Arguments are never true or false.  Only premises, conclusions, declarative and/or exclamatory statements, propositions (in ordinary language, sentences) are true or false.
      Inductive arguments are based on empirical data (in ordinary language: experience of the real, i.e., physical) world.
      They are good, bad, weak, or strong (not valid, invalid, sound, true, or false).
      Their conclusions are only PROBABLE, never necessary, and include new information that does not appear in the premises.
      That is the case because it is only probable that all the necessary premises are included or that the premises are descriptively true.
      Evidence, facts, knowledge, etc., are always OPEN-ENDED.
      The evidence is never all in.
Deductive arguments may be valid, invalid, sound, or unsound.
     If valid, they are NOT necessarily sound; i.e., the premises and conclusions need not be true, but the conclusion is NECESSARY.
     There is NEVER (new) information in the conclusion that is not already stated (often hidden) in the premises.
     The premises and/or conclusion may be true or false.
     If false, the arguments are valid but unsound.
     Ex: 1. False premises, therefore, false conclusion:  (If) cats are pianos, (and if) pianos are dogs, (then) cats are dogs.
     Ex: 2. True premises, therefore, true conclusion:  (If) children are human beings, (and if) human beings are mortal, (then) children are mortal.
     Notice the form:  Let cats and children = C.
     Let pianos and human beings = P.
     Let dogs and mortal = D.
     In both examples the result is: (If) C is P and (if) P is D, (then) C is D.  This is proper form and BOTH arguments are VALID.  But only ex. 2 is SOUND.
When the premises are true, the conclusion must (NECESSARILY) be true.
     Whether the conclusion and/or the premises are true or false.
     Ex: 1. (If) all children are human, (and if) all people are human, (then) all children are people.
     Ex. 2. (If) all children are human (and if) all men are human, (then) all children are men.
     Notice the form: In both examples, let children = A.
     In both examples, let human = B.
     In both examples, let people and men = C.
     We then have (If) A is B, and (if) C is B, (then) A is C.  This is an improper form and therefore BOTH arguments are INVALID.  For an argument to be SOUND, it must first be VALID.
     In Example 1 the premises and the conclusion are true, but in example 2 the premises are true and the conclusion is false.
     In example 1 the conclusion is true by accident, but nevertheless is an INVALID argument because it is not NECESSARILY true.
The premises and the conclusion must be true.
     Sound arguments are also valid arguments.
     In sound arguments the premises are true and the conclusions are necessary; i.e., they necessarily follow from the premises, and are necessarily true.
     Ex: (if) all children are human beings, (and if) all human beings are mortal, (then) all children are mortal.
     Verbal disagreements are caused by differences in meanings of a word and/or by discussing different issues without recognizing that they are different.
     Ex: There is sound in the desert when an atomic bomb "goes off."
     TRUE, if "sound" means "sound waves--vibrating air.
     FALSE, if "sound" means "experiencing the noise" and there are no living entities there to perceive (hear) it.
     An honest disagreement about the truth-value of a statement.
     Ex: Taxes should be raised. Yes.  No.


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© 1997 by Pasqual S. Schievella