Modern classification of Propositions — Aim of modern classification, Kinds of simple and compound propositions and basic truth tables for compound propositions

"If the accused was at the scene, and the weapon matches, then he is guilty." Try forcing that single sentence into the traditional All-S-is-P mould and it simply will not go — it is built entirely out of smaller propositions glued together with ‘and’ and ‘if…then…’. Modern logic stopped trying to force every sentence into one subject-predicate shape, and instead classified propositions by how they are built — simple, or compound out of simpler ones — which is exactly what lets you test an argument like that one mechanically, with a truth table.

In two minutes

The modern classification of propositions abandons the traditional subject-predicate mould and instead sorts propositions by their internal logical structure into simple propositions (with no logical connective) and compound propositions (built from simpler propositions joined by connectives such as negation, conjunction, disjunction, the conditional and the biconditional), whose truth or falsity can then be mechanically checked with a truth table.

The rest of this chapter

The full explanation, the cheat sheet, every previous-year question at every mark weight, the quiz and the answer skeletons are part of Logic – I on LexBlox Semester. Sign in to unlock the subject, or read Module 1 of Legal Language and Writing free.