Lesson 2, Page 59 Conditional possibilities drill, #3

[hanvan]

Hello, I am doing the drill on page 2-59 , question 3, virtual class. I think if H does not occur, J does not not occur either, because the statement shows that " H OR J" are sufficient , when we switch to necessary they have to become " H AND J", and neither of them occur, then why the answer said :" J does not occur and J could occur " are in the category ( could be true). I think :" J does not occur" should be in must be true category, and "J occurs" should be in the " can not be true" category!
Please explain, and thanks in advance!!

[Steve Stein]

Thanks for your question. I think the conditional concept you're asking about can be more easily understood with an example:

Who will attend the party? If either Henry or James attends, then Kevin will attend, and if Kevin attends Larry will attend.

Henry
or Kevin Larry
James

The presence of either Henry or James will bring Kevin. If Henry doesn't attend, though, James still has the choice.

Let me know whether that clears this one up--thanks!

~Steve

[hanvan]

I see it now. Thanks Steve!