Possible Clues:

• Work the man's displayed in street as a philosopher
• Protagoras, notably
• It's posh, if contrived, one might plausibly argue
• One's pedantic so to sit below the shop
• One whose logic is faulty
• Philosopher's concession, greeting holy person
• Skillful reasoner
• One using clever but wrong arguments
• Specious reasoner
• One whose reasoning is faulty