Les Principes des Choses en Ontologie Medievale (Thomas d'Aquin, Scot, Occam).
The fundamental concepts of Aristotle's metaphysics aim at accounting for the principles and causes of Being. These concepts imply a certain order of knowledge which rests on the ultimate character of Being. Things exhibit a proper nature, a movement, and an end which make them unavailable to manipulation. Yet "is the importance of things as source and term of thought not due to the fullness [plenitude] that Ancient thinking is able to grant them in the absence of creation?" (p. 12). The identification of the primary cause as the Creator entails that things do not owe their Being to themselves. Emptied of their consistency, they reveal Being only by participation or conservation. The road to an empiricist reduction or to a transcendental science is thus opened.
In Aquinas, ontology rules over analogical predication. Analogy aims at preserving the diversity and autonomy of beings whose cause is not so much essence as esse. However, Bastit insists, "the esse is immediately contracted by the essence in the ens of which it is the act. Only by abstraction can it be separated from it" (p. 185). It would thus be a mistake to oppose esse to ens. Res is the measure of ens and the ground of essentia. The author argues that thanks to its hierarchic order and its conception of analogy and casuality, Aquinas's thought avoids the contradictions and reductions of transcendentalism and nominalism.
Scotus makes the ens communis, rather than God, the first object of metaphysics and replaces analogy by univocity. This leads to a new conception of the transcendental: "instead of being defined by its conversion with Being, it will now be defined by its indifference to the finite and the infinite" (p. 71). The connection between existence and essence becomes purely accidental. By opposing to Scotus's determination the empirical reality as an emergence of divine will and power, Ockham's equivocity appears as the reverse of Scotus's univocity. Transcendental terms such as res or ens become mere commodities of language. Since Being designates existing things as well as possible ones, it can be reduced to individual things or to the copula. "In the realm of language the copula expresses the individual being that is also expressed by the action of the subject to which the esse can be reduced. In all this, there are only individuals, the verb `to be' is useless, or rather is merely useful" (p. 200).
Beyond the historical character of Bastit's enterprise lurks a question of primary importance for contemporary philosophers. This book is not only to be recommended to the attention of a few specialists. This is an important work of fundamental ontology; its clarity and depth is urgently needed by contemporary philosophy. --Pascal Massie, Vanderbilt University.