I wonder why we use "accessible to" as a meaning of "can be accessed from", for example, "How to Make Your Blog Accessible to Blind Reader".
It makes more sense to me when using 'accessible from'. Is it wrong to use 'accessible from'?
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Except, we don't. However, it can be used as a meaning of can be accessed by.
This is correct as you are giving blind readers access to the blog.
This implies that you can access your blog from blind readers! Not what the author had in mind, I imagine.
Some other examples:
The phrase accessible to makes sense because it parallels the noun form, access, which routinely takes the preposition to when referring to the persons or things doing the accessing.
The preposition from is used to describe geography that suggests a point of entry or origin.
Note that the destination of the access still takes to.
The adjectival form accessible is handled similarly