The belief which he taught and by which he lived is neither atheistic nor pantheistic; it is not definite enough to be theistic.
"The Roman Poets of the Republic"
W. Y. Sellar
The theistic philosophy which makes the individual the centre of the universe, is, perhaps, nowhere in his works, so distinctly set forth as in this latest of them.
"A Handbook to the Works of Browning (6th ed.)"
Mrs. Sutherland Orr
Accordingly, although the theistic hypothesis would confessedly furnish such an explanation as is lacking, we must not adopt it because we cannot test it experimentally.
"The Old Riddle and the Newest Answer"
John Gerard