Being Logical

A science is any organized body of knowledge that is possessed of first principles. The first principles of any science are those fundamental truths upon which the science is founded and by which all its activities are informed.

It is important to be aware of the difference between truth and validity. Though often confused, they are in fact quite different. First, truth has to do only with statements, whereas validity has to do only with that structural arrangement of statements that we call an argument. Second, a statement is true if what it asserts reflects what is objec

Aristotle’s pithy two-word definition of man—the rational animal—has gained classical status. “Animal” is the proximate genus; “rational” is the specific difference.

Facts can also be thought of as objective or subjective. Both things and events are objective facts. They exist in the public domain and are in principle accessible to all. A subjective fact is one that is limited to the subject experiencing it. A headache would be an example of a subjective fact.

There are two basic types of objective facts, things and events. A “thing” is an actually existing entity, animal, vegetable, or mineral. The White House is an example of the first type of fact, and the assassination of Abraham Lincoln of the second. The first type is more basic than the second because events are made up of things or of the actions

The affirmative statement is more direct and emphatic. (This is true of all affirmative statements.) Because its emphasis is on what is the case rather than on what is not the case, it elicits a positive response.

Don’t treat evaluative statements as if they were statements of objective fact.

I establish a fact if I successfully ascertain that there is, for a particular idea I have in mind, a corresponding reality external to my mind. For instance, I have a particular idea in my mind, which I label “cat.” Corresponding to that idea are actually existing things in the extramental world called “cats.” But I could have another idea in my m

An ambiguous term (“equivocal,” in the language of logic) is one which has more than a single meaning and whose context does not clearly indicate which meaning is intended.