How do you determine the truth value of propositions?
Calculating the Truth Value of a Compound Proposition
- For a conjunction to be true, both conjuncts must be true.
- For a disjunction to be true, at least one disjunct must be true.
- A conditional is true except when the antecedent is true and the consequent false.
Do propositions always have a determine truth value?
A “statement” (or “proposition”) must, by definition, have truth value; i.e., it must be either true or false.
How many truth values are possible in propositional logic?
Classical (or “bivalent”) truth-functional propositional logic is that branch of truth-functional propositional logic that assumes that there are are only two possible truth-values a statement (whether simple or complex) can have: (1) truth, and (2) falsity, and that every statement is either true or false but not both …
How do you know if truth value is true?
In general, to determine validity, go through every row of the truth-table to find a row where ALL the premises are true AND the conclusion is false. Can you find such a row? If not, the argument is valid. If there is one or more rows, then the argument is not valid.
What is a propositional statement that is always true?
A propositional statement that is always true is called a tautology, while a propositional statement that is always false is called a contradiction. For instance, the statement “I will eat my dinner or I will not” is a tautology, because it allows for either instance and therefore is always true.