Abstract

Many years ago, when Michael was lecturing in Oxford on the Philosophy of Physics and was trying to explain the logic of Aspect's experiments in Paris, he turned to me to expound the correct doctrine of counter-factual truth. I was flummoxed. It had been much discussed in late- and postmediaeval times, especially in the Iberian peninsula, and had recently enjoyed a revival in the Eastern United States. But Middle Knowledge, as the Schoolmen called it, was beyond my comprehension, and I could only exemplify once again the truism that philosophers were better at raising problems than resolving them.