Sufficiency and Necessity in Conditional Statements Forum

[WeightliftingThinker]

Is the sufficient condition always after the "If" and the necessary condition always after the "then?"

[ponderingmeerkat]

Is the sufficient condition always after the "If" and the necessary condition always after the "then?"

If a statement is formatted in the "if-then" format, then the "if" phrase denotes the sufficient condition and the "then" phrase denotes the necessary condition. (See what I did there...)

You will never see "if" denote a necessary condition because, by definition, necessary conditions MUST happen if the sufficient condition is met (see again, what I did there...)

[Phil Brooks]

Is the sufficient condition always after the "If" and the necessary condition always after the "then?"

If a statement is formatted in the "if-then" format, then the "if" phrase denotes the sufficient condition and the "then" phrase denotes the necessary condition. (See what I did there...)

You will never see "if" denote a necessary condition because, by definition, necessary conditions MUST happen if the sufficient condition is met (see again, what I did there...)

This is wrong. "Only if" precedes a necessary condition.

Stop thinking formulaically and looking for magic words like "if". That is a recipe for falling for the tricks the test-writers will put on there. Instead, remember the conceptual distinction: a necessary condition is something that MUST happen (so anything denoting necessity--"only if", "must", "had to", "provided that", "on the condition that" etc.), while a sufficient condition is something that, if known, automatically tells you something else ("All boys are tall", "if x then y", "once you go here, I will go there", etc.).

[ponderingmeerkat]

Is the sufficient condition always after the "If" and the necessary condition always after the "then?"

If a statement is formatted in the "if-then" format, then the "if" phrase denotes the sufficient condition and the "then" phrase denotes the necessary condition. (See what I did there...)

You will never see "if" denote a necessary condition because, by definition, necessary conditions MUST happen if the sufficient condition is met (see again, what I did there...)

This is wrong. "Only if" precedes a necessary condition.

Stop thinking formulaically and looking for magic words like "if". That is a recipe for falling for the tricks the test-writers will put on there. Instead, remember the conceptual distinction: a necessary condition is something that MUST happen (so anything denoting necessity--"only if", "must", "had to", "provided that", "on the condition that" etc.), while a sufficient condition is something that, if known, automatically tells you something else ("All boys are tall", "if x then y", "once you go here, I will go there", etc.).

Good feedback. "Only if" denotes a necessary condition. "If" denotes a sufficient condition.