Diderot, Philosopher of Energy

BookDiderot, Philosopher of Energy

Diderot, Philosopher of Energy

The Development of His Concept of Physical Energy, 1745-69

Oxford University Studies in the Enlightenment, 255


January 1st, 1988



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The title of this work may seem to beg an important question, since it rests on the assumption that Diderot has a ‘concept of physical energy’. Indeed the aim of the study is, in part, to assemble evidence in support of the acte de foi implicit in its title. I am using ‘physical energy’ in a loose sense, as a convenient term to denote ‘what matter can do’ as distinct from ‘what matter is made of’. Hence it may be taken as broadly synonymous with ‘power’ or ‘force’, encompassing both active and potential forms, and thus corresponding to a combination of the fourth and fifth senses identified by the Oxford English Dictionary:
4. Power actively and efficiently displayed or exerted. 
5. Power not necessarily manifested in action; ability or capacity to produce an effect.
Modern subatomic physics, of course, recognises no such distinction between ‘being’ and ‘doing’; at a fundamental level, matter-as-substance and matter-as-energy are interchangeable (and, as I shall argue towards the end of the study, Diderot himself comes close to a similar position). Nevertheless, the division is both justifiable and useful within the context of eighteenth-century philosophies of nature. For, as many scholars have pointed out, the trend towards nature as an integrated, active phenomenon, in place of the cartesian view of passive étendue only incidentally endowed with motion, was crucial to the development of scientific thought in the mid-eighteenth century. Debate and development on such issues as Newtonian attraction, inertia, electricity and magnetism, chemical reactions, not only contributed directly to the advancement of physics and chemistry, but also (like cartesian mechanism) impinged upon the perennial biological questions, themselves being investigated from a new and exciting angle. 
As a philosopher rather than a practising scientist, Diderot was ideally placed to draw freely and creatively on all these areas, and his speculations on what we might call ‘the nature of nature’ are highly characteristic of the new approach. He comes increasingly to discuss and define natural phenomena (organic and inorganic alike) from the point of view of nature’s powers – in the spirit of Renaissance naturalism, but from the perspective of up-to-date scientific findings. It is in this sense that I refer to a ‘concept of physical energy’. 
Given the organic quality of Diderot’s thought, it is not surprising to find the idea of energy recurring in other areas of his works. If man is composed of matter – active matter – than all human activity, be it moral, political, aesthetic, becomes capable of interpretation in terms of energy. I share Chouillet’s conviction that this is a crucial aspect of Diderot’s overall philosophy, which deserves to be more widely recognised and more fully understood. 

Table of Contents

Table of Contents
Section TitlePagePrice
Title Page 4
Copyright Page5
1. The metaphysical foundations20
A. Essai sur Ie merite et la vertu (1745)20
B. The Pensées philosophiques (1746)21
i. Deism: the rôle of biology in metaphysics22
ii. Atheism: the rôle of energy in matter23
C. La Promenade du sceptique (1747)28
i. Atheism in the 'Allée des marronniers'29
ii. Oribaze's 'spinozism'30
iii. Symbolic elements31
iv. Diderot's conclusion33
D. Lettre sur les aveugles (1749)34
i. Interim developments34
ii. The letter to Voltaire: monism36
iii. Diderot and Saunderson37
iv. Saunderson's account of natural energy40
2. Transition: from the Lettre sur les aveugles to the Pensées sur l'interprétation de la nature (1749-1753)45
A. Anti-finalism and the autonomy of scientific enquiry45
i. Prospeaus46
ii. Apologie de l'abbé de Prades46
B. Presentation of materialism48
i. Genesis discredited as an alternative to materialism48
ii. The concept of chaos: matter and energy49
C. Investigation of biology53
i. The methodological principle: defence of de Prades53
ii. Spontaneous generation in the Apologie54
iii. The biologically deviant55
iv. Vegetal regeneration: the concept of latency58
v. The philosophy of flux59
D. Diderot and Buffon: the philosophy of life62
i. Definition of the kingdoms of matter: sentience as a criterion63
ii. The concept of gradation66
iii. Inorganic matter67
3. Pensées sur l'interprétation de fa nature70
A. Conjeaures and Questions71
i. From the unity of nature to the unity of energy71
ii. The organisation of matter: attraaion74
iii. Organic matter: its relationship to the inorganic80
iv. Electricity and magnetism84
B. Diderot and Maupertuis87
i. Common rejeaion of previous systems88
ii. Maupertuis's system: Diderot's exposition89
iii. Maupertuis's system: Diderot's interpretation and reformulation94
iv. Postscriptum105
4. Transition: from the Pensées sur l'interprétation de la nature to the Rêve de d'Alembert (1754-1769)108
A. The temptation of vitalism109
i. Letter to Sophie Volland, 15 Oaober 1759109
ii. 'Naître'117
B. Sensibilité127
i. Conceptual relationship between life and sensibilité128
ii. Physical sentience128
C. Sur la cohésion des corps: energy132
i. Attraction as a source of unity132
ii. Attraction as a challenge to unity133
iii. Diderot's interpretation of attraction134
D. Approach to the Rêve de d'Alembert: letter to Duclos, 10 October 1765140
i. Vital energy: sensibilité substituted for life140
ii. Nutritive assimilation: continuity substituted for contiguity141
iii. Organic and inorganic142
iv. Remaining weaknesses143
v. Postscriptum144
5. Le Rêve de d'Alembert146
A. Sensibilité: the basic concept148
i. Sensibilité and energy148
ii. Sensibilité and life150
B. The activation of sensibilité153
i. The non-sentient system154
ii. The sentient system: nutritive assimilation166
iii. The outcome of activation: organic unity169
C. Active sensibilité within the organism179
i. The problem179
ii. Development of sentience within the organism180
iii. Funaion of sentience within the organism182
D. Sensibilité and metaphysics193
i. Logical advantage of sensibilité over spiritual substance193
ii. Elimination of the spiritual by sensibilité194
iii. Avoidance of vitalism and spinozism195
iv. Closing the circle: atheism198