Idiosyncratic semantic constraints in the grammar result in reference being made using one form instead of another. Logical constraints result in reference not being made at all. Meaning is not merely a reference to concepts in the real world. It depends on linguistic factors in part unique to each individual language; meaning depends not only on the logical combination of real world concepts. The system of language cannot be described only in terms of extra-linguistic logic.
INTRODUCTION TO LINGUISTICS & PHONETICS - SEMANTICS OF WORDS AND SENTENCES