Chapter 4 – Deductive reasoning

Reasoning from given information that is assumed to be true to derive conclusions that necessarily follow from the information.

Reasoning from knowledge of specific instances and examples to derive generalisations that are probable but not certain.

A type of everyday reasoning that is based on a person’s relevant knowledge and experience rather than on the formal rules of logic.

A type of deductive reasoning that is based on statements or propositions that take the form “If p…then q”.

A system of formal rules devised by logicians that enable valid arguments to be developed from simple statements (propositions) that are linked by logical relations such as if…then, and, or and not.

Statements or propositions that are given and are assumed to be true, from which conclusions can be drawn that may be valid or invalid.

Logical rules that can be applied to premises to determine whether an inference is valid or invalid. For example, modus ponens (from the Latin meaning “mode of affirming”) is a rule which states that given “If p then q” and given that “p” is true, we can infer that “q” is also true by way of a valid conclusion.

Mental representations of possible states of the world that capture the meaning of information in given premises. According to mental models theories of reasoning, people draw inferences based on these models of possibilities.

The idea that the mental models that people construct for given information only capture true possibilities and not false possibilities.

These are a type of reasoning problem that are composed of two premises and a conclusion. The premises and conclusion include the categorical expressions “all”, “no”, “some” and “some…not”, which are referred to as quantifiers.

A rule of thumb that is undemanding of cognitive resources and that often succeeds in producing answers that are correct or approximately correct.

The tendency on abstract versions of the Wason selection task for people to choose to turn over cards matching the items that are mentioned in the given conditional rule irrespective of the presence or absence of negations.

These are terms such as “must”, “should” and “may”, which when used in conditional rules specify obligations and permissions.

In syllogistic reasoning this is the tendency to accept invalid but believable conclusions and to reject valid but unbelievable conclusions.

In syllogistic reasoning this is the tendency for people to endorse conclusions based on the quantifiers used in the premises rather than on the logic of the argument.

In syllogistic reasoning this is the tendency for people to endorse conclusions based on the order of terms in premises rather than on the logic of the argument.

The monitoring and control processes that determine the processes and strategies that are deployed in reasoning as well as the amount of time and effort that is devoted to deriving a solution to a given problem or task.

The idea that people’s rationality is limited by cognitive constraints and environmental constraints such that they are as rational as they can be when reasoning under these limitations.

Finding a solution to a problem that is good enough to achieve a goal but is sub-optimal because humans have bounded rationality.

The idea that human reasoning should be judged as “correct” or “incorrect” according to how closely its outputs match established norm and standards such as those of logic or probability theory.

In informal reasoning this is the tendency to interpret information in a way that aligns with one’s own beliefs or to generate justifications or arguments that support those beliefs.