Conditional Statements with Both Group 3 and 4 Indicators

Nikkkkkkk

Hey all. I'm just wondering how most people deal with statements with both Group 3 and Group 4 indicators. I realize that one can use either rule and be fine, but in practice do most people just stick with one rule? I find it makes more intuitive sense to use the Group 3 rule, and was wondering if there were any downsides to just sticking with using the Group 3 rule at all times when I encounter a statement with both indicators.

For example, in the following statement:

"There will not be a good show unless there are sophisticated listeners in the audience."

With the Group 3 rule, one would diagram as:
GS --> SL

because one is negating the sufficient (/GS), which turns it into GS. The fact that "not a good show" is /GS makes intuitive sense to me because not should mean /.

However with the Group 4 rule:
not a good show becomes GS
unless there are sophisticated listeners becomes /SL
and therefore

GS --> SL

because one is negating the necessary (/SL) and making the other idea (GS) the sufficient condition. However, this is where I always get tripped up, because I don't think it makes intuitive sense for unless to be a negation. Also, my mind makes me constantly think that "not a good show" has to mean /GS, so leaving it as GS is really difficult for me to intuitively grasp.

What do others think? Is it fine if I just stick with the Group 3 rule for every statement that has both indicators? Are there any cases where using the Group 4 rule would be better?

Alex

@Csuposki said:
Hey all. I'm just wondering how most people deal with statements with both Group 3 and Group 4 indicators. I realize that one can use either rule and be fine, but in practice do most people just stick with one rule? I find it makes more intuitive sense to use the Group 3 rule, and was wondering if there were any downsides to just sticking with using the Group 3 rule at all times when I encounter a statement with both indicators.

For example, in the following statement:

"There will not be a good show unless there are sophisticated listeners in the audience."

With the Group 3 rule, one would diagram as:
GS --> SL

because one is negating the sufficient (/GS), which turns it into GS. The fact that "not a good show" is /GS makes intuitive sense to me because not should mean /.

However with the Group 4 rule:
not a good show becomes GS
unless there are sophisticated listeners becomes /SL
and therefore

GS --> SL

because one is negating the necessary (/SL) and making the other idea (GS) the sufficient condition. However, this is where I always get tripped up, because I don't think it makes intuitive sense for unless to be a negation. Also, my mind makes me constantly think that "not a good show" has to mean /GS, so leaving it as GS is really difficult for me to intuitively grasp.

What do others think? Is it fine if I just stick with the Group 3 rule for every statement that has both indicators? Are there any cases where using the Group 4 rule would be better?

I think as you can already see it comes down to preference and what makes more sense for you intuitively. I don't stick to any hard and fast rules when it comes to which group to use, I just translate the sentence into logic which whatever feels "right." And often what feels right is determined by how the sentence is written. I think I adopted this way because it seems to be how JY does it, as I've seen him use both group 3 and group 4 when encountering a sentence with both indicators.

Freddy_D

As long as you are translating it correctly, I don't think it really matters. I am more group 3 person as well because I like to get the rule-induced negation out of the way first.

NotMyName

Personally, when a sentence contains "unless" I almost always find the negate-sufficient more intuitive because it seems to require very little alteration.