Related Clues:

• Illusionist's look for mother -- a straight-thinking individual
• 'If ... then' sort of thinker
• Reasonable chap has record at home about spies
• Having good reason to join the network welcoming spies
• Reasoned thinker
• Rationalist showing way to access site infiltrated by spies
• One can make sense of a coiling formulation
• Academic in the field of formal reasoning