The difference between ～ようだ, ～ように見える, ～ように思える and ～みたい


In a Japanese English grammar textbook,
["seems"](http://eow.alc.co.jp/seem/UTF-8/) is translated as `～のように見える`, for
example:

> He _seemed_ to have been ill.  
>  病気であった **ように見えた** 。

I've also seen "seems" written as
[`～（の）ように思える`](http://eow.alc.co.jp/search?q=%E3%82%88%E3%81%86%E3%81%AB%E6%80%9D%E3%81%88%E3%82%8B)
in various example sentences on Space ALC:

> 何の効果もない **ように思える** 。  
>  It doesn't _seem_ to have an effect.

What's the difference in meaning and usage between
[`～（の）ようだ`](http://eow.alc.co.jp/search?q=%E3%82%88%E3%81%86%E3%81%A0),
[`～（の）ように見える`](http://eow.alc.co.jp/search?q=%E3%82%88%E3%81%86%E3%81%AB%E8%A6%8B%E3%81%88%E3%82%8B),
[`～（の）ように思える`](http://eow.alc.co.jp/search?q=%E3%82%88%E3%81%86%E3%81%AB%E6%80%9D%E3%81%88%E3%82%8B)
and [`～みたい`](http://eow.alc.co.jp/search?q=%E3%81%BF%E3%81%9F%E3%81%84)?




As for the difference between みたい and よう, it is too subtle for me to tell.

Between the various endings after みたい, they indicate how indirect the
observation is (i.e., how much inference is involved).

  * だ is declaration, so ようだ is the most certain among the endings using よう.
  * ように見える adds the hedge 見える, meaning that it is directly observed, but is less certain than ようだ.
  * ように思える adds the hedge 思える, meaning that a thought process is involved, so it is less certain than ように見える.




As for the difference between みたい and よう, it is too subtle for me to tell.

Between the various endings after みたい, they indicate how indirect the
observation is (i.e., how much inference is involved).

  * だ is declaration, so ようだ is the most certain among the endings using よう.
  * ように見える adds the hedge 見える, meaning that it is directly observed, but is less certain than ようだ.
  * ように思える adds the hedge 思える, meaning that a thought process is involved, so it is less certain than ように見える.

