Saturday, November 06, 2010

Inviddying Terminology

I've been re-reading Quee Nelson's The Slightest Philosophy.

One of the classic issues that comes up in her book is the case of the circular coin viewed at an angle. If you take a photo from that angle, and trace your finger around the coin's image, your finger will trace an ellipse, not a circle.

So the question arises: What did you really see in the first place?

A) A a circular coin?

B) An elliptical image?

Nelson says we see the circular coin. It's a minority position in post-medieval philosophy. But she has some intelligent company, such as David Kelley, a contemporary philosopher, and Thomas Reid, an 18th Century philosopher.

All 3 deny that we usually see an elliptical image.

But since we are are in fact capable of noticing the ellipse, they need some technical term for that noticing, something other than simple "seeing". But their terminologies diverge:

Reid calls it "attending to the visible figure of bodies".

Kelley calls it "reductive focus".

Nelson, in a humorous coinage, calls it "inviddying".

Divergent technical terms
can be a bucket of worms
that make it hard to see
where thinkers really agree.

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