What is circular about the Holy Spirit, or trusting Him to do what Jesus promised He would do?
It is circular because of the many claims of guidance by the Holy Spirit which has resulted in a myriad of interpretations of Scripture, the nature of Jesus, the nature of faith and the nature of salvation and how one is saved.
To claim only the inspiration of the Holy Spirit as having revealed truth, is to make a claim that one cannot back up with anything, even Scripture since so there is so much discordance within the interpretation of the simplest Bible verses.
IOW, some say Scripture alone, some say predestination, some tout the Rapture and Tribulation, others dispute it, so with the very same Scripture the case is made by a myriad and very differing number of sects for their truth, all claiming inspiration by the Holy Spirit as their proof.
Is it the Holy Spirit which is schizophrenic then?