Critical thinking means weighing up the arguments and evidence for and against. Edward Glaser, who developed a test of critical thinking, defined it in this way (1941)
Critical thinking calls for a persistent effort to
examine any belief or supposed form of knowledge
in the light of the evidence that supports it and the
further conclusions to which it ends.
In other words, Glaser emphasises the importance of:
• persistence: considering an issue carefully, and more than once
• evidence: evaluating the evidence put forward in support of the belief or viewpoint
• implications: considering where the belief or viewpoint leads - what conclusions would follow; are these suitable and rational; and if not, should the belief or viewpoint be considered?
COTTRELL, Stella (2003) The study skills handbook. 2nd ed. New York: Palgrave Macmillan. p. 221