QuoteBoth Joshua in this episode and DeWitt in his book say that Epicurus was definitely not a complete empiricist. I'm curious why that is.
Well, of course I'm influenced by DeWitt in arriving at this conclusion, but I think it's a good one.
Quotea person who supports the theory that all knowledge is based on experience derived from the senses.
Sensation, in my view, is the body's (and by extension, the mind's) system for the passive collection of environmental data. Like a Mars rover, the human body has "instrumentation" that gathers information about it's surroundings--unlike a Mars rover, these instruments are biological.
I use the word passive advisedly; the ancient Epicureans used the classic example of a 'square tower seen from far away' to demonstrate that the sensations were always accurate (another term chosen with care); the fact that a square tower looks round from far away is not, to the Epicureans, a case of failed sensation. "The eye is reporting accurately what a square tower looks like from far away".
This appears at first glance to be a kind of fudging--an end-run around the Skeptics' objection to the reliability of sensation. But the job of the senses is merely to report data. The senses do not have a role in analyzing that data. Analyzing sensory input is a higher-level function, and therefore not directly epistemic.
A strict empiricist gets that far, and stops. Sensation is the only direct source of knowledge. An Epicurean isn't done yet, though. It's true that sensation is a direct source of knowledge, but that gives us just one leg of the canon.
If the canon is to be understood as a valid theory of epistemology, then the other two legs must not rely on sensation for their source of knowledge. They must be direct sources of knowledge in their own right.
So when we look at pathe and prolepsis, we must begin to understand these as co-equal with sensations and not contingent upon them. A mind deprived of sensory organs would not experience sensations, which are oriented toward the external world, but it would still experience pathe, 'feelings', because the feelings are oriented toward perceiving the internal world of the mind itself. This is a difficult concept to get hold of! If Epicurus had not allowed for mental pleasure and mental pain, his epistemology would fall apart here.
Prolepsis is an even more difficult concept to get hold of, and I really continue to struggle with it; from my understanding, this involves conceiving of things one has not sensed or felt. You might have sensed a horse with your eyes, and likewise a man; but your "experience" of a centaur is a mental preconception of something you have not sensed. I am VERY open to being corrected on this point!
Each leg of the canon is a refutation of the ideas of other schools. The Skeptics thought knowledge was impossible because the senses were flawed. Epicurus' treatment of sensation is meant to answer this objection.
Plato had argued that teaching someone something they didn't already know was impossible, because unless they had an idea of the thing they could not begin to understand what was being described to them. The Prolepsis answered this quandary by proposing that new images could arise in the mind out of the mingling of previously-imprinted felt or sensory images.
And the inclusion of the feelings meant that the 'good' could be yanked down from Plato's unsubstantiated 'universal form of the good', that it could be known directly and understood by every human of average capacity, and that this good could be pursued by all as pleasure.
To a first-order approximation, I think it's fair to use the word empiricism--with caution!--to describe Epicurus' approach to understanding things in nature. But when we analyze the canon in the fullness of its utility for the student of philosophy, the word 'empiricism' comes up short.