Return to the claims and Rips’ objection ...
‘object perception reflects basic constraints on the motions of physical bodies …’
(Spelke 1990: 51)
‘A single system of knowledge … appears to underlie object perception and physical reasoning’
(Carey and Spelke 1994: 175)
I think there's something here that should be uncontroversial, and
something that's more controversial.
Rips’ objection (2011, p. 92)
Leslie’s informal report on the Pulfrich double pendulum illusion (which
appears never to have been published) suffices to show that
it was too simple to say that
‘object perception and causal perception are one and the same process’ or to
talk about ‘object perception and physical reasoning’.
But it remains possible that the launching effects are consequences of the
ways that object indexes are assigned and maintained (although this is far
from the only conclusion compatible with the limited available evidence).
Rips: ‘This possibility, though, is not one that advocates of Michotte’s
hypothesis have taken up. The favored view is one in which separate
modules are responsible for descriptions of objects and of their
mechanical interactions, with central mechanisms then resolving potential
conflicts between them.
For example, Leslie (1988) argues that perceptual
modules do not by themselves settle inconsistencies between the spatial
positions of objects and their causal interactions. In certain
illusions, adults tend to perceive solid objects passing through each other
(Leslie cites the Pulfrich double-pendulum illusion; see Wilson &
Robinson, 1986). Thus, the module for object tracking doesn’t prohibit
interpretations of physical events that are causally impossible. Of
course, people realize that such events cannot really be taking place and
are surprised when they perceive them, but that is because they have
principles stored in long-term memory—for example, the principle that two
solid objects cannot be in the same place at the same time—that classify
these events as illusions or anomalies. Leslie’s argument suggests
that people individuate objects and calculate their causal relations by
means of separate mechanisms; thus, we can’t count on causal constraints
being part of the object-tracking module. If Leslie is right, there is
reason to question Butterfill’s (2009) conjecture that ‘object
perception and causal perception are one and the same process’’ (p.