Possible Clues:

• Head of the Latin house, that's me, by decution
• Following the first of April, or I get it by deduction
• Derived by logic, Latin
• Presupposed through reasoning
• Not based on previous study
• Derived by logic (Latin)
• (Reasoning) from first principles (Latin)
• From a general principle to its consequences
• Deductive, as reasoning
• By deduction, it's the top of a house I be