..Referring to the example given, consider a different arrangement of blocks, where c is on the top of d, while a and b together form a separate stack standing on the table (Fig. 4). The corresponding structure would be different from the previous one, generating therefore a different conceptualization. Of course there is nothing wrong in such a view, if one is only interested in isolated snapshots of the block world. But the meanings of the terms used to denote the relevant relations are still the same, since they are invariant with respect to the possible configurations of blocks. In fact, in the metalanguage adopted in their book, Genesereth and Nilsson would use the same terms (on, above, clear, table) to denote the new conceptualization. We prefer to say in this case that the states of affairs are different, but the conceptualization is the same. The structure proposed by Genesereth and Nilsson seems to be more apt to represent a state of affairs rather than a conceptualization. [...] In order to capture such intuitions, the linguistic terms we have used to denote the relevant relations cannot be thought of as mere comments, informal extra-information. Rather, the formal structure used for a conceptualization should somehow account for their meaning. As the logico-philosophical literature teaches us, such a meaning cannot coincide with an extensional relation. Sticking to a set-theoretical framework, a standard way to approximate such meaning is to conceive it as an intension (intensional relation), taking inspiration from Montague semantics. This means that a single extensional relation is always relative to a possible world. [...] According to this intensional interpretation, a conceptualization accounts for the intended meanings of the terms used to denote the relevant relations. Such meanings are supposed to remain the same if the actual extensions of the relations change due to different states of affairs.