Etymology of ～かもしれません

Question

So, today one of the topics boarded in the lessons I'm taking was the form

～かもしりません

Now, I'm thinking the しれません part comes from the potential form of 知る. That way, in the sentence, it would mean something like "can't know", giving the "guessing" property of the form.

Could someone confirm if this train of thought is correct? Also, I haven't found a meaning for the かも bit, so I would appreciate one if possible.

Answer 1

I would think that しれません comes from the verb 知れる which means "to be known" rather than "to know".

The か part forms an embedded question e.g.

何時に始まるか調べてください。
What times does it begin? Please check.
Please check what time it begins.

も is a tricky particle. I'm going to claim that it means 'even' in this context, but I think it is more subtle.

Putting it together we have

明日、雪が降るかもしれない。
Tommorow, will snow even fall? It is not known.
It may snow tomorrow.

I think it is best just to treat it as a set phrase though.

Answer 2

In old Japanese か and も are the end particle, sometimes they are combined as かも(かな) and it admires the previous statement with or without a little irony.

Definitions of three end particles in old Japanese dictionary:

か to express wonder, inquirer and irony. ...かなぁ/・・・だなぁ/...だろうか e.g. いづれか

も　(normal particle)to express add the same word 今も...; to suggest a quote or indirect meaning ...もまた; to express minimum ...でも、...せめて e.g. ほととぎす、一声も鳴け(ほととぎすよ、一声で良いから鳴いて欲しい); (end particle) to exaggerate the word (normally)「かも」「しも」「とも」「ども」「やも」「もこそ」「もぞ」

かも　か+も to express admiration and etc. e.g. 立ち別れまく惜しき宵かも(別れが惜しい夜であるなぁ)

(old)しらん=しらぬ (new)しれません perhaps so; both refer a subjective doubt/expectation.

All together (old/middle)かもしれぬ (new)かもしれない = "..., perhaps so in my opinion."