Conditional Possibilities vs. Certainties Drill #4

[Basia W]

Good morning,

this question is for the Conditional possibilities and Certainties Drill on page 2-59 Question 4). I am wondering If O occurs, not N Must Be True, given that it is a sufficient condition and required for O to occur (does it have something to do with the negative?)

Thank you for your help!

Very best,

Basia

[David Boyle]

Good morning,

this question is for the Conditional possibilities and Certainties Drill on page 2-59 Question 4). I am wondering If O occurs, not N Must Be True, given that it is a sufficient condition and required for O to occur (does it have something to do with the negative?)

Thank you for your help!

Very best,

Basia

Hello Basia W,

Actually, not-N (or "slash N") is a sufficient condition for O, not a necessary one. The arrow points to the necessary condition, not to the sufficient condition.
So for slash N, O is a necessary condition. Thus, as the answers on p. 2-127 note, N could occur--or it could not occur. This is because neither N nor slash N is necessary for O to occur, from the diagram given.

Hope that helps,
David

[Basia W]

Good evening,

Thank you for your response.
Does this occurrence have to do with the fact that inferring information backwards from a necessary condition means that it is possible that a sufficient condition occurs but not certain?

Very best,

Basia

[KelseyWoods]

Hi Basia!

Yes, you are correct. If you satisfy the necessary condition, it is possible but not certain that the sufficient condition occurs because you are going backwards against your arrow. If you satisfy the sufficient condition, then you move forward along the arrow and you can be certain that the necessary condition occurs.

Hope this helps!

Best,
Kelsey