On a recent Way With Words podcast, a caller asked whether a half-full trash can should be referred to as half full, or half empty, and whether this trash can was symbolic of optimism or pessimism.
 
The question is in relation to the expression “is the glass half full or half empty?” In this expression, the glass is presumed to have something good in it, cold water, wine, etc., so the optimist sees it as a half full glass and the pessimist sees it as half empty.
 
I would argue that the trash can variant is not a word or language related question. The problem is that the trash can variation breaks the metaphor of the original expression due to sloppy or inattentive thinking. One cannot rationally subsitute words or phrases in a colloquial expression, metaphor, etc. because the original is not literal.
 
A person who says they are hungry enough to eat a horse is not offering to do so. They are merely saying they are very hungry. This person is also not offering to eat a spectrum of animals, such as zebras, dogs and raccoons. Substituting these animals does not offer a new situation that is of any use. The expression “I’m so hungry I could eat a raccoon” means nothing.
 
One more example. There’s an old British expression “carrying coals to Newcastle.” Newcastle, England used to be the hub of the British coal trade. There was so much coal there it wouldn’t have made sense for a person to carry more coal there. So the expression basically means an ineffectual, pointless or redundant act. Now, let’s say I bring several large bags of marshmallows to Newcastle. What, I wonder, does “carrying marshmallows to Newcastle” mean, in a philosophical sense? It means nothing.

I had a quick hint for public speakers and speechwriters on how to make a speaker more statesmanlike. Don’t have important people make “housekeeping” remarks, like:

• I’d like everyone to thank our sponsors
• There’s a great buffet at the back of the room
• Don’t forget to attend those birds-of-a-feather sessions this afternoon
• Drop by our solutions booth out there on the tradeshow floor for a chance to win a Zune
• Take your game card around and have it stamped at all of our partner booths
• Etc.

Could you imagine Churchill starting a speech this way? Or JFK beginning his famous 1961 Berlin speech, “First, I’d like to thank Lufthansa for kindly providing us with a DC-9 while we’re here in Germany. Please stop by our hospitality suite at the Brandenburg Gate. OK, let’s get started. I’m sure you’re all anxious to get out of here and visit the biergarten.”

Here’s a perfect example of the right way to do it, from a video of a Steve Jobs keynote. I believe this was taken at Apple’s sales conference in Hawaii in 1983. He starts with a four-word intro: “Hi, I’m Steve Jobs.” This is actually a joke, since everyone in the room knows exactly who he is. Without missing a beat, he launches directly into his prepared remarks:

“It is 1958. IBM passes the chance to buy a young, fledgling company that has invented a new technology called Xerography.”

There is nothing extra here. It is spare and clean. There is nothing to detract from Jobs’ stature. He is confident, almost courageous. Some people use housekeeping remarks as a form of “um uh uh um” to help them warm up and collect their thoughts. Too much of this and they sound less statesmanlike and more like a gameshow host or an actor in an informercial.