Based on the passage, it can be concluded that the author and Broyles-González hold essentially the same attitude toward

Ryan on March 14, 2019

Rules for Making Valid Deducations

So for rule #2 "Must have S condition in common" this means that it just has to be a sufficient condition in one of the S&N conditions? It does not have to be the sufficient in both conditions, correct?


Jacob on March 15, 2019

I assume you are discussing Rule 2 at approximately minute 29 of the lecture.

One of the premises in each of these examples is a “some” statement. The other premise is the sufficient/necessary statement. The sufficient condition must be in common in both premises. For example, in Example 4, Z is what is in common of both premises, but Z is the necessary condition in the sufficient/necessary statement — and so there is no valid inference.

Ryan on March 17, 2019

Thank you!