If they did know there would not be all those different theories.

Now, I realize that some of you have a different theory on how to grow the economy.

There are a few different theories as to why and how children develop language.

There are several different theories regarding the name of the community.

The way it works is a theory (actually several different theories).

There's a different theory about what really happened that night.

Players offer different theories why the Yankees began playing better.

There are several different theories about the meaning of the mountain's name.

Everyone has a different theory about what is going on in the company that so dominates this town.

There are many different theories as to its origin and history.