Critical thinking is a mental process of analyzing or evaluating information. Such information may be gathered from observation, experience, reasoning, or communication. Critical thinking has its basis in intellectual values that go beyond subject matter divisions and include: clarity, accuracy, precision, evidence, thoroughness and fairness.
Within the framework of skepticism, critical thinking is the process of acquiring information and evaluating it to reach a logical conclusion or answer. It is synonymous with informal logic. Increasingly, based on research in cognitive psychology, educators believe that schools should focus more on teaching their students critical thinking skills than to memorize facts by rote-learning.
The process of critical thinking responds to many subjects and situations, finding connections between them. It is, therefore, a system of related modes of thought that run across fields like science, mathematics, engineering, history, anthropology, economics, moral reasoning and philosophy.
Critical thinking may be seen as involving two aspects: a set of cognitive skills, and the ability and intellectual commitment, to use those skills to guide behavior. It does not include simply the acquisition and retention of information, or the possession of a skill-set which is not used regularly, nor is it mere exercise of those skills without acceptance of the results.
Methods of critical thinking
Although no hard and fixed sequence of steps is required in critical thinking, the following is a useful sequence to follow:
- Itemize opinions from all relevant sides of an issue and collect arguments supporting each.
- Break the arguments into their constituent statements and draw out various additional implications from these statements.
- Examine these statements and implications for internal contradictions.
- Locate opposing claims between the various arguments and assign relative weights to opposing claims.
- Increase the weighting when the claims have strong support especially distinct chains of reasoning or different sources, decrease the weighting when the claims have contradictions.
- Adjust weighting depending on relevance of information to central issue.
- Require sufficient support to justify any incredible claims; otherwise, ignore these claims when forming a judgment.
5. Assess the weight of the various claims.
- Note that the opinion with the strongest supporting claims is more likely to be correct.
- Mind maps are an effective tool for organizing and evaluating this information; in the final stages, numeric weights can be assigned to various branches of the mind map.
Of course, critical thinking doesn't assure that one will reach the correct conclusions. First, one may not have all the relevant information; indeed, important information may not be discovered (see progress) or the information may not even be knowable (see New Mysterianism). Second, one's biases may prevent effective gathering and evaluation of the available information.
To reduce one's bias, various measures can be taken during the process of critical thinking: Instead of asking "How does this contradict my beliefs?," ask: "What does this mean?"
In the earlier stages of gathering and evaluating information, one should first of all suspend judgement as one does when reading a novel or watching a movie. Ways of doing this include adopting a perceptive rather than judgmental orientation; that is, avoiding moving from perception to judgment as one applies critical thinking to an issue, or using white hat or blue hat thinking and delaying black hat thinking for later stages (see Edward De Bono's Six Thinking Hats).
Secondly, one should be aware of one's own fallibility by: a) accepting that everyone has subconscious biases and so questioning any reflexive judgments; b) adopting an egoless and, indeed, humble stance; c) recalling previous beliefs that one strongly held but, now, rejects; then, d) realizing one still has numerous blind spots.
- What do you mean by_______________?
- How did you come to that conclusion?
- Why do you believe that you are right?
- Where do you get your information?
- What happens if you are wrong?
- Can you give me two sources who disagree with you and explain why?
- Why is this significant?
- How do I know you are telling me the truth?
- What is an alternate explanation for this phenomenon?
Reaching a conclusion
A useful perspective in critical thinking is Occam's Razor. Also called the "principle of parsimony," Occam's razor states that one should not make more assumptions than necessary. In other words, keep it simple. Given the nature of the process, critical thinking is never final. One arrives at a tentative conclusion, given the evidence and based on an evaluation. However, the conclusion must always be subject to further evaluation if there is new information.
William Graham Sumner offers a useful summary of critical thinking:
- [Critical thinking is]...the examination and test of propositions of any kind which are offered for acceptance, in order to find out whether they correspond to reality or not. The critical faculty is a product of education and training. It is a mental habit and power. It is a prime condition of human welfare that men and women should be trained in it. It is our only guarantee against delusion, deception, superstition, and misapprehension of ourselves and our earthly circumstances.
- --Sumner, W. G. 1940. Folkways: A Study of the Sociological Importance of Usages, Manners, Customs, Mores, and Morals. New York: Ginn and Co., pp. 632, 633.
- The Critical Thinking Community
- Paul, R., Elder, L., and Bartell T. 1997. California Teacher Preparation for Instruction in Critical Thinking: Research Findings and Policy Recommendations. California Commission on Teacher Credentialing. Foundation for Critical Thinking, Sacramento California
- Anthropic bias
- Cognitive bias
- Discourse analysis
- Empirical knowledge
- Logical argument
- Logical fallacy
- Magical thinking
- Problem solving
- Scientific method
- Wikipedia's policy and guidelines to reaching a neutral point of view
- The Delphi Report (a.k.a. Critical Thinking: A Statement of Expert Consensus for Purposes of Educational Assessment and Instruction, Executive Summary by Peter A. Facione, Santa Clara University (pdf)
- Tim van Gelder's "Critical Thinking on the Web"
- "Critical Thinking: What It Is and Why It Counts" by Peter A. Facione (pdf)
- Critical Thinking Web Aims to supplement and improve the teaching of critical thinking in universities in Hong Kong by providing online teaching and learning resources on critical thinking.
- The Critical Thinking Community Resources for teaching critical thinking, including syllabi; library; sponsors seminars and conferences.
- "Using Critical Thinking To Conduct Effective Searches of Online Resources" by Sarah K. Brem and Andrea J. Boyes
- Critical Thinking Core Concepts from the "Critical Thinking Across the Curriculum" Project, Longview Community College
- Thinking Critically about World Wide Web Resources, UCLA College Library Help Guides
- Teaching Undergrads Web Evaluation: A Guide for Library Instruction, Association of College and Research Libraries
- Argumentation and Critical Thinking Tutorial by Dr. Jay VerLinden, Humboldt State University -- "Intended to help students in college level critical thinking classes learn some of the basic concepts of the formal logical structure of arguments and informal fallacies."
- "Statistical Literacy: Thinking Critically About Statistics" Milo Schield, Augsburg College (pdf)