In Reply to: A cup half full... posted by Delphine on February 15, 2009 at 20:08:

: A cup half full or half empty. Can someone tell me the exact proverb and where it comes from?
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Gary Martin alludes to this (in a formal entry on this site) at http://www.phrases.org.uk/meanings/butter-side-down.html, and alludes to it being a litmus test for optimism or pessimism. The linked cartoon makes the same point.
I don't think it's a proverb, and it may even be stretching things to call it a phrase. It's more a concept - pschologists seem to like it, so maybe one of them originated the comparison. But I'll have to leave to someone wiser than I am to (try to) find a first use. (GC)