Formal Logic Systems

Logic

the organized body of knowledge or science that evaluates arguments

Argument

a group of statements, one or more of which (the premises) are claimed to provide support for, or reasons to believe, one of the others (the conclusion)

Statement

a sentence thats true or false (a declarative sentence)

Truth value

the truth or falsity of a statement

premises

the statements that set forth the reasons or evidence

conclusion

the statement that the evidence is claimed to support or imply

conclusion indicators

therefore, wherefore, thus, consequentyl, we may infer, accordingly, we may conclude, it must be thaat, for this reason, so, entails that, hence, it follows that, implies that, as a result

premise indicators

since, as indicated by, because, for, in that, may be inferred from, as, given that, seeing that, for the reason that, inasmuch as, owing to

inference

the reasoning process expressed by an argument (interchangeable with argument)

proposition

the meaning or information content of a statement (interchangeable with statement)

syllogistic logic

a kind of logic that fundamental elements are terms, and arguements are evaluated as good or bad depending on how the terms are arranged in the argument

modal logic

a kind of logic that involves such concepts as possibility, necessity, belief, and doubt

Warning

a form of expression that is intended to put someone on guard against a dangerous or detrimental situation (“watch out that you dont slip on the ice”) no evidence its true = no argument

piece of advice

form of expression that makes a recommendation about some future decision or course of conduct (similar to warnings)

a statement of belief or opinion

is an expression about what someone happens to believe or think about something (no argument)

loosely associated statements

about the same general subject, but they lack a claim that one of them is proved by the others (no argument)

report

consists of a group of statements that convey information about some topic or event

expository passage

a kind of discourse that begins with a topic sentence followed by one or more sentences that develop the topic sentence (if used to elaborate = no argument)

illustration

an expression involving one or more examples thats intended to show what something means or how it is done (no argument but misleading)

arguments from example

illustrations taken/interpreted as arguments

explanation

an expression that purports to shed light on some event or phenomenon

If it rains, the ground gets wet. It rained. Therefore, the ground is wet. What does this illustrate?

Modus Ponens

If a person is a bachelor, he is unmarried. John is married, so he is not a bachelor. What does this illustrate?

Modus Tollens

Which is invalid?

Modus ponens/tollens, affirming the consequent, or denying the consequent?

Affirming the consequent

If the lamp is plugged in, then it will turn on. The lamp does not turn on. Therefore, is it not plugged in. What does this illustrate?

Modus tollens

Deductive reasoning aims for conclusions that are:

Necessarily true if premises are true

Inductive reasoning aims for conclusions that are:

Probably true given premises

Every swan I’ve seen is white. Therefore, all swans are white. This illustrates?

Inductive

All humans are mortal. Socrates is a human. Therefore, Socrates is mortal. This illustrates?

Deductive

Which type of reasoning is tested for validity?

Defuctive

An argument is valid if:

It’s conclusion follows logically from premises

An argument is sound if:

It is valid and all premises ar