The reaction may not be completely rational, but it is understandable".

That would be a completely rational trade-off, by the way, but the government won't allow consumers to make it.

In other words, if students are not learning anything, it is completely rational to drop out.

Mouse offers this observation as though it is completely rational.

I am doing this after long and careful consideration; my thinking is completely rational.

"I suppose it should relieve me that in one department, at least, you are not completely rational or objective."

I was not completely rational or objective in more than one department, and Wesley knew this all too well.

But Fearon points out that this is not a completely rational explanation for war.

The fear is completely rational, and the measures may not yet have gone far enough.

We will never know the future (or ourselves) well enough to make a completely rational choice.