Critical Thinking

Need for Critical Thinking

Before discussing our need for, or the  benefits of critical thinking, it’s important to have an idea of what we mean by critical thinking. There are many definitions. I like the definition by Edward M. Glaser in An Experiment in the Development of Critical Thinking (1941) where he calls critical thinking, “A persistent effort to examine any belief or supposed form of knowledge in the light of the evidence that supports or refutes it and the further conclusions to which it tends.”

As a teacher ( I tend to use more layman’s terms. I might tell my students that critical thinking is the ability to think without being bound by the prejudices of tradition or emotion and to be open-minded to views other than your own. I could go through the entire curriculum and give examples of the benefits of critical thinking in each course but that would take forever and not necessarily be of interest to all readers. So, I will only concentrate on the two benefits of critical thinking that I feel are of life and death importance for education and for the well being of society.

Critical thinking helps us to realize and accept that there can be many sides to, opinions about, or options connected with an idea or a course of action. In The Argument Culture: Stopping America’s War of Words (1998) linguist Deborah Tannen rejects the accepted notion that, “There are two sides to every question” as it does not define “open-mindedness and expansive thinking.” To rephrase for clarity, she believes, as do I, that there can be many sides to a question. Open-mindedness is an essential component and benefit of critical thinking.


This open-mindedness component of critical thinking helps us to learn and plan beyond our traditions and our cherished beliefs. In Collapse: How Societies Choose to Fail or Succeed (2005) Jared Diamond shows how societies that lacked critical thinking collapsed. Societies that choose to only trust tradition and not put forth that “persistent effort to examine any belief or supposed form of knowledge in the light of the evidence that supports or refutes it” risk serious consequences. 

Only by examining our most cherished beliefs and traditions in the clear light of critical thinking can we hope to avoid destroying our society and our world.

Separating fact from fiction

Critical thinking is most important when trying to separate fact from opinion. By thinking critically you can chart a course of action when the facts are in flux or in dispute. Critical thinking can also tell you when to shut up and not waste time trying to use logic to convince someone of a different position; because you are dealing with an emotions driven person or group which is threatened by facts. For example:

Climate change, and drug or education policies (just to name few examples) all need critical thinkers. Those who deny climate change refuse to look at long term studies of climate. They refuse to believe in the scientific method which does teach us that you keep a belief or hypothesis as long as it is applicable. Should your hypothesis be proven wrong by later investigation, you get rid of the old hypothesis and follow a new one. Change frightens many who don’t think critically.

Climate change deniers frequently confuse weather with climate. This fosters a mentality that says, “There’s nothing we can do about it so we’ll do nothing.” This endangers future generations. Because, even if the scientists are proven wrong for telling us that humans are changing our climate, we aren’t doing enough to protect ourselves from the weather and climate we are currently having. Between hurricanes and flooding and drought, who needs doomsday predictions?

Drug policy and education policy frequently abandon critical thinking for two obvious mistakes (there are many other mistakes of logic which need critical thinking but I’ll try to be brief). One mistake is correlation does not always mean causation (i.e., just because two sets of numbers or facts seem to go together doesn’t necessarily mean that one caused the other). The other mistake, which is related, is ‘post hoc, ergo propter hoc’ which means ‘after the thing, because of the thing’.

Those who fear marijuana legalization often quote a statistic which says something like, ‘90% of all heroin addicts started their drug use by smoking pot. Banning pot keeps our drug addition statistics from running wild’. They called pot a gateway drug. This is a dangerous oversimplification and misguide approach to a serious problem. A critical thinker could show the silliness of that ‘gateway drug’ argument by countering with (using the same skewed logic): ‘90% of all heroin users drank milk, therefore if we ban milk it will reduce heroin addiction’.

Post hoc ergo propter hoc

As an Algebra teacher I constantly fought against the post hoc ergo propter hoc fantasy which states that ‘the vast majority of those who were successful in college were successful because they took Algebra in high school. To get more kids into college all students must study Algebra’. They called Algebra a gateway subject.

I always argued that Algebra was an indicator subject. Those who voluntarily took Algebra in high school and understood it, showed a better chance of doing well in college.

My students who hated Algebra because they weren’t grounded in basic math or critical thinking didn’t go on to do well in college.  Because they lacked the primary prerequisite skills sets to succeed in college.

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