#18- Columnist: Taking a strong position on an

[Capetowner]

"If only" is a necessary indicator. Why is "To ensure" in B a sufficient indicator? So confused how sufficient/necessary indicator combos like this can go either way

[Luke Haqq]

Hi Capetowner!

If you're faced with a sentence that seems to contain conditional reasoning but it doesn't seem clear how to diagram it out, you could try re-formulating what you're reading into simpler, different language, which could potentially add clarity as to how to diagram the original statement. For example, how would you diagram something like the following: "To ensure you don't get rained on outside, you should bring an umbrella"?

[Capetowner]

Hi Capetowner!

If you're faced with a sentence that seems to contain conditional reasoning but it doesn't seem clear how to diagram it out, you could try re-formulating what you're reading into simpler, different language, which could potentially add clarity as to how to diagram the original statement. For example, how would you diagram something like the following: "To ensure you don't get rained on outside, you should bring an umbrella"?

Bring umbrella ----> Don't get rained on
Is this correct?

[Jeff Wren]

Hi Capetowner,

To follow up on your previous question, "to ensure" means "to make certain that (something) shall occur or be the case." In other words, "to ensure" means "to guarantee that something will happen." This matches the idea of sufficiency because the sufficient condition guarantees that the necessary condition happens, but not the other way around.

The tricky part is understanding what term in the sentence does ensure/guarantee the other term versus what term is being ensured/guaranteed. For example, in the construction of the sentence, "To ensure that A doesn't happen, do B," it is B that ensures that A doesn't happen. The word "that" indicates that A is what gets ensured/guaranteed, rather than what does the ensuring/guaranteeing.

However, in the sentence, "A ensures B" A would be the sufficient condition because it is the term ensuring/guaranteeing that B happens.

As for Luke's example,

"To ensure [that] you don't get rained on outside, you should bring an umbrella."

The thing that ensures/guarantees that you don't get rained on is "bringing an umbrella," so that term is the sufficient condition.

In other words, the sentence could be rewritten:

"You should bring an umbrella to ensure (i.e. guarantee) that you don't get rained on outside."

For that reason, your diagram:

Bring umbrella ----> Don't get rained on

is correct.