Why is a raven like a writing desk? Two nice analogies

I like a good analogy. When well designed, they can convey the unfamiliar through the familiar. Of course, they can also mislead if we don't pay attention to the differences as well as the similarities. Here are two I've come across recently. First, one from Australian Sustainable Energy by the Numbers, a useful report from the University of Melbourne into the possibility of getting Australia to 90% renewables (or low carbon) in a short time frame at a decent cost with (hopefully) some more realistic assumptions than this report.

"Our cruise ship is leaking badly. The captain is advised by the engineer to start the bilge pumps but the accountant says this will be too expensive and would cut into profits. The captain makes a tough decision; the passengers will have to bale. An argument breaks out between the staff and the passengers about whether to bale with spoons or glasses. The passengers argue for glasses but the staff for spoons because of the likely breakage of glasses. The hospitality manager comes up with a brilliant solution. The passengers should drink more beer and champagne and pee over the side."

- Peter Seligman, Australian Sustainable Energy by the Numbers, 61.

H/T Dave.

And I couldn't go past this recent letter to the editor in the SMH.

"And what about this great big garbage tax? Why do I have to pay to have my garbage collected when I can dump it in the bush for nothing? My little bit doesn't make any difference to world garbage levels, and when it rolls to the bottom of the gully I can't even see it. Call me a garbage sceptic, but show me the science. If garbage is bad why do we produce so much?

"When I went overseas there was garbage lying everywhere. Other countries don't have great big garbage taxes. They make cheap stuff and we can't compete. Until every country in the world adopts a garbage price, our great big garbage tax is economic suicide. Garbage is crap."

- David Hale Gordon, SMH letters to the editor, 25th March 2011.