Apologies in case this has been previously covered (there's quite a few comments on this thread and I haven't seen this).
Rule 2 for making a valid deduction is that they must have the Sufficient in common.
In example 3, we set out A-some-B and B --> C. It is then explained that the sufficient in this example is "in common".
However, the first exercise on the next page is W-some-U and W --> V, where it is also noted that the sufficient is "in common".
What am I missing - how can the sufficient be in common for each of these?
Replies
Create a free account to read and
take part in forum discussions.
The term "sufficient condition" is referring only to the variable's role in the S->N statement, not in the quantifier statement.
In the first example you mentioned, we have the S->N statement "B->C." Here, B is the sufficient condition and C is the necessary condition. The some statement "A-some-B" also has the variable B, which we identified as the sufficient condition, so we can say they have the sufficient condition in common and connect the two statements with the arrow pointing away from the quantifier.
In the second example you mentioned, we have the S->N statement "W->V," where W is the sufficient condition and V is the necessary condition. The some statement "W-some-U" has W, which we identified as the sufficient condition, so we can say they have the sufficient condition in common and connect the two statements with the arrow pointing away from the quantifier.
Does that make sense? Please let us know if you have any other questions!
