Possible Clues:

• A poet I recognized from previous knowledge
• 'Derived by logic, without observed facts (1,6)'
• Short month, otherwise I worked with deductions
• Based on theory (Latin)
• Like reasoning from cause to effect
• It was deduced by taking port during short month
• Based on deduction instead of experience
• Like some reasoning that's excellent, senior monk admitted
• It comes from the Latin, as far as one knows
• Based on theory instead of fact