For good

We speak more than we know when we use the idiom 'good' to mean 'ever after' ('he's back for good'; 'she's gone for good' ... do we always use it, I wonder, if this dative motion-from-and-towards sense?) Intuitively we seem to be saying: the temporary, the changeable, the uncertain is bad; the known, the unchangeable, the eternal is good. Which is to say, we speak the subconscious affective fantasy of our restless hearts -- peace -- and not the conscious knowledge of our minds, that looks upon anything that has come or gone 'for good' and sees desolation.