Let's say PERSON A has a patent idea for a new type of golf club... and in their patent application, they say the reason for the invention is that golfers need a better tool to do x,y, and z to help their golf game. They are granted the patent.
But let's say it turns out that this new golf club actually makes a really good cooking utensil as well... and ends up up being used for that purpose more than for the "intended" purpose.
Then PERSON B sees this and comes along and applies for a "new" patent for the exact same basic object, but claims that it is expected to be used as a cooking utensil and therefore doesn't infringe on the prior patent by person A.
Let's say then for the sake of argument that person B is granted the patent also.
Then let's say PERSON C has a completely unrelated invention... but having learned from what happened with persons A and B... they decide not to claim any specific purpose for their invention.
I guess what I'm asking is... is it necessary to specify the expected domain of usage for an invention... or can one simply only say... "it is an object with certain properties and behaviors."