This is so hard to interpret, it could be philosophy

Although I like Runeson's paper, there are times when it seems to me he can be equivocal.  Here's a sample:

Not even for static monocular viewing conditions does the notion of equivalent configurations capture the relevant conditions for perception. It is therefore without necessary consequences for the nature of perceptual systems. Granted, the analysis of equivalent configurations can help in constructing and analyzing illusory demonstrations. In such cases, perception can yield outcomes that are erroneous in at least some respects. This is to be expected from the view of perception as information-based and functioning through inherent compatibility with environmental constraints.  (Runeson, 1988, p. 302).

Now, in the first sentence, he could be implicitly limiting himself to "static monocular viewing conditions in the Ames Room", or not.  It's clear he doesn't think that there are equivalent configurations in the Ames Room.  Natural physical constraints, he proposes, rule that out. But, does he think this holds more generally?  There are times when he suggests that we can't rule this out.  He thinks it's hard to confidently conclude that "There exist no equivalence breaking evidence"; that would proving a negative existential.

In the next sentence, he suggests that equivalent configurations have no necessary consequences for the nature of perceptual systems, which sounds kind of dismissive of the enterprise of studying them.

But, then, in the third sentence, he suggests that there could be some use for the analysis of equivalent configurations.  Then, continues to suggest that sometimes there could be equivalent configurations, so that there could be somewhat erroneous perceptions and that, in fact, this is to be expected.  This seems to me to run counter to Andrew's occasional hints that there is always univocal information.


It's tough.