From our section above, let’s look at the compound proposition: “A frog is an amphibian and a crocodile is a reptile”, and try to piece together whether or not it is true.
This will be true, because both conjuncts themselves are true.
But suppose we switch the predicates and make new sentences with the same conjunctions, for example: “A frog is an amphibian and a crocodile is an amphibian” and “A frog is a reptile and a crocodile is an amphibian”.
Both of these conjunctive propositions turn out to be false. The first is false, as its second conjunct is false. Despite the fact that the first of these two conjuncts is true, it must be remembered that the truth of a conjunctive proposition relies upon the truth of both of its conjuncts. The second is false too, as neither of its conjuncts are true.