Please help me figure this one out.
Why does so many people write "For illustration purposes" when the only purpose is to illustrate? Is this even correct at all? I mean, since the word "illustration" is a noun, should it be "For illustrative purpose" instead?
The point is that we should not confuse the illustration with 'reality'. The illustration is intended to highlight certain features whilst omitting other, non-essential, parts. By adding 'for illustration purposes only', the writer wants to draw our attention to the fact that the illustration is selective in what it shows.