Re: Object Constancy

From: Taylor, Karl (
Date: Thu May 01 1997 - 16:57:06 BST

> Here are two events that will cast exactly the same
>"shadow" on your retina: (1) a faraway sphere, moving
>closer and closer; (2) a small sphere, growing bigger and
>bigger. You would see the first thing as being the same
>size, despite the growth of its shadow on your retina, but
>you would see the second thing as growing (and that's not a

I think I am a little clearer about this distinction.
But I'd like to be a little clearer still.

Here's something that was also part of my original reasoning
over this question but I couldn't quite grasp it at the time:

Isn't the size of an object one "cue" that we use when we see to help
determine the distance of an object? (ie. as Della says, aren't the two
things related?)

For example: your growing/ moving sphere, if seen in a pitch black room
(I guess it would have to be a glowing growing/ moving sphere) would be
ambiguous without any further "cues" such as shadowing etc., wouldn't

So, although some distinction is fine generally, aren't there examples
where there is no clear distinction?

(I guess you might say that there are exeptions to any rule. I'm not
trying to be pedantic but I would like to hear what you think about

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