The most reasonable gloss on "You need a math PHD to code Dwarf Fortress" is "Necessarily, if someone codes Dwarf Fortress, they have a math PhD." The modality

The most reasonable gloss on "You need a math PHD to code Dwarf Fortress" is "Necessarily, if someone codes Dwarf Fortress, they have a math PhD." The modality "necessarily" is widely understood to refer to possible alternative states of affairs, not merely those states of affairs which are actual. In other words, if an alternative state of affairs is possible, in which someone (whether Tarn Adams or someone else) codes Dwarf Fortress without a math PhD, then it is not true that it is necessary to have a math PhD to code Dwarf Fortress. Most people in this thread believe that since a math PhD did not play a crucial role in Adams's ability to develop Dwarf Fortress, then it is true that such an alternative state of affairs is possible. (The language of "alternative universes" - usually called possible worlds in the literature - is one way of getting at this.)