Galit W. Sassoon ([year]) uses fuzzy logic for complex sentences and comparisons, because they can "associate complex predicates (e.g. negated, conjunctive and disjunctive ones) with graded structures (say, a mapping of entities to numerical degrees)" (127). She states that, in comparisons, the difference between the truth values of two different entities must be > 0, as in x is more than y, or ≥ 0 in sentences like x as y (124-125).
The most interesting part of her paper are the comparisons: you can compare things in logic by assuming that, if v(p) – v(q) > 0 for a sentence p is more than q, the sentence is true. I realized that this formula only works properly with fuzzy logic, classic boolean logic does not work …show more content…
She gives the following example: Danny and Moshe are both 195 cm tall, Moshe however weighs 300 kg more: Sassoon realized that people refused to say that Moshe is more fat and tall than Danny (and vice versa) (142). I assume this is because it is true that Moshe is fatter than Danny, but it is not true that she is taller than Danny, so more p (fatter) is true but more q (taller) is not true. In fuzzy logic, it would most probably be true: assume, the tallness of Danny and Moshe is both to 0.9 degrees true, the fatness is true for Moshe for 0.9 degrees, while Danny's fatness is true to 0.2 degrees; in fuzzy logic, Danny is tall and fat to 0.9 ∧ 0.2 = min(0.9, 0.2) = 0.2 degrees, while Moshe is tall and fat to 0.9 ∧ 0.9 = min(0.9, 0.9) = 0.9 degrees, and obviously 0.9 – 0.2 > 0. But what if the degrees of fatness are both higher than the degree of tallness? Let's illustrate this at the example with the cars: let's say, the black car and the white car are both big to a degree of 0.6, the black car is clean to a degree of 0.8, and the white car is clean to a degree of 0.7, then the black car is big and clean to a degree of 0.6 ∧ 0.8 = min(0.6, 0.8) = 0.6, and the white car is big and clean to a degree of 0.6 ∧ 0.7 = min(0.6, 0.7) = 0.6: my car is bigger and cleaner is false, because 0.6 – 0.6 ≯ 0. In fact, in this case it would be true that the black …show more content…
What is the natural meaning of the black car is bigger or cleaner than your car? Either bigger or cleaner, but not both? Or does intuition also allow for both bigger and cleaner, even although you say bigger of cleaner instead of bigger and cleaner, that is, is or in natural language inclusive, like it is in logic, or is it rather exclusive? The problem is similar to and: as and requires both variables to be true, or requires at least one variable to be true, so, for example, for the black car is bigger or cleaner than the white car to be true, the black car has to be either bigger than the white car or the black car is cleaner than the white car, or both. For more information about this see Sassoon