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# "Since" necessary or sufficient condition?

Alum Member
in General 374 karma
I know this is probably a rookie question, but I require an expert answer. So how do we diagram since? I don't recall it in the lessons. I have reasoned it myself so I'll give my input first and tell me if I'm wrong.

Since it's Raining, the soccer game is Cancelled
R --> C (if it's raining, then the game is cancelled)

It cannot be drawn as C --> R. (if the game is cancelled, how can we assume it was cancelled because of the rain? Maybe there was a terror plot or an earthquake)
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• #### Sufficient condition vs necessary conditionI understand that necessary condition has to be 100% true while sufficient is more of a "good enough" explanation for if something else is true. But …

• Free Trial Inactive Sage Inactive ⭐
2398 karma
Hey Sarkisp!

In general, since indicates a premise (as opposed to a conclusion) and shouldn't be regarded as an indicator of sufficiency. In the above relationship, it's probably not appropriate to diagram as if it were conditional language because what you describe is a one-time cause and effect relationship (because it rained, the game is canceled). If you were to diagram it as you did above (R-->C) it would mean that any and every time is rains, it must be true that the soccer game will be canceled, which is slightly different logically from the initial relationship you described.

If the relationship was "the game was cancelled tonight, since when it rains, all games are canceled," then it would be appropriate to diagram as "R-->C". Notice here that "since" indicates that the premise follows and what comes before since is the conclusion (the game was canceled).

You are correct in saying that R-->C is not the same logically as C-->R because the necessary condition, C, can stand alone independent of the sufficient. So yes, just because the game is canceled doesn't mean it rained; the game could have been canceled because all of the team members on both teams decided to go watch the Republican Debate instead.
• Alum Member
180 karma
"Since" is a premise indicator (which functions a lot like "for", the conclusion can go on either side of the since/for clause).

I would caution against trying to jam "since" or any other premise indicator into a conditional relationship. We don't have evidence without conditional language that this situation takes place in every case.
• Alum Member
edited September 2015 374 karma
Okay thanks for that @c.janson35 and @LoraxMan

I was noticing it in some MBT and SA questions with conditional language and thought there was a way to diagram always. But I see what you are both saying now. So in those types of questions, if I see since, then basically just do the following:

For example, an SA type question:

X --> T
C (this one is the since; it wouldn't connect to the other two conditionally but rather in the form here as a premise)

Then let's say the conclusion is D. Without getting overly specific I know how to do SA's but basically just find the answer choice that then connects the "since C" conditionally to the rest?
• Free Trial Inactive Sage Inactive ⭐
2398 karma
A SA question would more likely take the form of:

X--->T
T
----------
D

(Which might be written as "since T, we know D")

In which case the SA would have to connect the variables T and D. This would look like this: "T-->D". And since we know T, the conclusion would be 100% valid.
• Alum Member
180 karma
@sarkisp23 what question are you referencing? It would certainly help my knowledge if you could share. Thanks!
• Member
edited June 2017 7 karma

Just wanted to say I came here with almost the same question- only the word I was wondering about was "because". (More specifically, how it is used in PT37,sec2,q12, answer E). After reading comments here, I assume "because" should be treated the same way as "since" (as they prettymuch mean the same thing).
However, I suspect that premise indicators like "since" or "because" can be used WITH necessary/sufficient indicators, which can confuse people, such as in the case of the question I cited above where the combination ["when" X... "because" Y] is used. Maybe an expert can back me up on that but hopefully it helps.

• Yearly + Live Member Sage 7Sage Tutor
10801 karma

@"Mr.Tinklebottom" said:
Just wanted to say I came here with almost the same question- only the word I was wondering about was "because". (More specifically, how it is used in PT37,sec2,q12, answer E). After reading comments here, I assume "because" should be treated the same way as "since" (as they prettymuch mean the same thing).
However, I suspect that premise indicators like "since" or "because" can be used WITH necessary/sufficient indicators, which can confuse people, such as in the case of the question I cited above where the combination ["when" X... "because" Y] is used. Maybe an expert can back me up on that but hopefully it helps.

Because, like you suspect, is definitely a premise indicator. Because can be translated as "for the reason that" which signifies support for a statement.

For combination statements, because would signify the start of a support statement.
For example: Because when X then Y. Therefore, when X then Z.
*because signifies support for the conclusion - mainly one conditional statement, X--->Y, for the other conditional statement, X--->Z.
In this instance if its a necessary/sufficient assumption or strengthening question the right answer might look like Y-->Z.

I hope this helped. : )