It's not unreasonable to want to know why the company is hiring for this job. One way to find out is to ask, "Is this a new position?" If the answer is yes, that opens the way for more questions and discussion. You'll want to know why the position is being created. Does it involve a new initiative? Is an existing position being duplicated or divided? Who has defined the job and its responsibilities? How will success be measured, if there's no precedent?
A "no" answer also raises more questions. Why did the previous person in the job leave? How long do people typically stay in this job? Are there usually chances for advancement?
Some other good questions also tend to raise more questions. Read on.