“Discovering Tautologies Logical symbols may be used in combination, which can help us calculate the truth condition of any logically complex sentences. For example, “p v ¬p”, which produces the following Truth Table:   When a formula only has T’s under it in a Truth Table, it means that it is true in all situations. The sentence “Either it is raining or it is not raining” cannot be false. Logicians call this a tautology. In a tautology, one truth follows from another of necessity only because of the logical syntax. So we know that any sentence with the same logical syntax will always be true. This”