A Short History of Modern Philosophy: From Descartes to Wittgenstein, Second Edition Read Online Free Page B

that philosophical movement now known as ‘scholasticism’. The greatest luminary of this movement was St Thomas Aquinas (1225-1274), whose Summa Theologica purported to give a complete description of the relation between man and God, relying only on philosophical reasoning, and without recourse to mystical assertion or unsupported faith. His master at every point was Aristotle, and the subsequent synthesis of Christian doctrine and Aristotelian metaphysics—known after its creator as Thomism—has remained to this day the most persuasive of the foundations offered for Christian theology.
    In order to understand subsequent developments in the history of philosophy it is necessary to grasp some of the conceptions, disputes and theories that emerged from the attempt to set neo-Platonic and Aristotelian doctrine into a framework of monotheistic religion, and in the course of doing so to reconcile classical science and morality with the dogmas of faith. Contrary to the opinion of their successors, the medieval philosophers were not merely slaves of authority, nor were they easily deterred from speculations which led them into conflict with Church or State. As the scholastics themselves were given to saying, ‘authority has a nose of wax’, meaning that if you can get hold of it you can bend it as you will. Nevertheless it is undeniable that, looked at as a whole, their philosophy has a conciliatory aspect, upholding through reason doctrines that either coincide with or leave room for the articles of faith. Consequently, if we are to see what is distinctive in the speculations of this period, we must look behind the doctrines to the logical and metaphysical arguments that were used to support them.
    The concept of substance
    The Aristotelian logic, expounded in the works known as the Organon, was preserved in part by Boethius, and later delivered up in full by the scholars of Islam. Fundamental to this logic is the distinction between subject and predicate. Every proposition, it was thought, must consist at least of these two parts, and, corresponding to these parts, reality itself must divide into substance and attribute, the latter being ‘predicated of’ or ‘inherent in’ the former. The distinction has its origins in logic, and in the Aristotelian attempt to classify all the valid ‘syllogisms’ within a single scheme. But it has clear metaphysical implications. Since substances can change in respect of their attributes, they must endure through change. Moreover, if we can refer to substances it must be possible to separate them, at least in thought, from the attributes with which they might at some particular moment be encumbered. Hence we should distinguish the ‘essence’ of a substance—that without which it could not be the particular thing that it is—from its ‘accidents’, the properties in respect of which it might change without ceasing to exist altogether. Finally, it is substances, in the Aristotelian view, which are the ultimate constituents of reality, and our knowledge of the world consists in our various attempts to classify them into genera and species.
    One of the problems that the medievals bequeathed to their seventeenth-century successors was that of whether, and how far, it makes sense to say of a substance that it can cease to exist, or be created. We find that there is an innate tendency in the Aristotelian metaphysic to regard all change as a change in the attributes of a substance. Hence the coming to be or passing away of a substance demands a very special—indeed metaphysical—explanation. For many philosophers influenced by Aristotle, these ‘existence changes’ have no explanation. Later philosophers such as Leibniz went further, arguing that a substance must contain within itself the explanation of all its predicates. In which case it becomes hard to envisage how one substance might create or destroy another, except by a miracle which, in the nature of things, it lies beyond