Fox vs Hedgehog is a model of thought proposed by Isaiah Berlin. A hedgehog has one big idea and attempts to explain phenomenon they encounter in terms of their big idea. A fox has many small ideas, and does not attempt to boil situations down to one particular view. Reference class forecasting (and the inside and outside view framing) can be seen as a slightly different approach to the same idea. It was found during the Good Judgement Project that fox type thinkers dramatically outperformed hedgehog type reasoners in making predictions.
One common error in attempting to become more of a fox type thinker is to view the process as an attempt to determine which model it is "correct" to apply in a particular situation. This is just being a slightly clever hedgehog. Actual foxy thinking aggregates cost-benefit from across all the potentially applicable models, weighted by their likelihood. Ironically, this might be referred to as hedging one's bets.