The argument from degrees or the degrees of perfection argument is an argument for the existence of God first proposed by mediaeval Roman Catholic theologian Thomas Aquinas as one of the five ways to philosophically argue in favour of God's existence in his Summa Theologica. It is based on ontological and theological notions of perfection. Contemporary Thomist scholars are often in disagreement on the metaphysical justification for this proof.
Aquinas's original formulation
The fourth proof arises from the degrees that are found in things. For there is found a greater and a less degree of goodness, truth, nobility, and the like. But more or less are terms spoken of various things as they approach in diverse ways toward something that is the greatest, just as in the case of hotter (more hot) that approaches nearer the greatest heat. There exists therefore something that is the truest, and best, and most noble, and in consequence, the greatest being. For what are the greatest truths are the greatest beings, as is said in the Metaphysics Bk. II. 2. What moreover is the greatest in its way, in another way is the cause of all things of its own kind (or genus); thus fire, which is the greatest heat, is the cause of all heat, as is said in the same book (cf. Plato and Aristotle). Therefore there exists something that is the cause of the existence of all things and of the goodness and of every perfection whatsoever—and this we call God.
A syllogistic form collected by Robert J. Schihl follows:
- Objects have properties to greater or lesser extents.
- If an object has a property to a lesser extent, then there exists some other object that has the property to the maximum possible degree.
- So there is an entity that has all properties to the maximum possible degree.
- Hence God exists.
A common argument is that it is not evident that simply because we can conceive of an object with some property in a greater degree, that such an object exists. However, as the argument from degree is built upon principles deemed metaphysically necessary by mediaeval philosophers, this objection might be said to beg the question against Aquinas's framework.
- Blackburn, Simon. "Degrees of perfection argument". Oxford Dictionary of Philosophy. Oxford University Press. ISBN 0-19-283134-8.
- Medieval Sourcebook: Aquinas: Proof of the Existence of God
- Aquinas'/Anselm's Arguments in Syllogistic Form