Oz Fritz's entire post on Musical Gnosis and Philip K. Dick is worth a careful read, but I particularly liked this passage on Gnostic agnosticism:
Taking a gnostic approach to agnosticism indicates a willingness to experientially seek out the truth of deeper philosophical matters, like 'Who am I' and 'Why am I here' despite never reaching a final conclusion. A good example of this in play occurred at a RAW Q&A session when I asked Wilson what he thought about the Secret Chiefs. In the Thelemic system, the Secret Chiefs represent the enlightened masters who supposedly guide human destiny. They have corollaries in other occult systems such as Theosophy. "The Secret Chiefs," RAW replied, "are a useful metaphor."
I suspect that "Gnostic agnosticism" also could be a way to describe the attitude of Robert Shea. His zine No Governor No. 7 (available from the "Resources" links at this site) includes a newspaper article about him from the "Glencoe News" newspaper, Jan. 3, 1985. It quotes Shea as saying that he had been interested in mysticism for years and meditates for 20 minutes a day.
"I got involved in mysticism thinking it would give me some practical benefit," Shea says in the article. "But once you get into it, you lose that motivation. Writing becomes a way of getting closer to mysticism."