I think this is well worth exploring because it's probably the front line of the way the Epicureans would have distinguished their approach to the search for truth as opposed to the use of "formal logic" by the other philosophers. Looking for and setting up "rules" that harden into inflexibility is a prescription for disaster, and I would expect that Epicurus would be looking for ways to describe a properly flexible approach that always takes into account new facts and new circumstances regardless of what "rules" of virtue or piety have been developed formally over time.
Seems to me that Frances Wright was attacking this issue also in saying something to the effect that "theory" is an enemy of truth. I'll look for that cite.
From Chapter 15 of A Few Days In Athens, Leontium speaking:
Quote“I apprehend the difficulties,” observed Leontium, “which embarrass the mind of our young friend. Like most aspirants after knowledge, he has a vague and incorrect idea of what he is pursuing, and still more, of what may be attained. In the schools you have hitherto frequented,” she continued, addressing the youth, “certain images of virtue, vice, truth, knowledge, are presented to the imagination, and these abstract qualities, or we may call them, figurative beings, are made at once the objects of speculation and adoration. A law is laid down, and the feelings and opinions of men are predicated upon it; a theory is built, and all animate and inanimate nature is made to speak in its support; an hypothesis is advanced, and all the mysteries of nature are treated as explained. You have heard of, and studied various systems of philosophy; but real philosophy is opposed to all systems. Her whole business is observation; and the results of that observation constitute all her knowledge. She receives no truths, until she has tested them by experience; she advances no opinions, unsupported by the testimony of facts; she acknowledges no virtue, but that involved in beneficial actions; no vice, but that involved in actions hurtful to ourselves or to others. Above all, she advances no dogmas, — is slow to assert what is, — and calls nothing impossible. The science of philosophy is simply a science of observation, both as regards the world without us, and the world within; and, to advance in it, are requisite only sound senses, well developed and exercised faculties, and a mind free of prejudice. The objects she has in view, as regards the external world, are, first, to see things as they are, and secondly, to examine their structure, to ascertain their properties, and to observe their relations one to the other. — As respects the world within, or the philosophy of mind, she has in view, first, to examine our sensations, or the impressions of external things on our senses; which operation involves, and is involved in, the examination of those external things themselves: secondly, to trace back to our sensations, the first development of all our faculties; and again, from these sensations, and the exercise of our different faculties as developed by them, to trace the gradual formation of our moral feelings, and of all our other emotions: thirdly, to analyze all these our sensations, thoughts, and emotions, — that is, to examine the qualities of our own internal, sentient matter, with the same, and yet more, closeness of scrutiny, than we have applied to the examination of the matter that is without us: finally, to investigate the justness of our moral feelings, and to weigh the merit and demerit of human actions; which is, in other words, to judge of their tendency to produce good or evil, — to excite pleasurable or painful feelings in ourselves or others. You will observe, therefore, that, both as regards the philosophy of physics, and the philosophy of mind, all is simply a process of investigation. It is a journey of discovery, in which, in the one case, we commission our senses to examine the qualities of that matter, which is around us, and, in the other, endeavor, by attention to the varieties of our consciousness, to gain a knowledge of those qualities of matter which constitute our susceptibilities of thought and feeling.”