Could you explain why に is used with もらう?


I know we use に to indicate from whom we receive the favor/thing. I don't see
any common sense for that. Naturally, I would use から instead because に
expresses a direction "to/toward" not "from".

=> Could you explain to me the root cause?

>   * 友達 **に** お菓子をもらった。 => I received candies **from** my friend.
>   * 友達 **に** お菓子をあげた。 => I gave candies **to** my friend.
>




It's basically a grammatical reason, not a meaning reason.

Japanese uses three markers for marking core arguments in a clause:

  * が marks the subject (or rather, a subject that isn't also a topic; but let's ignore that for this answer)

  * を marks the object

  * に marks _everything else_

For the most part, when you have three core arguments, the one that isn't a
subject or object is usually a recipient. Since に also (quite separately)
marks a destination or direction, that seems like a normal extension of
meaning - from 'direction of moving' to 'direction of giving'.

However, there are some clear cases where it marks things that aren't
recipients. Causatives are a good example: you end up with three core
arguments (subject, object and overall causer), and the leftover third one is
marked with に - even though that doesn't make sense if you're thinking of it
as a direction marker. 貰う is a similar case: it takes the recipient as subject
and the gift as object, and the leftover core argument - the giver - is marked
with に.

To summarise, because 貰う has three core arguments and already specifies that
the recipient is the subject, the leftover giver has to be marked with the
'leftover core argument marker', which is に.




It's basically a grammatical reason, not a meaning reason.

Japanese uses three markers for marking core arguments in a clause:

  * が marks the subject (or rather, a subject that isn't also a topic; but let's ignore that for this answer)

  * を marks the object

  * に marks _everything else_

For the most part, when you have three core arguments, the one that isn't a
subject or object is usually a recipient. Since に also (quite separately)
marks a destination or direction, that seems like a normal extension of
meaning - from 'direction of moving' to 'direction of giving'.

However, there are some clear cases where it marks things that aren't
recipients. Causatives are a good example: you end up with three core
arguments (subject, object and overall causer), and the leftover third one is
marked with に - even though that doesn't make sense if you're thinking of it
as a direction marker. 貰う is a similar case: it takes the recipient as subject
and the gift as object, and the leftover core argument - the giver - is marked
with に.

To summarise, because 貰う has three core arguments and already specifies that
the recipient is the subject, the leftover giver has to be marked with the
'leftover core argument marker', which is に.

