keywords

• a posteriori


  Arguments which depend on sense experience: think of ‘posterior’ – behind/after sense experience. For example, we can only know that oak trees grow from acorns by sense experience, and not by logic.
• a priori


  ‘A priori’ arguments rely on logical deduction and not on sense experience. An a priori argument is prior to / before sense experience.
• inductive


  Arguments which use reasoning in which the premises seek to supply strong evidence for (but not absolute proof of) the conclusion. Inductive arguments are probabilistic.
• deductive


  In a ‘deductive’ argument, if the premises are true, then the conclusion must be true.
• synthetic


  ‘Synthetic’ statements / propositions are those whose truth or falsity are determined by sense experience, for example, ‘William has a hairy chest’.
• analytic


  ‘Analytic’ statements / propositions are those that are true by the meaning of the words used, for example, ‘A bicycle has two wheels’ is analytic because by definition a bicycle is a two-wheeled vehicle. In short, analytic statements are true by definition
• subject


  Any complete sentence contains a subject and a predicate. The ‘subject’ refers to who or what the sentence is about. In the following sentence, the subjects are ‘George’ and ‘The dog’. George played the piano. The dog barked.
• predicate


  The ‘predicate’ gives us information about the subject. In the following sentences the predicates are ‘played the piano’ and ‘barked’. George played the piano. The dog barked.
• premise


  A proposition that supports, or helps to support, a conclusion.
• necessary


  A ‘necessary truth’ is a proposition that could not possibly be false, for example, that 2 + 2 = 4, or ‘squares have four sides’. A ‘necessary thing’ is something that could not possibly have failed to exist, for example, some argue that the laws of mathematics exist necessarily.
• contingent


  A ‘contingent truth’ is a proposition that happens to be true but might have been otherwise, for example, ‘In the UK police cars use blue flashing lights in an emergency’ – it is possible that they could have been red. A ‘contingent thing’ is one which does not exist necessarily and so could have failed to exist. Most things in the universe are said to be contingent, including people – your parents might never have met, for example.