Expressing Manner

Traditional grammar distinguishes adverbs by establishing semantic classes: adverbs of place are the starting point of this classification, followed by adverbs of time and manner adverbs. But what is manner? Unlike space or time, it has never been the subject of in-depth investigation. We take for granted that it is an ontological category, which the question "how" detects, but what else can be said about this concept? Where does manner originate? How is it encoded linguistically, especially in adverbless languages? Given that the question "how" can also cover such heterogeneous notions as degree, instrument, etc., is manner an elusive concept or can it be precisely defined?