Oh here is a mushrump Phylosopher! shotte vppe since yesterday:

By establishing adpositions as a constantly referred to but never really demonstrated language category, this book has provided a basis for the theory of the linguistic category. […] Adpositions could be considered a clear-cut category if one relied on syntax only, for one simple reason: the are specialized in function-marking.

But unfortunately all that his long-winded explanation amounts to is unconvincing rationalization by its tendency to epithetize a counter argument.

The versatile anther is an important step up in flowering plant evolution and it may be the most widespread of all simple anther types.