Parsing potential phrase modifying a noun


[From Hirameki Hatsume-chan Vol 1, chapter
7[1](https://i.stack.imgur.com/6g2Az.jpg)](https://i.stack.imgur.com/6g2Az.jpg)
How does the sentence in the third panel translate, and who is doing what to
whom? Is it a potential and the どうぐ is "enabling" him to have good dreams or
is it passive and the 見る verb used to mean "show"?




> ［（私が/人が）いい夢を見られる］道具  
>  A tool [with which (I/people) can see a good dream]

いい夢を見られる is a relative clause modifying 道具.  
Its non-relative equivalent would be:

> 道具 **で** （私が/人が）いい夢を見られる。  
>  With a tool, (I/people) can see a good dream.

So the 見られる is potential. Its subject can be "I", "we", "you" or "people" who
will have a good dream using that tool. The particle で goes missing when you
turn the sentence into the relative clause.

Compare:

>   * 私がペン **を** 使った。-- I used the pen.  
>  → ［私が使った］ペン -- the pen that I used (を goes missing)
>
>   * 道具 **で** 火を起こす。 -- (I) start a fire with a tool.  
>  → ［火を起こす］道具 -- a tool with which (I) start a fire (で goes missing)
>
>   * 筆 **で** きれいな字が書ける。 -- (I) can write beautiful characters with a brush.  
>  → ［きれいな字が書ける］筆 -- the brush with which (I) can write beautiful characters.
> (で goes missing)
>
>




> ［（私が/人が）いい夢を見られる］道具  
>  A tool [with which (I/people) can see a good dream]

いい夢を見られる is a relative clause modifying 道具.  
Its non-relative equivalent would be:

> 道具 **で** （私が/人が）いい夢を見られる。  
>  With a tool, (I/people) can see a good dream.

So the 見られる is potential. Its subject can be "I", "we", "you" or "people" who
will have a good dream using that tool. The particle で goes missing when you
turn the sentence into the relative clause.

Compare:

>   * 私がペン **を** 使った。-- I used the pen.  
>  → ［私が使った］ペン -- the pen that I used (を goes missing)
>
>   * 道具 **で** 火を起こす。 -- (I) start a fire with a tool.  
>  → ［火を起こす］道具 -- a tool with which (I) start a fire (で goes missing)
>
>   * 筆 **で** きれいな字が書ける。 -- (I) can write beautiful characters with a brush.  
>  → ［きれいな字が書ける］筆 -- the brush with which (I) can write beautiful characters.
> (で goes missing)
>
>

