Conditional Reasoning

[rbolin]

Using LR Flashcard #127

Conditional Reasoning

T or F?

If there is a conditional relationship between two events, the sufficient event is always understood to take place before the necessary event.

False!

There is no implied temporal relationship between a sufficient and necessary event.

I understand all this until the example.

For example, "We can only win this battle if we receive more supplies" would be diagrammed as:

Win --> Supplies,

even though the victory would clearly take place after the receipt of more supplies.

Again, I understand the temporal point being made. What I am confused on is the Indicator words and the diagram. I would have diagrammed the statement as:

"if" Supplies --> "only" Win

Can someone please explain this. Thanks!

[Steve Stein]

Hi rbolin,

I hope you are finding our flashcards helpful. Thats a good question you've asked, and something of a tricky example.

The challenge with this example is in the wording, and the position of the term "only." Keep in mind, however, that we could reword the example as "we will win the war only if we receive more supplies."

That's why we need to consider the logic of the relationship between those two conditions. Let's say the war has now ended, and we won! what else do we know? we must have gotten supplies we needed (win war got supplies)

If we hadn't received supplies, there's no way we could have won--and that's the contrapositive (didn't get supplies didn't win the war)

Once again, what is the necessary condition in this example? What needs to happen? If we are to win the war, we need to get more supplies. (win war supplies)

Good question! Conditional reasoning can be very challenging--please let me know whether this is clear--thanks!

~Steve

[rbolin]

This helps. Thanks Steve.