Formal Logic 'Or'

Question 1

When ‘or’ is the logical operator what is it called?

What symbol do we use?

2 Example sentence

Answer 1

two sentences connected by ‘or’, the logical operator is called a ‘disjunction’

We use the ‘v’ symbol

• Labour wins the election v the Tories win the election. (exclusive)*
• We Will go to the beach or the mountains (inclusive)*

Question 2

2 types of truth conditions for ‘Or’

Answer 2

‘Inclusive Or’ - A v B is true if either A is true, or B is true, or both A and B are true.

‘Exclusive Or’ - A v B is true if either A or B is true but not both

Inclusive or is the default

Question 3

Truth Table for Inclusive Or

Answer 3

(A v B) & ∼ (A & B)

Question 4

Exclusive Or truth Table

Answer 4