This was reworked from my first tutorial essay for general philosophy with Bernhard Salow, who provided lots of helpful guidance and encouraged me to submit the end result to JPhil. It made it out for review, but the journal (correctly!) went instead with Haziza’s much better reply, ‘How Knowledge Entails Truth’. My thinking about the place of deduction in philosophy has changed a lot since writing, thanks to Tim Williamson (on abduction) and Daniel Kodsi (on inconsistency as self-disagreement). I learned a lot through the process of writing this, though, and mostly stand behind it.