"lost and found edges on object"

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I`m currently reading one of Harold Speed`s books on drawing. In it he recurrently speaks about lost and found edges. (I know that there has been an edges thread, yet I think my question is unique).I`m having a hard time understanding exactly what is meant by lost and found edges on an object(that is lost and found edges being found\observed on the same object and why?). In her book on drawing J.Aristides defines a "lost edge" as where the value of an object and the background are the same- so the edge is consecuently lost.This is easily understood. However if I understand H.Speed right he`s talking about the rythmic use of lost and found edges ( he speaks nothing of value.A lost edge is according to him an edge that is not distinct ( "cut" ) -one that blurres into the backround( even though the value is different(?).He talks about lost edges occuring when the artist adopts a wide visual field, and does not focus on single objects. He says that when you focus on single objects they always have hard edges ("found edges").-I`m having a hard time observing all this myself.Aristides definition is straightforward and can be observed - are they talking about the same thing?

And does our binocular vision have anything to do with us experiencing lost or found edges?If you close one eye - all edges appear to be hard.

I really appreciate all answers - if you have any good visual example (from e.g a classical painting you can think of it would be great).

[Art_Addict]

Just 10 threads below yours : http://www.conceptart.org/forums/showthread.php?t=125553

And here's the link to James Gurney's blog that Elwell posted in that same thread : http://gurneyjourney.blogspot.com/2008/06/depth-and-edges.html
(http://gurneyjourney.blogspot.com/2008/06/depth-and-edges.html)