Here is a journal entry from henry david thoreau that demonstrates how he thinks the word philosophy should be used:
“Philosophy is a Greek word by good rights, and it stands almost for a Greek thing. Yet some rumor of it has reached the commonest mind. M. Miles, who came to collect his wood bill today, said, when I objected to the small size of his wood, that it was necessary to split wood fine in order to cure it well, that he had found that wood that was more than four inches in diameter would not dry, and moreover a good deal depended on the manner in which it was corded up in the woods. He piled his high and tightly. If this were not well done the stakes would spread and the wood lie loosely, and so the rain and snow find their way into it. And he added, “I have handled a good deal of wood, and I think that I understand the philosophy of it.”
(Journal, December 15, 1859)
This is an example of Lenient use of “philosophy”.
References
Thoreau, H. D., & Stilgoe, J. R. (2009). The Journal of Henry David Thoreau, 1837-1861 (D. Searls, Ed.; Illustrated edition). NYRB Classics.