Ampère, André Marie (1775–1836)

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AMPÈRE, ANDRÉ MARIE
(1775–1836)

André Marie Ampère was a French physicist and philosopher; his main achievement in physics was the foundation of electrodynamics. He correctly recognized that Hans Christian Ørsted's discovery, in 1819, of the effect of electric current on a magnetic needle was merely a special case of the general correlation of electricity in motion with the rise of a magnetic field. His explanation of magnetism in terms of molecular electric currents was a bold anticipation of one feature of the later electron theory.

Shortly after Ampère's death his Essai sur la philosophie des sciences appeared with a biographical note by Charles-Augustin Sainte-Beuve and a warm appraisal by Émile Littré. Its subtitle, Exposition analytique de toutes les connaissances humaines, indicated that the main topic was the classification of sciences, in which Ampère was as much interested as his contemporary Auguste Comte. Ampère's main division of sciences into "cosmological" and "noological" was inspired by Cartesian dualism. The details of the classification, which also included "applied sciences"—medicine, agriculture, etc.—are now of only historical interest.

Far more interesting is La philosophie des deux Ampères, edited by J. Barthelémy Saint-Hilaire. The title is misleading because the only contribution of Ampère's son Jean Jacques is an introduction to the philosophy of his father. Besides this, the book contains some unfinished philosophical manuscripts as well as Ampère's letters to Maine de Biran, with whom he remained in personal contact and in correspondence until Maine de Biran's death in 1824. Ampère accepted the central idea of Maine de Biran's voluntaristic idealism that the true nature of the self is revealed in the introspective experience of effort. But unlike Maine de Biran, Ampère more cautiously differentiated what he called emesthèse (that is, consciousness of personal activity) from the sensation of muscular effort that can be induced by some external agency.

This was not the only instance of Ampère's remarkable gift for introspective analysis. In dealing with the association of ideas he distinguished two cases. The first is commémoration, or ordinary recall, when two associated ideas remain unaffected by their contiguity. The second is concrétion, when two ideas merge, for example, when the present perception of an object seen before blends with the recollection of its previous perception. But the main difference between Ampère and Maine de Biran concerned the problem of knowledge of the external world. Maine de Biran, under the influence of Immanuel Kant, denied any possibility of knowing things-in-themselves; Ampère, under the influence of Isaac Newton, John Locke, and his own scientific interests, believed in the possibility of knowing inferentially the relations between things-in-themselves. These "noumenal relations" are similar to Locke's primary qualities; they can be known when the general spatial, temporal, and numerical relations are divorced from the qualitative content (Locke's secondary qualities) of sensory experience. But unlike Locke, Ampère interpreted the impenetrability of matter dynamically, as being a result of inextensive resistances (résistances inétendues ) of which there is an indefinite number in each body. This view of matter as being a product of inextensive dynamic centers is thus closer to the dynamism of Gottfried Wilhelm Leibniz, Roger Joseph Boscovich, and Michael Faraday than to the traditional atomism of Newton. On the other hand, Ampère remained a Newtonian in his insistence on the reality of absolute space and time, which he interpreted theologically, again like Newton, as attributes of God. Equally Newtonian was his rejection of the Cartesian plenum.