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| Georg Ernst Stahl |
Georg Ernst Stahl was a leading German medical scientist and chemist of his day. Stahl was appointed professor of medicine at the University of Halle in 1694, and from 1716 until his death he served as personal physician to Frederick William I of Prussia. His numerous medical writings had a strongly doctrinal tendency, which made them the source of lively, often bitter, controversy.
His famous phlogiston theory, an erroneous explanation of the nature of combustion and calcination, was nonetheless, before Antoine Lavoisier’s discoveries, instrumental in placing chemistry on a scientific basis. The same may be said of his studies concerning the properties and composition of acids, alkalis, and salts.
Led by his medical, rather than chemical, interests to philosophy, Stahl elaborated (particularly in his Theoria Medica Vera, 1707) a rigorous position of animism, affirming that the animal organism was formed, governed, and preserved by an immaterial principle, or soul.
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| Frederick William I of Prussia |
If Stahlian thought was indebted to the archei of J. B. van Helmont’s occultist biology, and more broadly to both neo-Aristotelian and Neoplatonic versions of animism in the late Renaissance, his notion of soul, reflecting the impact of post-Cartesian dualism, was typical of his own period.
He conceived of it as essentially a rational and spiritual substance distinct from matter, but simultaneously he assigned to it the ability to control the organism by an “unconscious” mode of activity. Thus, the soul not only thinks and wills but, having constructed its body, also excites, regulates, and sustains all involuntary and vital processes.
It does so by the intermediary of movement, which Stahl regarded as an immaterial entity, for matter itself is held to be essentially passive and inert. The soul, by a specific energy, is supposed to communicate the “spiritual act” of movement to the organism in pursuance of its own aims.
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| J. B. van Helmont |
This rather obscure view of things (which Gottfried Wilhelm Leibniz, among others, criticized) was not improved by Stahl’s manner of expression, a mixture of dogmatic haughtiness and repetitious turgidity. If he failed,moreover, to consider properly the various contradictions and difficulties peculiar to his position, this was due largely to his lack of interest in metaphysics as such.
His animism was intended less as a philosophical contribution than as a theoretical standpoint from which to perceive and evaluate the phenomena of disease and health in accordance with an expectative approach to therapeutics.
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| chemical reactions |
Even more significantly, it represented a protest against the dominant iatromechanist and iatrochemical schools, which at the time tended to see animate beings too naively and rigidly in terms of facile mechanical analogies and unexplained chemical reactions.
But although Stahl’s animism had the merit of emphasizing the presence of an irreducible “life force” having no equivalent in the machine, the omnipresent role allowed to this life force at the expense of a purely organic dynamism proved untenable.
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| Gottfried Wilhelm Leibniz |
The influence of Stahlianism was checked during the first half of the eighteenth century by the success of the mechanistic and empirical doctrines of Hermann Boerhaave and Friedrich Hoffmann.
Subsequently, Stahl’s medical philosophy was reinterpreted at the important Faculty of Montpellier, with the general result that its spiritualist aspect was abandoned as unscientific while its insistence on a metamechanical “vital principle” in the organism was adopted as profoundly valid. Stahl thereby came to be recognized as the founder of the vitalistic school of modern biology.
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| spiritualist aspect |
