Chris Martin

Peter Abaelard and the Metaphysical Foundations of Logic

The nature of grounding has in the recent discussion of it proved to be rather controversial with a significant number of writers arguing that no sense can be made of the notion. Among those who do accept that a coherent account of grounding can be given and is indeed required if we are to properly understand many peculiarly philosophical forms of argumentation there is nevertheless significant disagreement about what such an account of should look like. In particular there is much debate over what kinds of items the grounding relation relates and just what the logical character of the relation is. The one point that almost all of the proponents of grounding agree on is that it is a non-causal form of determination, where the determinable is said to have the feature of interest, to use the phrase universally said to be characteristic of grounding, in virtue of some feature of the determinant. Where this relationship exists we may, perhaps, explain the features of the determinable as grounded in or by those of the determinant. This relationship is contrasted with that of causation which is in these discussions assumed to be relation between spatio-temporally ordered items such as events. This is quite different to the ancient and mediaeval concept of causation even when we restrict this to efficient causation, since the cause and effect in such causation were held to be simultaneous. It is not surprising, then, that Aristotle’s theory has been invoked as an early recognition of grounding.

An alternative approach to at least the mediaeval history of grounding is, I think, to consider a relation of determination which played a central rôle in the mediaeval theory of argumentation, the notion of a topical warrant, or as we can, and probably should say, a topical ground. A ground that is for the truth of a conditional, the validity of an argument, or of one fact’s being settled, non-causally, by another. This theory has its origins in Boethius’ account of non-syllogistic inference and the leading figure in the development of the theory of the topics in the middle ages is Peter Abaelard. In this paper I set out first to say something about Abaelard’s general metaphysical position and the place that one form of grounding plays in his theory of tropes. I then go on to show how he understands his general account of logic to be grounded in that metaphysics, in a second sense of grounding, by means of indemonstrable topical principles.

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