D&D 5E (2014) How does the errata on hiding affect the mask of the wild ability of the wood elf?

[EzekielRaiden]

The latest Basic Rules with the errata, says:

‘You can’t hide from a creature that can see you clearly.’

Thus:

You can hide from a creature that can partially see you.

I'm a bit late to the party here (and someone already replied with the core point), but there's actually a very good reason you can't make this logical leap. That is, first we can re-cast both statements into logical "if-then" form: (1) "If a creature can see you clearly, then you cannot hide from it." (2) "If a creature can partially see you, then you can hide from it." These are statements of the form, "If A, then not-B" and "If C, then B." But C and A are not precise logical complements: A and C are two points on a spectrum. The only way this connection could work is if it was phrased as, "If and only if a creature can see you clearly, then you cannot hide from it." Being clearly seen is a sufficient condition for being unable to hide, but being partially seen is not sufficient for being able to hide.