Thank you Mounia for your reply. I do look forward to future videos of the methods employed, as there always arise questions about details of methods which visuals quickly answer. I apologize for my question's lack of clarity (I know what I want to say but not how to say it). My interest is in the equivalence between the haptic and visual modalities with respect to comparing the whole of two differential concepts simultaneously, which seems paradoxical. Your dissertation motivated me to pursue this in the haptic modality side by side with the visual.

In your dissertation, you showed (using the Tactos method, section 4.8.2) how the inner intentive (efferent) concept is contrasted in the mind with the feedback from a second urgent feedback field (afferent). (E.g. using touch to discern velocity in the motor expression field while visually comparing that effort to feedback in a visual field of differing size/velocity). You used circles then too (one for touch, to discern the efferent/motor boundary, and one for screen feedback, to discern a feedback velocity which was a different scale). This Ebbinghaus test is very intriguing for me because it extends the concept where I hoped you would go with it -- how our belief that visual comparison can do what touch cannot must be an illusion. We cannot see the whole of everything about one concept, and also see the whole of "something else" simultaneously to compare them, let alone form a third "everything" consisting of differential contrast. Yet we believe we can, and call it "objectivity". In Tactos, you demonstrated with the haptic modality that we cannot know whole and part simultaneously, let alone the whole/part (unit concept) of two velocity fields of different scales at the same time. With touch, we must move the detector to discover the outer boundary; so we can't know locus, and also know speed and direction. Vision thinks we "can". This was really motivating for me.

This Ebbinghaus example demonstrates that vision has an illusion it can know the whole of multiple concepts simultaneously, plus find time from somewhere to confirm differential contrasts too. I mention memory, because it seemed to me this is how you resolved it - if we cannot hold more than one everything in a concept of simultaneity (Susie Vrobel), then we must be separating "everythings" using the concept of "memory" (spatial and temporal separation). The illusion comes about because we change focus from one illusion to another (the first illusion being that we can confirm a first contrast which is already 3 everythings, and the second being an effort to compare those with a second trio). We cannot see difference unless we have a bias; yet we believe we can have bias and be objective. And oddly, we think we can form a contrast in vision using more time than the visual epoch affords. Touch enlightens us -- if touch, being bidirectional and of minimal reciprocal radius, cannot do this, certainly vision, which is essentially unidirectional and distal, cannot.

Apologies if this clarification blurs things even more, I hope though I expressed the main idea.

Dear colleagues:

I am not sure this relates directly to your discussion, but you may be interested to know that it is possible to have the illusion one's arm is moving even past the point where no more arm velocity is felt and, in fact, it would be impossible for he arm to extend any further. Thus, the perception of displacement and of motion are being maintained separately and simultaneously in the mind. This is called the ochulobrachial illusion and is a remarkable counter to the famous "vision teaches touch" experiments of Rock and colleagues. There are several other examples of displacement and velocity perceptions being perceived separately (some are kinesthetic/tactile in origin, some vestibular, etc.), which I could discuss further if you message me on ResearchGate. If you simply wish to look up the ochulobrachial illusion to see if it is relevant to you, that work occurred in James Lackner's lab (he was my dissertation advisor many moons ago) so that will give you an author and key phrase to find it easily.

Hello Ben, yes that would be terrific, thank you. I will message you then. Thanks so much

-- Lonny