Dewey (1910) was among the first and one of the most influential theorists to describe in some detail what we now typically call “critical thinking.” Dewey describes thinking as occurring on three different planes. First, he describes thinking as being simply the goings on in a person’s mind. At this level, thoughts are generally trivial and inconsequential. Second, Dewey describes thinking as a purely mental event. According to this criterion, perception of a lamp that sits on a desk is not considered to be thinking, but remembering the feeling of riding one’s bicycle down a hill is thinking. The third plane of thinking requires that beliefs must be grounded in some sort of evidence. This plane is actually composed of two different levels of thought. Beliefs for which the basis of their truth has not been considered characterize the first level. An example of this kind of thinking might be the belief common among very young children that the sun actually goes up and down and is in motion across the sky. There is certainly evidence that supports this belief and it is understandable why children would form the belief. But when children have matured and are able to consider the evidence in light of an accurate model of the solar system, they typically replace their previous misconception with a model that more closely approximates what is actually true. It is this final plane of thinking that has formed the foundation of what we now call critical thinking. Dewey (1910) further describes this kind of thinking as being an active belief or knowledge that is held due to supporting evidence.
More recent theorists have sought to clarify what is meant by the term critical thinking and in doing so have provided significant insight into the processes, attitudes and skills associated with critical thought. For example, Brookfield (1987) argues that critical thinking is the dual process by which we call into question the assumptions that form the basis of how we typically think and are then prepared to adjust our behaviour depending on the outcome of the process. He says that we must be able to provide justification for our assumptions as well as judge the rationality of our justifications against an objective standard of some sort; so critical thinking is a metacognitive process involving the introspective examination of our typical or habitual ways of thinking. The other part of the process, according to Brookfield, is that we are able to explore and imagine alternative ways of thinking, or alternative justifications that might lead to different conclusions. Brookfield refers to this process as “reflective skepticism” or “cautious intelligence” (1987, p. 21) about claims to truth. Furthermore, says Brookfield, these two processes do not occur outside of the context of active inquiry in a particular discipline. This active inquiry requires the critical thinker to alternate between analysis and action based on the analysis.
Lipman (1988) asserts that critical thinking is based on clear criteria, such as validity, the quality of the evidence and consistency. It is also an iterative process whereby the thinker seeks to find fault with his or her own reasoning and is aware of the context of the phenomenon in question.
Halpern (1989) describes critical thinking as thinking that is purposeful, reasoned and goal directed and the “kind of thinking involved in solving problems, formulating inferences, calculating likelihoods and making decisions” (p. 5). Similar to Lipman and Brookfield, Halpern observes that critical thinking involves a metacognitive process of evaluating the very process of thinking itself and how the thinker came to his or her conclusions.
Bailin, Case, Coombs, and Daniels (1999) describe critical thinking in very similar ways in that it is goal directed, must meet certain standards, and includes the assessment of reasons. They add the idea that there must be a responsible act of deliberation prior to coming to a conclusion that would include the consideration of other alternative views and their justifications. Bailin et al. also delineate five preconditions to good critical thinking:
- The thinker must have some background knowledge of the concepts, beliefs, or facts related to the topic.
- The thinker must understand the requirements of critical thinking in their particular discipline. They must understand what counts as good evidence or justification and what does not.
- The thinker must have knowledge of key critical concepts such as the difference between necessary and sufficient conditions, how to identify different types of arguments and how inferences can be made from premises.
- The thinker must have an understanding of heuristics or strategies for deliberating such as using Venn diagrams or being able to list the pros and cons of each side of an argument.
- Finally, the thinker must have certain habits of mind or attitudes that lead to a desire to think critically.
Hendrickson, St. Amant, Hawk, O’Meara, and Flage (2008) propose that critical thinking is a process used to come to a conclusion about what to believe or do. They contend that it is more than simple logic, which can be reduced to completely symbolic propositions devoid of any content. Rather, they see critical thinking as being employed towards the practical application of reasoning through considering four basic questions.
- What does the statement claim?
- Is the statement true or false?
- What reasons are there to believe that the statement is true or false?
- How good are the reasons for believing that the statement is true or false?
Based on the review of the definitions presented above, the salient descriptors of critical thinking used for this thesis research included the following:
- that critical thinking is purposeful, or goal directed (Bailin et al., 1999; Halpern, 1989; Hendrickson et al., 2008);
- it is a metacognitive process which leads to the examination of assumptions, rationales, and justifications (Bailin et al., 1999; Brookfield, 1987; Halpern, 1989; Hendrickson et al., 2008; Lipman, 1988);
- it includes the consideration of alternative ideas (Bailin et al., 1999; Brookfield, 1987);
- it is dependent upon the willingness of the individual to engage in the process of thinking (Bailin et al., 1999).