Now let’s consider a disjunctive proposition. Firstly, let’s look at “A frog is an amphibian or a frog is a reptile”.
This happens to be true, whether we use an ‘inclusive or’ or an ‘exclusive or’. This is because only the first of the two disjuncts is true, and when only one of the disjuncts is true, both the ‘inclusive’ and ‘exclusive’ or statements turn out true.
Consider alternatively the proposition “A frog is an amphibian or a crocodile is a reptile”.
This proposition is true under the inclusive interpretation, as both of its disjuncts are true. However, under the exclusive interpretation, this proposition is false, as the exclusive disjunctive compound proposition requires that either the first or the second of its disjuncts are true but not both. In contrast to this, the proposition “A frog is a reptile or a crocodile is an amphibian” is false according to either account of disjunction.