Conceptual Relativity + Dualism + Putnam + Wittgenstein + Kant

Rather characteristically I did not follow through with my planned reading of Ethics Without Ontology last night. I thought I had exhausted Putnam's line of thought on ethics in that book, and I needed to start another project. That project's not applicable here, though.

I was wondering about Putnam's conceptual relativity, which goes something like,

In certain cases what exists may depend on which various conventions we adopt. (39)

which, I assume, is supposed to seem like a ridiculous notion on first sight. It fails to outrage or amaze me. It seems somewhat reminiscent of Kant's transcendental idealism, but with a desultory nod toward Wittgenstein's notion of Lebensform and language-game. Does Putnam's conceptual relativity commit him to object-appearance dualism?

I think it does; and that's not necessarily a bad thing. It seems to me, and this seemed to me a while ago to hold, that Wittgenstein in a way offers an alternative way to derive categories of the understanding, a non-empirical a posteriori method of looking and seeing what's common. Different people may see different aspects or derive different rules from the same situation depending on a variety of conditions: prior training, culture or even native tongue.

Putnam seems just to enunciate to a further degree of explicitness this Wittgenstinian implication. When looking at the duck-rabbit (pictured below), can you say the rabbit exists if you only see a duck? Vice versa? In some way (one that's probably not very mysterious) our category determines the existence of the aspect that we see. In an analogous way, the category of causality, for instance, determines how different object relations appear to us. But whereas Kant sought to legislate our appearances, Wittgenstein actually keeps the human autonomous.

I'll go on further later. Work is picking up.