The Holy Spirit

Right now I'm reading for my Introduction to Philosophy class. The book is The Passion of the Western Mind by Richard Tarnas. Tarnas communicates abstract thoughts and difficult material very effectively and simply. Anyway, I'm in section three: The Christian Worldview. It's a history of the beginnings of Christianity and its evolution. This man is clearly not a believer and it is sad to see how he misunderstands Scripture and even the history of the Church. Take this passage on the Holy Spirit:

The notion of the Holy Spirit as a divine principle of revolutionary spiritual power, immanent in the human community and moving it toward deification, diminished in Christian belief in favor of a notion of the Holy Spirit as solely invested in the authority and activities of the institutional Church.

I guess this illustrates the absolute need for faith, "but without faith is is impossible to please him, for he who comes to God must believe that he is, and that he is a rewarder of those who diligently seek him" (Hebrews 11:6). Without belief, human reason cannot come to grips with the Almighty God and his exclusive plan of salvation.