Self-paced
I just took PT 148 Section 1 and I'm very confused with question 21. It reads:
No occupation should be subject to a licensing requirement unless incompetence in the performance of tasks normally carried out within that occupation poses a plausible threat to human health or safety.
'No' is a negated necessary indicator & 'unless' is a negated sufficient indicator. The curriculum says when encountering these it doesn't matter if you put the term as the necessary or sufficient condition because of the contrapositive. But, when you have both indicators that surely can't be the case as this question proves. If the curriculm covers how to handle conditional statement with both kinds of indicators I missed it.
So my question is, how do you handle these? Do you just need to use intuition to figure out which term goes in the sufficient/necessary spots? Do you prioritize one indicator over the other? Or do the indicators cancel each other out and you proceed as if they never existed?
The diagram for this questions is
If subject to licensing agreement (LR) → Incompetence poses threat (IPT)
(Contra) /IPT → /LR
1
4 comments
Follow the rule for unless. Treat the "no" as a negation of the concept it's connected to:
No X unless Y.
The two parts: [No X] and [Y]
You negate one of those parts, make it the sufficient condition.
If NOT Y --> NO X
or
If X --> Y
So your diagram is correct -- it looks like you intuitively applied the unless rule in the way I described above.
@Kevin_Lin Thanks so much for your reply Kevin! I really appreciate your teaching approach.
Can it be said, as a general rule, that if a statement has both group 3 & 4 indicators that you follow the rule for group 3 and negate the term associated with group 4?
The confusion for me here is that negating the term associated with 'No' doesn't work in statements where there is no group 3 indicator. For example:
[No cats] are [dogs]
It's not true that (/Cat → Dog). To find the true translation we follow the group 4 rule, negate necessary and place either term there. (Cat→/Dog) or (Dog→/Cat).
I guess what I'm trying to get at most is that I'm not sure why we must change up the rules regarding the placement of the sufficient & necessary conditions in these 2 situations. Thanks to your explanation though I now understand how to translate statements with 'No' & 'Unless'.
@JoshuaA1100 I'm not sure I'd be able to explain grammatically what's happening; if it helps, you actually can apply the "no" rule to "No X unless Y," it's just that the "unless" would then be treated as a negation. "Unless" essentially means "if not":
"No X if not Y"
NOT Y --> NOT X
X --> Y
You can apply the "no" rule if you want, but it just gets awkward:
If X --> NOT [not Y]
If X --> Y
I don't think the "no" is changing in how it operates in any of these sentences; what's changing is the easiest way for us to understand the sentence. Even "No cats are dogs" could be interpreted with "no" as a negation, as long as you reword it like this:
"No cat IF dog" = Dog --> Not cat
@Kevin_Lin Thank you, these explanations are super helpful! Reading the 'unless' as 'if not' makes a lot of sense and helps me keep track of the conditionals :)