Deductive Logic Flashcards
To learn the vocabulary words for the Homework Quiz 6
Categorical proposition
Can be regarded as an assertion about the relations among classes.
All apples are fruits. The proposition explains that all items in the subject, apples, are included in the predicate, fruits.
Copula
The links are subject and predicate. In all examples so far, the copula has been affirmative. We said that S is P. But the copula can also be negative, as in propositions.
the sky is blue. The copula is not the same as the “is” of identity.
Whales are not fish.
Copula is a verb and the terminology is..
Are, were, will be, are not, were not, will not be
Is, was, will be, is not, was not, will not be
Are, were, will be, are not, were not, will not be
Quality
In terms of classes, we can make both the affirmative statement that S is included in P and the negative statement that S is excluded from P. The Affirmative or negative character of a proposition is called it’s quality.
For example, a shadow is a secondary quality. It requires a certain lighting to be applied to an object.
Universal Proposition
A universal proposition is one that contains a universal subject term
“No freshman is a varsity player”. It is a Universal negative proposition but it is making the subject which is “Freshmen” to be for all so Universal applied for this statement.
Particular Proposition
Particular is when it is “some”. Therefore, only partly and not objectively for all.
Some cats like to be cuddled.
Some months’ temperatures are cold.
Singular Proposition
The mark of a singular proposition is that the subject term is a name, pronoun, or phrase standing for a single object. Although in Philosophy we do not want to be objective we then turned to terms to “person”, “people”, “cars”, and “cities”. To make it not targeted.
Quantifier
Words that indicate quantity are called Quantifiers. So far we have considered only the standard ones: “all”, “some”, and “no”. Mean what is the general term.
Contraries
Statement that cannot both be true and cannot both be false.
“all giraffes have long necks” cannot be true at the same time as the corresponding E proposition: “no giraffes have long necks.” Note, however, that corresponding A and E propositions, while contrary, are not contradictory.
Contradictories
If you accept a proposition that “Some bread is not nutritious” then you cannot accept “All Bread is nutritious” because you are going against the two-state argument. If one is true, the other is false, and vice versa. They cannot both be true and they cannot both be false. The proposition that has this relationship is called Contradictories.
Subalternates
It is the opposition between a universal proposition and its corresponding particular proposition. In the corresponding proposition, the universal proposition is called superaltern and the particular proposition is called subaltern.
“If all leopards are mammals, then some leopards are mammals.” When the inference is misapplied, the syllogistic fallacy is called an illicit subalternation.
Subcontraries
When it is impossible for both to be false. Because “some lunches are free” is false, “some lunches are not free” must be true.
Neither can be falsified and therefore it is called a Subcontraries
Existential Import
A statement has an existential import if it implies that something exists. The first statement implies that pizza exists (there IS some pizza somewhere, and it has pepperoni on it).
it is relying on the fact that it does exist inherently or leading on the “if” even if may be true or not.
Converse
You are swapping the Subject and the Predicate. Such as if “No machine are conscious being” to “All machines are non conscious being”
Illicit conversion
Obverse
You take the complement or the non-version. You do the opposite for the Quantity and the Predicate.
Some is not erase you need to remember it. Replacing P and switching quality cancel each other out.
