Instead of ranking collections of truths by two measures, strength and simplicity, we will rank them by three, strength, simplicity and fit. A collection of truths that entails that what does happen has (at earlier times) a higher chance of happening has better fit than a collection that entails that what happens had a lower chance of happening. The laws are those generalisations in the collection of truths that do the best by these three measures of strength, simplicity and fit. The collection