"…had naturally begotten in me a power of concentration beyond the average. My hour of mental prayer every morning and another hour every evening for nearly a quarter of a century had given me a facility in quieting the life of the senses of the discursive mind, and a capacity for fixing my attention with a quiet steady regard on the subject of consideration. (=shamata imo, not his term)
…I brooded over the mystery of life, not trying to solve it, but striving to lose myself in its depth, allowing its inexplicableness to flow over me.
This was the effect of my contemplation upon me. A new faculty of knowing seemed to be born in me, in the quiet stillness yet intense activity of consciousness within me. I seemed to touch the heart of reality, the very essence of existence, with a directness, an immediacy, rendering all my former knowledge false and illusory. As it were, I seemed to sense another dimension; or perhaps I should express it better were I to say that all dimensions seemed to go, leaving me conscious of presence, a reality having no form that the senses could comprehend, yet not abstract and lifeless, as were the ideas of the mind, but concrete, vital, palpitating with realness."
It is fascinating to read a description of śamathā and mahāmudra/dzogchen meditation independent of Buddhist terms and concepts. It provides yet another perspective, and is invaluable for that reason.
It brings home the fact that this is a natural, spontaneous, and universal experience, and not a fabrication based on a particular culture or tradition.