importance of Critical Thinking
2020-05-01 / Karrie Berglund / Critical Thinking

As a science educator and enthusiast, I am a staunch proponent of critical thinking—now more than ever. What does “critical thinking” mean, and why does it matter?
Let’s start with the meaning first. At its most basic level, critical thinking is objectively analyzing and evaluating facts in order to form a judgment. That is quite dense, so let’s break it down further:
- Objectively: Not influenced by personal feelings or opinions.
For example, if I state that the cat is black, that is an objective statement; it is a statement of fact based only on the cat’s fur color. However, if I state that the same black cat will bring bad luck, that is not an objective statement but one based on an opinion or feeling about the color of its fur.
- Analyzing: Methodically and in detail examining the constitution or structure of something.
Consider the parable of the blind people and the elephant, where several blind people who have never encountered an elephant are using their sense of touch to each study a different part of it. No one person’s observations will provide a complete picture of the elephant; you need to get information from multiple sources.
- Evaluating: Forming an idea of the amount of or value of something.
I may evaluate a tree in terms of how much shade it can provide, how likely it is to fall down, etc.
- Facts: Things that are consistent with objective reality, can be verified, and are supported by evidence.
For example, it is a fact that Earth orbits the Sun. This has been verified by observations over hundreds of years, and there are multiple pieces of evidence that support the statement. It can be verified over and over by making additional observations.
- Judgment: An opinion or conclusion.
To form a logical/rational judgment, all of the above bullet points are essential. It is possible but not advisable to skip one or more of the above and go directly to judgment; we’ve all heard the terms “rush to judgment” and “jump to conclusions.”
Forcibly shutting down most of the economy in reaction to novel coronavirus—a.k.a. Covid-19—to me is an example of a decision being made without enough critical thinking. Starting weeks ago schools closed down, businesses deemed non-essential were ordered to close, and other high impact measures were implemented despite a profound lack of data, widely circulating exaggerations, and outright misinformation.
Dr. John P.A. Ioannidis is a professor of medicine at Stanford University with appointments in statistics, biomedical data, prevention research, and health research and policy. He has published more than 1,000 papers, many of which are reviews of other studies (meta-analyses). He is an example of the critical thinking we need today.
Dr. Ioannidis wrote an article entitled Coronavirus disease 2019: The harms of exaggerated information and non‐evidence‐based measures which was published online April 9, 2020.
Here are some excerpts from Dr. Ioannidis’ article:
“Proper communication and optimal decision‐making are an ongoing challenge, as data evolve. The challenge is compounded, however, by exaggerated information. This can lead to inappropriate actions. It is important to differentiate promptly the true epidemic from an epidemic of false claims and potentially harmful actions.” [...]
“Early reported [Case Fatality Rate] figures also seem exaggerated. The most widely quoted CFR has been 3.4%, reported by WHO dividing the number of deaths by documented cases in early March. This ignores undetected infections and the strong age dependence of CFR. The most complete data come from Diamond Princess passengers, with CFR = 1% observed in an elderly cohort; thus, CFR may be much lower than 1% in the general population, probably higher than seasonal flu (CFR = 0.1%), but not much so.” [...]
“Evidence is lacking for the most aggressive measures. A systematic review on measures to prevent the spread of respiratory viruses found insufficient evidence for entry port screening and social distancing in reducing epidemic spreading. Plain hygienic measures have the strongest evidence. […] Most lives saved may actually be due to reduced transmission of influenza rather than coronavirus.” [...]
“Different coronaviruses actually infect millions of people every year, and they are common especially in the elderly and in hospitalized patients with respiratory illness in the winter. […] Leaving the well‐known and highly lethal SARS and MERS coronaviruses aside, other coronaviruses probably have infected millions of people and have killed thousands. However, it is only this year that every single case and every single death gets red alert broadcasting in the news.”
One obvious example of “red alert broadcasting:” I recently saw a news story with the headline “Coronavirus Has Now Killed More Americans Than Vietnam War.” Attention-grabbing and true: the Vietnam War resulted in 58,220 American deaths. However, the Center for Disease Control estimates that the 2017-2018 flu season resulted in 61,000 influenza-associated deaths—and we have a flu vaccine. Was there a similar headline for the 2017-2018 seasonal flu? I don’t remember one, and I didn’t find one in my recent online searches. So why use such a provocative headline for Covid-19?
We’re already seeing financial implications from the shutdown:
- Huge numbers of lost jobs.
- Many, especially smaller, businesses may not reopen.
- Bankruptcies will surge.
- Tax revenue is already diving.
- U.S. relief legislation will add trillions to our national debt (every American already owes more than $75,000 on a per capita basis).
Social implications are harder to pin down. These are the big questions in my mind:
- What effects will these actions have on student learning, especially for students without the means to access online lessons?
- How many students will fall far enough behind that they will have to repeat a grade because of school closures?
- What effect will this situation have on the suicide rate, especially among teenagers?
- How many people will avoid even going to the doctor because they are afraid of contracting Covid-19 and thus will miss tests that would have diagnosed serious heath issues early enough to take action?
In a StatNews article from March 17, 2020, Dr. Ioannidis wrote that, “... locking down the world with potentially tremendous social and financial consequences may be totally irrational. It’s like an elephant being attacked by a house cat. Frustrated and trying to avoid the cat, the elephant accidentally jumps off a cliff and dies.”
The internet is both a blessing and a curse. It makes it easy and inexpensive to communicate with each other, something especially important during this time of quarantines. However, this easy and inexpensive means of communication does not discriminate, nor does it fact-check; true and false information both circulate over the same channels. Studies have shown that false information actually travels further and faster than true information.
So what can we as individuals do? Be a critical thinker: Gather facts. Be open-minded. Continuously evaluate different perspectives, especially those you think you may not agree with. Don’t simply share an article or post on social media without thinking about it first. Encourage your friends to do the same.