There's you...and there's others.
You can know by noting the famous and well-respected...and you may know by co-relating with those whose words speak to you. Your consciousness is where you are, and deepening it with active reading of like minds is one option; developing new thoughts is another; in both cases, your living awareness is where you are, and the level you best function at, presently.
Being aware of your own preferred process of evaluation--if any pattern is detectable--may be helpful: do you tend to retain childhood likes, or perhaps you are more of an explorer, now. Do you prefer known, favorite cuisine, or trying unknown dishes, or a combination of the two polarities, etc.
As one Bard of Ireland, Thomas Moore, wrote, about his home, his wisdom may be applied to reading any given author as a constructor of a house of consciousness.
"That dear home, that saving ark,
Where love's true light at last I've found,
Cheering within when all grows dark,
And comfortless, and stormy around."
p.s. You probably note that Gurdjieff was a Son of God, who had the Christ Mind which was also in Saint Paul, Saint John, and others, regardless of their imperfections.