Logical Thinking

Logical thinking is the ability to consider a set of premises as true for the purposes of reasoning and to derive a logically valid conclusion from them. A logically valid conclusion is a conclusion that is necessarily true if the premises are true. The critical part of such reasoning is the ability to distinguish between conclusions that are necessarily true and conclusions that are possibly true. One can see this distinction by looking at an example from conditional (if-then) reasoning, which is probably the most extensively studied form of logical reasoning. Given the premises “if P then Q. P is true,” the conclusion that “Q is true” is necessarily true and is thus logically valid. However, for the premises “if P then Q. Q is true,” the conclusion that “P is true” is only possibly true and thus is not logically valid.

Another key component of logical reasoning is that conclusion validity should be independent of the specific content of premises and should only reflect their logical structure. Ideally, logical reasoning should allow people to make valid conclusions that are not dependent on their specific knowledge but apply equally to contents that are completely familiar or even totally unbelievable. For example, reasoning with contrary-to-fact premises should lead to the same conclusions as reasoning with familiar premises. Thus, given the premises “if a feather is thrown at a window, the window will break. A feather is thrown at a window,” the conclusion that “the window will break” is logically valid, even though it is empirically false.

This form of reasoning underlies the understanding of modern science and mathematics, and the development of logical reasoning abilities is of critical interest to both psychology and education. This entry examines key theories and empirical studies that characterize the development of logical reasoning.