The quirky option of referring the issue to Siro or Philodemus comes from On Ends Book Two:
When I had thus spoken, Triarius said, ‘I have friends to whom I can refer these questions, and although I might have made some answer myself, still I would rather look to men better equipped than myself.’ ‘I believe you mean our friends Siro and Philodemus, not only excellent men, but men of very great learning. ‘You understand me rightly,’ said he. ‘Agreed, then,’ said I, ‘ but it were fairer that Triarius should give some verdict about our disagreement.’ ‘I reject him on affidavit,’ said Torquatus with a smile, ‘as prejudiced, at all events on this subject, since you handle these topics with some gentleness, while he persecutes us after the fashion of the Stoics.' Then Triarius remarked: ‘At least I shall do so hereafter with greater confidence. For I shall be ready with the doctrines I have just listened to; though I shall not attack you until I see that you have been primed by the friends you mention.' This said, we put an end at once to our walk and our debate.