Actually this is a bloody good question
.And what IS Holy Spirit ? O.K. I`ve seen the definitions in the dictionary but when you boil it all down its just an imaginary concept.Their is no definitive proof of such a thing/state that exists in all the time/ages that humans have existed and no tangible evidence that such a thing ever existed.
So if such a thing as the Holy Spirit never existed you could neither be inspired or directed or be guided by such a thing as the Holy spirit.
Those that believe in the Holy Spirit do so because of Faith and that is not a good basis for believing in anything .
Billions of people over the Centuries have been misled by believing in "Faith" of one sort or another .