Especially when it comes to assumptions that underpin your business and its strategy. Most businesses have assumed that (a) global warming is happening and (b) we are approaching an energy supply crisis.
In the past two days both of these tenets have been challenged:
Firstly, a report challenging global warming (observing that many weather stations that were once in rural areas now find themselves next to airports or urban developments so naturally recorded temperatures will rise). Secondly, we have an observation that our ability to innovate and find new energy sources will outstrip increasing demands for energy.
In a changing world be careful in what you take for granted. It will probably change. Remember the unbounded spread of capitalism?
 Leake, J. The world may not be warming, say scientists. Sunday Times 14 February 2010.
 Worstall, T. The problem with calling an end to the world. Adam Smith Institute. 15 February 2010.