Language

In responding to Donald Davidson's confounding of language and conceptual schemes P. M. S. Hacker writes:

"[I]n the metaphorical sense in which a conceptual scheme is said to 'confront reality', it is not a language … but rather the grammar of the language, construed as the rules for the use of expressions that determine what does and what does not make sense.  For it is the grammar of a language thus construed which determines what is logically possible, i.e., what makes sense.  Grammar fixes the 'logical space' which the world (or reality) may or may not occupy.  And assertions couched in the language with that grammar are true or false according to whether things are as they are asserted to be." [Hacker, "On Davidson's Idea of a Conceptual Scheme," p. 298]

The constraints that a language exerts on a "system of generalizations" are constraints on what can be expressed, or more easily expressed, with that language.  These syntactic constraints are to a system of generalizations what the physical constraints of the piece of paper are to a Venn diagram.  One language, or diagrammatic medium, may be more amiable to one conceptual scheme than another, but, in either case, these syntactical constraints are generally taken as being part of the diagram's semantic nature and consistency.