Critical Thinking

Novice Thinker

Many of the youngest and most affluent youth Socrates taught were taught critical thinking—to question all presumptions. He taught them that a leader’s endorsement of an idea does not necessarily make it correct. Socrates taught his students to evaluate every idea based solely on its merits. He was charged with “not believing in the city’s gods, introducing new gods, and corrupting the youth.”¹ As a result, he was sentenced to death by hemlock—a horrible way to die.

Fortunately, times have progressed.

Socrates taught his followers to be critical thinkers. As a result, necessary thinking skills are among the most sought-after skills in the modern economy. A survey of American business leaders found that 93% of respondents agreed that “a demonstrated capacity to think critically, communicate clearly, and solve complex problems is more important than the candidate’s undergraduate major.”. ² Interestingly, many believe they are critical thinkers and support critical thinking. Yet, they demonstrate significant bias in their approaches. Many also have definitions of critical thinking that support their biases.

Defining Critical Thinking

Critical thinking can have variable meanings. A Delphi project defined it as “purposeful, self-regulatory judgment that results in interpretation, analysis, evaluation, and inference, as well as an explanation of the evidential, conceptual, methodological, criteriological, or contextual considerations upon which that judgment is based.”. ³

A layman’s translation of this could be the ability to think about connected ideas thoroughly and independently, basing those ideas on factual evidence. It focuses all our reasoning on solving problems.⁴

A critical thinker is only interested in assessing the validity of an argument (or set of data) as it is, without exaggerating reality in either direction. Critical thinking requires treating opinions (or data) that we favor and oppose objectively and impartially.⁴

Mental Models

There are various mental models as they relate to critical thinking. The most reported models are the Hard Choice Model, first-principle thinking, second-order thinking and consequences, and inversion. Detailing these is beyond this goal, but some input is necessary.

First Principles

Aristotle used the first principles of thinking. It is sometimes called “reasoning from first principles.” The idea is to break down complicated problems into essential elements and then reassemble them from the ground up. It’s one of the best ways for individuals to think for themselves, unlock their creative potential, and move from linear to non-linear results.^5,6

Socratic questioning can establish first principles through disciplined questioning that establishes truths, reveals underlying assumptions, and separates knowledge from ignorance. Socratic questioning generally follows this process:^5-7

Clarify your thinking and explain the origins of your ideas (What exactly do I believe? What exactly do I think this patient’s diagnosis is? Why do I think so?)
Challenging assumptions: How do I know this is true? (What if I thought the opposite?)
Looking for evidence: (How can I support my assumptions? What sources?)
Considering alternative perspectives (What might others think? How do I know I am correct?)
Examining the consequences and implications (What if I am wrong? What are the consequences?)
Questioning the original questions: Why did I initially think that? (Was I correct?)

“From the first principles” is a phrase used in physics to describe building a line of reasoning from the ground up. Consider the fundamentals and make the argument from there. Then, you determine whether the conclusion works. It may or may not differ from what has been done in the past.⁵

“First-principles are kind of a physics way of looking at the world, and that means you… boil things down to the most fundamental truths and say, ‘Okay, what are we sure is true?’…and then reason up from there. That takes a lot more mental energy.”⁶

First principles of thinking includes thinking in terms of simplified steps:

1: identify assumptions.

2: Break down the problem.

3: Create new solutions.

Second-Order Thinking & Consequences

Second-order thinking considers not only the immediate consequences of our actions but also the subsequent effects of those actions. An example may be saving money for a new car. The individual doing so walks into a store and sees that the shoes they always wanted are now on sale. Buying the shoes at that time would be first-order thinking. Second-order thinking would involve the individual remembering the car and how important saving money for that new car is.

When considering second-order thinking, it is essential to understand second-order consequences. Every action taken will have a consequence, and every consequence will have another consequence. In the example above, if the shoes were bought, the individual would now have to wait longer to get a new car, as some of the money spent on shoes could have been applied toward purchasing the vehicle.

Going to the gym and exercising can take away time from your studying and possibly make your muscles sore (first order), but going will help set up a good habit, be good for your health, make you feel better, get you into a good routine, improve your muscle performance, etc.

A final example of being in class is when the impulse to multitask on your phone or computer hits. First-order decision-making could be out of interest to avoid missing out on something if the person decides to search social media on their computer. The consequences could be missing important material in class, distracting fellow students, and not getting the most out of the opportunity. Second-order thinking would suggest focusing as much as possible in class and using the class breaks to search social media. Again, all decisions have consequences.

A final thought to consider in this mental model is to look at the most immediate effects when deciding—the first order. Then, for each effect, the person should ask themselves, “And then what?” to examine the second order of the decision’s consequence.

Inversion

Inversion provides an objective way to explore the problem by thinking of the opposite of what we seek. It is a form of reverse questioning that can help us inquire about our assumptions and beliefs. This gives one a better perspective on the original question, with more clarity and understanding.

It is a simple yet powerful mental model that reveals thinking outside of standard thought patterns. As a result, it provides a different (and often better) perspective on the original question with greater clarity and understanding.

A natural mode of thinking:

What can I do to solve this problem?
What should I do to achieve this outcome?

Thinking oppositely to what we desire is not natural. Our mind only seeks limitations to our assumptions if we consciously try to learn to do so. This requires inverting the query.

For example:

What event(s), behavior(s), or action(s) can prevent me from solving this problem?
What event(s), behavior(s), or action(s) can prevent me from achieving this outcome?

Clinical Reasoning

Clinical reasoning is the process in which the person, interacting with significant others, structures meaning, goals, and management strategies based on clinical data, personal choices, and professional judgment and knowledge.⁸ Students typically have a rigidity of reasoning in their early matriculation in graduate school. However, as they progress through the program, they develop an emerging contextual awareness and eventually develop flexibility in their reasoning processes.⁹ This is typical of all novices. There are various types of clinical reasoning that both novices and experienced clinicians utilize, primarily system 1 and 2 thinking:

System 1 & 2 Thinking

“Dual process” theories of clinical reasoning suggest that two distinct psychological processes are at work when clinicians reach a diagnosis. These are referred to as systems 1 and systems 2 thinking.

System 1 is an intuitive, heuristic style of cognitive reasoning. It requires little conscious control as the clinician relies on past experiences. In other words, it is an informal, intuitive, speculative approach to problem-solving derived from experiences with similar problems. Therefore, it is a faster process, requiring little effort and being less mentally taxing than System 2. Some of the many cautions regarding Systems 1 thinking are that it is mistake-prone, riddled with bias (especially if the clinician is not current with evidence), and has low scientific rigor. Again, the person utilizes past experiences to make quick, low-conscious control decisions.

System 2 is more analytical and systematic. It requires high conscious control and mental effort and is a slower process. It involves a high level of scientific rigor. The person gathers evidence to test their hypotheses. It is an information-processing effort. Thus, it utilizes a hypothetico-deductive reasoning process. It is repeatable. It can be slow and arduous.

Time for action:

Man talking — Answers are provided after the conclusion.

Novices vs Experienced Persons

When comparing a student or novice clinician (one more likely to use system 1 thinking) to an experienced clinician (more likely to use system 2), the following are detailed:⁷

	Student	Experienced Clinician
Approach	Analytical: Hypothetico-deductive	Non-analytical: Pattern recognition
Diagnosis/Hypothesis	Isolated facts	Integrated/ contextual
Knowledge Organization	Redundant/ disorganized	Organized/ efficient
Effort	High (cognitive load)	Low
Steps	Not prioritized	Prioritized
Thinking	Slow	Fast

Experienced only sometimes equates to expert. Things like self-reflection and utilization of colleagues characterize expertise. The combination of systems 1 and 2 thinking and personal input is also something experts learn to adopt—evidence-based efficiency.¹⁰

As a result of his labeling of system 1 and system 2, Dr. Kahneman has been criticized for implying two different systems in the brain (“little men working in the brain for thinking,” as he has said). He agrees that systems are a different concept (like what has already been discussed) and that it is simply easier to discuss in this manner. Others suggest using heuristic and hypothetico-deductive reasoning instead of System 1 and System 2.

In associative learning, there are already-formed physiological connections that a person then uses to associate in System 1. This, then, is often a step toward a person implying causality.

An example that Dr. Kahneman has discussed for fast thinking is using this image:

He typically shows it briefly on a slide. Then he returns to it, discussing associative learning; system 1 processing would cause physiological changes when seeing negative words like ‘vomit.’ Additionally, fast system 1 would associate causality. Thus implying

that bananas cause vomiting. This may even make the reader or viewer temporarily negatively associated with bananas. Processing with Systems 2 is necessary to appreciate that this is simply a presentation of two words, and the causality of the relationship would not necessarily be appropriate.

Conclusion: Critical Thinking

Recall that cognition has been defined as a ‘mental process of acquiring.’ Learning how we learn is complex. Employers often demand critical thinking. A true critical thinker, though, makes the best, most informed decision. Such decisions require a structured process or mental model(s). These reasoning processes help one navigate complex systems, such as a client in a healthcare system. There are many barriers to critically applying clinical reasoning to these complex systems. The clinician should use a variety of mental models, as well as types of learning strategies, to limit bias and other barriers.

Answers

(Answer to Riddle 1)

If the bat costs $1.00 more than the ball and the total is $1.10, then the ball must cost 5 cents, and the bat must cost $1.05

(.05 + 1.05 [1.00 more than the .05 ball] =1.10)

A first-inclination approach may be to say the ball is 10 cents, but if the ball were to cost 10 cents, then both together would cost $1.20

(.10 + 1.10 [1.00 more than the .10 ball] = 1.20)

Intuition (system 1, if you prefer) would incline some to say 10 cents when first seeing this riddle because you haven’t checked and used effort to reason it through (system 2). On the surface, it appears to “make sense” that it is 10 cents.

(Answer to Riddle 2)

“R” can be seen in the middle of March and April but can’t be seen at the beginning or end of either month.

The riddle asks to find the objective, which can be seen in the middle of March and April.

Using Systems 1 thinking, we may think about what climate changes or incidents occur between those two months, but that isn’t it. If we break it down into relative first principles and approaches, what do we know for sure?

March – MaRch

April – ApRil

March is a five-letter word. So is April. Both terms have “R” as the standard letter in the third place from the beginning or in the middle of the words.

References

1. Gill C., The Death of Socrates. The Classic Quarterly, 1973, 23(1):25–28.

2. Epsey M.: Enhancing critical thinking using team-based learning. Higher Education Research and Development, 2018:15–29.

3. Facione PA, The Delphi Report: Executive Summary, 1990:315–423.

4. Thinknetic. Critical thinking and logic mastery: how to make smarter decisions, conquer logical fallacies, and sharpen your thinking. 2021.

5. Urban T. The cook and the chef: Musk’s secret sauce. Accessed January 12th, 2023. https://waitbutwhy.com/2015/11/the-cook-and-the-chef-musks-secret-sauce.html

6. Rose K. Foundation 20 // Elon Musk. Krose, LLC. Accessed January 12, 2023. https://waitbutwhy.com/2015/11/the-cook-and-the-chef-musks-secret-sauce.html

7. Durning SJ, Trowbridge RL, Schuwirth L. Clinical Reasoning and Diagnostic Error: A Call to Merge Two Worlds to Improve Patient Care. Acad Med. Aug 2020;95(8):1159-1161. doi:10.1097/acm.0000000000003041

8. Jones MA. Clinical reasoning in manual therapy. Phys Ther. Dec 1992;72(12):875-84.

9. Furze J, Kenyon LK, Jensen GM. Connecting Classroom, Clinic, and Context: Clinical Reasoning Strategies for Clinical Instructors and Academic Faculty. Pediatr Phys Ther. Winter 2015;27(4):368-75. doi:10.1097/pep.0000000000000185

10. Jensen GM, Gwyer J, Shepard KF. Expert practice in physical therapy. Phys Ther. Jan 2000;80(1):28-43; discussion 44-52.

Riddle 1	Riddle 2
A bat and ball cost $1.10. The bat costs one dollar more than the ball. How much does the ball cost?	What is seen in the middle of March and April that can’t be seen at the beginning or end of either month?