“The crucial difference between them is that Wierenga makes presentness a feature of the individual essence of every moment of time. Wierenga’s analysis thus entails the metaphysical doctrine of presentism, according to which the only time that exists is the present time. According to presentism, future times do not yet exist and past times no longer exist. Therefore there literally are no times that have the property of pastness or futurity. When a time becomes past, it does not exchange the property of presentness for the property of pastness; rather it just ceases to exist altogether. Times exist when and only when they are present. They come into existence successively and are present just as long as they exist. No time exists which is not present.”