Putnam also points out that there is a tension between Goodman’s notion of worldmaking and his first line of thought that leads to his irrealism: the idea that there are conflicting statements in different adequate world versions. As Putnam argues, to say that a statement of one world version is incompatible with that of another (such that a single world cannot accommodate both versions) requires that the expressions in the two versions have the same meaning. However, it is not clear that our ordinary notion of meaning allows such inter-version comparison of sameness of meaning (a thought that Goodman should be sympathetic to, since he already doubts an intra-version notion of that kind). Moreover, there might be better ways to compare alternative versions (e.g., by way of homomorphism-relations between versions, as developed by Goodman in SA and discussed above in 4.1) and to explain how versions relate despite their apparent incompatibility (for example, by paying attention to the practice of scientists who manage to move from one version to another).