"By logic, they should green- light this deal, but who knows what political issues will get involved."

And by logic, this thing speaking to us is some higher power.

I guess the actual figure by your logic then is 25,000.

What they mean is that you can prove anything by bad logic.

I know not by what logic you must so conclude.

"But you know he's not going to be able to solve this problem by logic."

When people say that you can prove anything by logic, they are not using words in a fair sense.

By his logic, Apple would have been just as good for its users if the tax was 60%.

By your logic, you may end up with no Compuserve.

By your own logic, my idea is a good one.