摘要
The idea that approximate exactness is the most we can and should expect scientific theories to yield underlies the formation and application of the multi-valued logic of approximation discussed in this paper. In this logic, inexactness （measured by truth values） is controlled and minimized by means of uniquely designed deductions. We show how the notion of equality （including substitution of equals） is handled within this logic and we apply it to certain principles and interpretations of quantum theory.
