Wow! I'm super impressed how literally swapping a few phrases from the Tunnel Goons rules somehow changes the entire focus and flavor of the game. And into something I feel more personally invested in, as a player and a DM. (It's the first jam entry that I actually want to run for TRPG newbies who have philosophy backgrounds.) 

I like the implied caveat -- that the Action Rolls are not a test of the Player Characters' beliefs/philosophies/ideologies, so much as their ability to win over hearts and minds. 

Some actions seem intuitive enough:

• detective work = Explorer + Logical deduction + Pen & Paper

as opposed to...

• forensic science = Philosopher + Empiricism + Pen & Paper

And others actually help to make useful rhetorical distinctions:

• proselytizing = Cultist + Religious Faith + (Holy) Book

vs.

• evangelization = Philosopher + Religious Faith + (Holy) Book

That said, it feels like some of the Ideas are conceptually tied to specific Classes, which goes against the spirit of the original rules.

For instance, I'm not entirely sure how Solipsism can benefit a Cultist roll unless perhaps the PC is a LaVeyan Satanist.

Likewise, if a player choose Falsifiability as an Epistemic Principle, can that be used with an Explorer roll while hunting a Dire Black Swan? (Especially if the other party members are convinced that it's a hoax, and we're on a wild goose chase.)

Suggested alternate Settings:

• Agora
• literal Desert of the Real

Suggested alternate play modes:

• Cartesian rules - roll under the DS for the action to succeed (calculate damage based on the difference) 
• Buddhist rules - losing all Certainty is the win condition

Suggested Items:

• Map (for illustrating semiotics, among other things)
• Pocket watch (mechanical)
• Armillary sphere

Suggested encounters:   

• Laplace's Demon (DS12 with resistance to Explorer actions and Empiricism)
• Descartes' Demon (DS10 with resistance to Philosopher actions)
• Neo-Zarathustra (DS10 with resistance to Cultist actions; will eternally recur at DS10 after being defeated unless all party members climb the rope of self-mastery above its abyss)
• Anti-Oedipus (DS8) + Bodies Without Organs as minions (singular formless rhizome but represented as a variety of discrete oozes/jellies/gelatinous blobs for mechanics; DS6 per cellular element)