The concept of the vital force (‘dynamis’) is defined by Dr Samuel Hahnemann (1755-1843) as that aspect of a healthy organism which retains all parts in a harmonious relationship to each other.  Disturbance of this aspect causes illness, and its absence death. He maintained that it was a real material force, like gravity or magnetism, rather than a wholly separate mystical entity,  and he regarded it as an integral part of the organism with no independent existence:
The organism is indeed the material instrument of the life, but it is not conceivable without the animation imparted to it by the instinctively perceiving and regulating dynamis, just as the vital force is not conceivable without the organism, consequently the two together constitute a unity, although in thought our mind separates this unity into two distinct conceptions for the sake of easy comprehension. 
Further evidence of Hahnemann's belief in the inseparability of the body and the vital force is shown by his choice of a word for it which is used in German as ‘vitality’ is used in English.
The significance of Hahnemann’s position is noted by biographers , and explained by the debate in Britain in the years 1814 to 1819 between John Abernethy and William Lawrence.  Abernethy (a vitalist) regarded the vital force as a “superadded” aspect of living things that did not arise from the matter from which they were made. This position defended the theological idea of the soul and the political idea of people requiring external control. Lawrence (a materialist) considered that the “vital properties” arose necessarily from the organisation of matter in living things, a position which defended atheism and republicanism. For the religious Hahnemann to support the latter position but combine it with aspects of the former one is just one example of how his scientific rigour surmounted contemporary religious prejudice.
Lawrence was ultimately forced to deny his views, and this helps to explain why orthodox medicine still has an approach to the body oriented almost entirely on chemistry, with vitality seen as a purely mystical concept. As a result it still has no satisfactory explanation of how our cells know they are part of a single organism, or of what precisely changes when a living creature dies. With the development of physics, Hahnemann’s position becomes much easier to accept, but biophysics is still a field much less well developed than biochemistry.
Homeopathy is oriented on the idea that the primary unifying aspect of the living organism is in the realm of physics without this aspect being at all divorced from the organism’s existence as matter. As a result it is not surprising that the process of potentisation involves a similar shift of perspective from a view of substances based on chemistry to one also based on physics. At the same time the modern understanding of chemical properties depends on learning about atomic and sub-atomic structures and relationships of forces. In this respect homeopathy was a therapy far ahead of its time which maintained (and still maintains) a consistent approach to its understanding of health, disease, life and medical intervention.
1. Samuel Hahnemann (trans. William Boericke), Organon of Medicine, 6th edn, manuscript completed 1841, 1st English edn 1921 (Calcutta: Roy Publishing House, repr. edn 1972), § 9 p. 95.
2. Samuel Hahnemann (trans. William Boericke), Organon of Medicine, 6th edn, manuscript completed 1841, 1st English edn 1921 (Calcutta: Roy Publishing House, repr. edn 1972), §§ 10-11 p. 95-98 and footnote.
3. Samuel Hahnemann (trans. William Boericke), Organon of Medicine, 6th edn, manuscript completed 1841, 1st English edn 1921 (Calcutta: Roy Publishing House, repr. edn 1972), § 15 p. 100.
4. Rima Handley, In Search of the Later Hahnemann (Beaconsfield: Beaconsfield Publishers, 1997), p. 8.
5. Sharon Ruston, Shelley and Vitality (Basingstoke & New York: Palgrave Macmillan, 2005), Chapter 1.
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