The soul/spirit - essentially synonyms in all their uses - is a pretty confusing concept for everyone after Descartes. Virtually all the ancients viewed the soul/spirit as a quasi-physical stuff which was the motive force for all living/moving things. Famously Aristotle argued that the heavens were propelled by a divine Soul which contemplated its own perfection since anything less would make it imperfect - and his "heavens" were concentric crystal spheres revolving around the earth, each propelled by lesser Souls and thus in some sense alive.

Plato, in his "Timaeus" dialogue, also filled the World with Soul - itself composed of variously shaped atoms, whirling endlessly around in circular motion. And the supreme goal of a philosopher was to create a similar divine circular motion in his own soul.

Aquinas, in some ways following Aristotle, argued that the soul was the "intelligible Form of the Body" - careful analysis of his argument shows he meant the information pattern of activity. In computer science terms we could call it the program. Living things have various kinds of soul according to Aquinas and Aristotle - what they called the First, Second and Third Entelechies. The first was simple growth, as in plants. The second was sensitive behaviour, as seen in animals. And the third was discursive reason as seen in human beings (and the gods.)

Descartes was a Mechanist, one of a school of thought that all natural processes could be explained in mechanical terms. This included concocting some quite fanciful explanations for things like magnetism - the Mechanists imagined lots of little screw-shaped atoms circulating around magnets in a 'vortex'. The idea of a 'field' was impossible to their literalistic physicalism and more than a few rejected Newton's gravity for that very reason. The Mechanists imagined vortexes of some sort of fluid pushing planets around like hydraulics - akin to hydraulic garden displays which were a fad amongst the rich.

Mechanical animals were something of a fad too, and the main inspiration for Descartes metaphysical distinction between animals and humans. He could imagine mechanised animal behaviour, but not mechanised human equivalent speech and reasoning. And he imagined the 'soul' controlled the body via hydraulic piping in the form of nerves.

But, as robotics has taught us, mechanised life-like behaviour just isn't as easy as 17th Century Mechanics imagined. Programs and robots that work autonomously in real environments are very difficult and far from life-like. The easiest things to emulate with machine intelligence has been formal reasoning - the hardest has been everyday tasks. And we're a long, long way from self-reproduction and self-development - robots will be made, not grown, for a long time yet.

So the mechanical body vs the non-extended soul is something of a furphy, a gross over-simplification by imaginative clock-work makers of the 17th Century. The body - as intelligent matter-in-motion - is more soul-like and less like a simple machine. Because in the end "soul' always meant life-like motion as seen in living things. Sure it's all chemistry and physics, but it's guided by information, thus working quite unlike machines in our macroscopic world.

Thus the whole stupid dichotomy makes two mistakes, not just one.