One of the first to challenge this perspective was Georg Ernst Stahl (1659-1734). Living beings, including humans, have a purposiveness which cannot be derived from mere physical-chemical processes. For Stahl, the anima or soul provides what he regarded as the key element of movement to matter within the living body (motus tonicus vitalis). However limited this concept may have been by the understanding of mechanics and physiology at the time, Stahl’s dualistic notion was different from Descartes, in that he differentiated organic life from the inorganic, not the soul from the body. Unlike Descartes, the soul and body were not separate but integrated in the organism. Stahl originated an organismic perspective in the life and human sciences. I have several times (eg. see previous post) emphasised how critical psychiatry integrates mind and brain. It is not Cartesian. This perspective formed the basis for Stahl having an emphasis on psychosomatic medicine, and a focus on clinical medicine rather than the physical sciences.
Yet, Stahl took a mistakenly conceived vitalist position that reductionists deride as much as Cartesianism. Vitalism is the claim that living things possess something else - a vital entity - that is neither physical or chemical in nature. In fact, Stahl's anima was a force within the body, an explanatory agent within physiology, rather than a religious transcendent soul. But, still, Stahl conceptualised the soul as an immaterial ordering principle of movement. Despite this erroneous element in Stahl's thinking, we do need to build on his organismic perspective.
Those that suggest that life cannot be explained in mechanical terms, as Stahl did and I do (eg. see previous post), may seem to be open to the charge of vitalism. But I'm not anti-physicalist. Biological wholes do not literally cause their parts. Nor am I suggesting that living matter has a level of organisation above the physicochemical level that makes it different ontologically. Biological processes do not have causes (such as a vital entity) outside of physicochemical terms.
Neither am I saying that living processes cannot be studied mechanically. The mechanistic conception of nature, however, fails to provide a complete characterisation of living systems (see previous post). Understanding the meaning of human action is a different kind of explanation from mechanical explanation. We explain the parts of biological wholes in functional not structural terms. Non-organic mental illness, for example, is a functional disorder and cannot be explained structurally as brain pathology (eg. see previous post)
Reductionists of course do appreciate there is a mind-body philosophical problem (eg. see previous post). They think, though, that this problem will eventually be solved (see previous post). I take the same view as Kant that the irreducibility of biology to physics is permanent. Our knowledge is limited. We conceptualise organic matter in a different way to inorganic matter. Our understanding is discursive and how living wholes cause their parts is unknowable to us. In fact, it's the discursive nature of our understanding that creates the possibility of mental illness (eg. see previous post). Summarising Kant's Critique of Judgement, we can never have theoretical knowledge that anything in nature is teleological, but such judgment is nonetheless necessary and beneficial for us. We have to accept this enigma to practise psychiatry (eg. see previous post).