more than 2000 years and held an important place in undergraduate studies in
medieval universities. Aristotle’s logic – his theory of the syllogism – was thought
to be a perfect science well into the 19th century.
Or truth tablePropositional logic
Another type of logic goes further than syllogisms. It deals with propositions
or simple statements and the combination of them. To analyse the newspaper
leader we’ll need some knowledge of this ‘propositional logic’. It used to be called
the ‘algebra of logic’, which gives us a clue about its structure, since George
Boole realized that it could be treated as a new sort of algebra. In the 1840s
there was a great deal of work done in logic by such mathematicians as Boole
and Augustus De Morgan.
And truth table
Let’s try it out and consider a proposition a, where a stands for ‘Freddy is a
spaniel’. The proposition a may be True or False. If I am thinking of my dog
named Freddy who is indeed a spaniel then the statement is true (T) but if I am
thinking that this statement is being applied to my cousin whose name is also
Freddy then the statement is false (F). The truth or falsity of a proposition
depends on its reference.
Not truth table