Optical Phenomena (Not Necessarily Just Optical "Illusions") And Their Relationship To Prolepsis / Anticipations

    I don't see that we currently have a a thread devoted to the relationship between optical phenomena, like the attached video, and how they relate to anticipations / prolepsis.

    In this example, when you play the video you see pretty clearly the outline of a shape. When you stop the motion the outline largely if not fully disappears.

    I think it's pretty clear from our past discussions that we do not think Epicurus would tell us that the eyes themselves are seeing this shape. So is this a functioning of prolepsis/anticipations that the mind is assembling from repeated viewing of the object the pattern that is created in this example?

    I think optical examples like this can help us clarify our use of the anticipation / prolepisis phenoma along exactly the lines Lucretius discusses in book four of his poem.

    (Note that the music came with the video - not mine - and you may want to mute it.)


    As far as I can tell, in this video, our eyes are seeing a square. A stable square does appear in the movement as the background moves from left to right.

    We are calling it a "square" because the shape we are seeing fits our preconception/basic grasp/mental sense of a square.


    I agree, this does fit the examples Lucretius uses (e.g., a still horse in a river appearing to move when you are on the horse, or a still boat appearing to move when you are in a moving boat), but I think our school listed a lot of examples of "illusions" (i.e., appearances with low symmetry with the original source) before making the argument that, nevertheless, our sensations of appearances are the basis of understanding.


    Our preconceptions/basic mental grasps are just another sensation... they may well be illusionary in some cases (many people have a basic idea of an eternal Jesus), but we must, nevertheless, rely on preconceptions/basic mental grasps for any thought to happen!

    (Technically speaking, an incorrect pro-lepsis/ anticipation is called a hypo-lepsis/ supposition).

    Yes, and I almost stayed away from mentioning "illusions" entirely, because i think the basic point is first "what is it that we are seeing" and "how do we decide that we see a "square" and "what is it we are labeling as a square.

    We could use other words (for example, other languages) and mean the same thing. But we're not talking about a "form that we are remembering from before we were born" or a "form of a square that we reason to exist in nature and of which this video demostrates an example"

    We're doing something else, I presume - something like assembling in our minds using a natural faculty a pattern that we choose to call a square, and which when we compare to other things we can see, shares a common set of characteristics. But apparently all this is going on in our minds through nature.

    And I also presume that we would assemble and recognize this pattern even if we were an infant and had never been exposed to any other examples of "things that are square" whatsoever. We aren't born with "the idea of a square" but we are born with a faculty that assembles what we eventually term the idea of a square.

    I think in talking though what the mind is doing we can make clear that what we are seeing is "real" without it partaking in any kind of mystical divine form or hocus-pocus.

    We aren't going to be able to make productive use of understanding "prolepsis" in ethics or anything else if we can't articulate from basic examples what we are talking about.