Nate Silver discusses the Fox/Hedgehog division in his excellent "The Signal and the Noise" frequently, and he largely takes on the meaning proposed by Phillip Tetlock in his book on expert political judgement.

The idea that Tetlock puts forward is that pundits divide into two categories, Foxes and Hedgehogs. Hedgehogs explain the world and make predictions according to one large all encompassing principle. Foxes don't, and apply different principles to different circumstances. Tetlock concludes, and Silver endorses this, that Foxes are better at understanding the world than Hedgehogs.

An example might be the (proposed) principle that free markets lead to increased prosperity. A hedgehogy capitalist might state the above as a broadly applicable principle. A foxy capitalist might opt for something like: "yes, many times increased freedom makes us prosper, but sometimes it doesn't, it depends, let's talk about the specifics".

I take this to be an argument about complexity. The fox side of the argument is roughly that the world is more complex than most people allow for, and one principle or world view will usually not cover an area of knowledge well.