Economics and Abstraction

I found the following joke in an economics text "Economics Principles and Policies" by Baumal et al.

The joke is filed under The Need for Abstraction;

Three people stranded on an isolated island - a chemist, a physicist, and an economist - with ample supply of canned food but no implements to open the cans. In debating what to do, the chemist suggested lighting a fire under the cans, thus expanding their contents and causing the cans to burst. The physicist doubted that would work, he advocated building a catapult with which they could smash the cans against some nearby boulders. They then turned to the economist for his suggestion. The thought for a moment and announced his solution: 'Let's assume we have a can opener'.

I find this joke hilarious. Not least because its quite relevant today with the Federal Elections coming up and the Coalition especially touting their superior management of the economy. Perhaps there is something abstract about that.