Critical thinking is reasonable, reflective thinking aimed at deciding what to believe and what to do. Knowing how to reflect critically on meaning is fundamental to critical thinking. Before we decide what to believe or what to do, we need to make sure that we have clearly defined the words and concepts that we use to formulate the beliefs that we are assessing, to describe the proposals we are considering, and to frame the problems we are facing and the solutions we are contemplating. Otherwise, we run the real risk that we will end up believing something we should not, doing something that will not succeed, or failing to solve the problems we tackle. In this chapter, we will study some practical strategies for constructing and evaluating definitions. But let us start by discussing in a bit more detail where definitions fit into critical thinking.


Knowing how to construct and evaluate definitions is fundamental to critical thinking itself. If we are trying to decide whether to accept or believe some claim or statement, then we need to make sure that we fully understand what the claim or statement means. We may need to analyze it into elements, contrast and compare it with similar claims, and determine what else accepting or believing it would commit us to. If we are presented with several proposals or plans of action, several options for reaching some end, then before we decide on one of them we need ...

Get A Practical Guide to Critical Thinking, 2nd Edition now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.