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# Fundamentals: Truth and Validity

In this video, Julianne Chung explains the philosophical concepts of truth and validity before going on to illustrate how truth and falsity, as well as validity and invalidity, can appear in various combinations in an argument. She then introduces the concept of a sound argument (i.e., a valid argument whose premises are all true) and presents one reason to think that valid arguments with false premises are also of interest.  For more detailed discussions of validity and soundness, please be sure to have a look at the videos on these topics by Paul Henne (Duke University) and Aaron Ancell (Duke University), respectively.

Speaker: Julianne Chung, Yale University.

## Want to join the conversation?

• The video is called "Fundamentals: Truth and Validity" and is great in terms of explaining Validity, but I think it is lacking of quality when speaking about what is "Truth"; Is truth about a probability function? Is truth a relative concept? It is a consensus?
The examples sound great on paper, but how is it possible to identify the true premises in real life?; I mean, these examples are very obvious, but when it comes to deal with real problems and real situations, you almost never know if the premises are false. What is necessary to do in this situations?
• I'll tell what I know. It's not much but I hope it helps.
There are 3 types of statements:
1. Empirical statements that report what people observe through their senses e.g. Grass is green. To verify such statements, you have to make an observation or rely on someone's testimony. You could go out, look at grass and if it is green, you can say "Grass is green" is true. Another way, if observation is not possible, is to take somebody's word for it - testimonials. To accept a testimonial empirical statement, the person making the claim must be (1) reliable-the person must not be liar and (2) the claim must be plausible-it should fit with the existing framework of knowledge.
2. Definitional statements report about how a word is used e.g. A square is a rectangle with all sides equal. To verify such statements, you only need a dictionary.
3. Statements by experts. To verify such statements, the 'expert' in question must fulfill the following criteria
a. Appropriate credentials (degrees, publications, position, etc)
b. Appropriate area of expertise (a physicist's statement on zoology should be doubted)
c. Reliability (the expert should not have lied in the past)
d. Expert consensus (if there is disagreement among the experts, you should doubt the statement)
e. Lack of bias (does the expert have a reason to lie? financial benefit? political or ideological bias)
• It has been shown how a deductive argument should be for it to be valid, but when the argument is not deductive? How do we evaluate the validity of an inductive argument, for example?
• why should the observation that Jon is bowling cast more doubt on premise 1 (he's sick) than premise 2 (if sick, won't bowl)?
(1 vote)
• If Jon's boss sees him bowling, then that instantly makes premise 1 false. The second premise stated that IF Jon was in bed with the flu, then he is not bowling. So if Jon is not in bed with the flu, there is a chance that he will go bowling. The fact that whether he is sick in bed or not does not determine the truth or falsity of the premise. You have to consider the "if" part of the premise. If the premise just stated that Jon was not bowling, then it would be false. I hope this helps!