TerryWinograd and FernandoFlores?, in their brilliant work UnderstandingComputersAndCognition, characterize a particular stance towards life (philosophy? problem-solving? the universe?) as the rationalistic tradition. I cannot offer a short definition here, precisely because their book has deeply undermined my confidence in such efforts. The words below, at best, capture only single isolated features of this worldview.
One aspect of this tradition is its emphasis on this recipe for decision making:
List all strategies.
Determine consequences of each strategy.
Compare the consequences and choose.
This is one piece of the rationalistic tradition that BigDesign relies heavily on. If you would be UnderstandingBigDesign, pro or con, you have to position it properly in its tradition.
List all strategies?! See BranchPruning.