The soul is a phrase sometimes used by philosophers when they are outlining the ontology, or being, of the human mind. Its straightforward meaning is to refer collectively to the faculties of the mind often including memory, imagination and reason, though these do vary. But in addition to this descriptive meaning there also appears to be a more emotional sense to the word. Soul is used rarely and almost exclusively in the context of just one of these faculties, the imagination. Perhaps the emotive aspect is because the imagination uses different processes from reason, namely associative rather than logical ones, and this offers a strange dilemma to the science of philosophy which always treats reason as its supreme principle. As we move onto six accounts of the soul it will be seen that engines offer a good fit for some of the processes of the mind especially those of the imagination. Put simply this is because the soul with its various faculties can be thought of as containing a substance, rather as an engine with its different chambers may contain a fuel, and it is through the modification of this substance by external perceptions that consciousness may arise in some way. In some accounts of the soul this substance is comprised of individual ideas or appearances that are the residue of experiences of the world, whilst in others the ideas are more abstract having already undergone some degree of processing. A final explanation for the use of engine analogies follows from my own experience of briefly running an automobile workshop, through chance circumstances, many years ago. This has left me with a keen eye for certain similarities between some of the repetitive processes in engines and some of those of the human soul.

Hume’s Soul

David Hume was a Scottish philosopher who as a precocious youth wrote A Treatise of Human Nature in 1738. It would fall “dead born from the press”. The writer, after a breakdown, would then re-establish himself as a famous historian and rewrite his Treatise in a much shorter but also less radical form. In the earlier work the emphasis is much more on ideas. This was radical at the time because the ideas were treated as though they were entities in their own right seeking interactions with other ideas of a similar ilk. Essentially the ideas are copies of the world that become linked to each other through similarity or being circumstantially related in space and time. Such ideas then form strong interactions with each other. Consciousness is simply the passing from one idea to the next in a region of the soul called the imagination. In consequence the pattern of these ideas, as they are triggered, creates a burst of consciousness that actually starts to shape the very world these ideas have originated from. We believe a match will light because the idea of flame has fused strongly with the idea of striking. This general phenomenon Hume called habit or custom and its implication is we not only learn from the past but are actively shaped by it in the present and in turn start to shape the world around us to conform with these habits. In summary then his thesis is that an impression, or perception, triggers a chain of ideas and we experience these as flashes of consciousness. Furthermore, the meaning or signification of a particular stimulus is nothing other than the related ideas that, through habit, repeatedly spring to mind, one after the other, in the brief instant following the stimulus. We associate heat with a flame through their constant conjunction and our consciousness flows imperceptibly between those two ideas. Self-consciousness, which has to be the supreme principle of the soul, is not clearly distinguished from mere consciousness for Hume. However, he does in one instance describe the movement of an individual’s disposition from one idea to the next wherein attention pauses for longer on familiar ideas and their relationships whilst flitting much more rapidly between less familiar ideas. The implication of this, is that consciousness moves through habit along well worn tracks offering if not a sense of personal identity through the ideas themselves, at least a fairly stable and unique viewpoint of the relations between these ideas as they come to mind. An ontology of Hume’s soul therefore consists of the fairly minimal content of habit and the repeated movement of its disposition along various channels guided by these habits, captured beautifully by Hume’s phrase that the vividness of a conception diffuses to its related ideas “as though conveyed by so many pipes or canals”. Finally now in consideration of the engine analogy itself, not only have I used the example of a lighting match to characterise some particular ideas in Hume’s soul, but I have explained how the ideas themselves appear to trigger other ideas in much the same way as combustion might spread from a spark through the entirety of a flammable mixture. The resulting effect is to force down the cylinder and turn the crank. For Hume, meanwhile, it is a similar chain-like process in the imagination that can bring sufficient pressure to bear upon the will resulting perhaps in action. Reason, which is normally a primary faculty for philosophers, plays only an assisting role for the imagination in Hume’s account here.

Kant’s soul

Immanuel Kant was a German philosopher who spent nearly his entire life as an academic in a small town called Konnigsberg. Famously he declared one day that Hume had woken him from his academic slumbers. As an expert in logic, Kant would go on to create a curious hybrid of Imagination similar to that envisaged by Hume, but at the same time overseen by a new faculty of his own invention called apperception. Essentially this was a faculty of government which applied laws to the ideas to determine how they should coalesce and relate to each other, much like the laws that govern individual people in society. Kant was troubled by the type of fragmented consciousness he believed would result from Hume’s ideas arbitrarily triggering other ideas in the Imagination. He did not believe that this matched up to his own experience of a coherent consciousness wherein he could say “this is who I am”. He felt he was more than merely a product of the ideas that he had acquired. For Hume the word “dog” would trigger ideas of particular dogs all with dog-like properties and create an association of ideas that, using a critical turn of phrase, would swarm across the soul. Instead Kant believed that these copies of the world, which he chose to call appearances rather than ideas, should be considered to be grouped together in a synthesis and unified. This creates what he calls a schema and is essentially an abstract idea or concept. The schema of a dog, which Kant actually describes as being in the recesses of the human soul, is a sort of template that would enable someone to recognise a dog. But more strikingly the schema is credited with going well beyond this remit since it carries with it certain laws about how all its members should appear. A dog that is present, for example, to Kant’s soul, would only appear with properties that belong to a particular chosen schema rather than the fleeting impressions of the object itself. Thus the actual dog would be unknowable, though inducing the appearance of a familiar and coherent animal. Furthermore a patch above its left eye would appear as a result of the many intuitions assembled over time, both from this dog and indeed from many others, rather than from an immediate perception, perhaps as a statistician might smooth out data using a four-point moving average. Of course, this coherence can suddenly be shattered but Kant writes little of the effect of objects breaking the laws to which they had hitherto been bound, only commenting that confusion would ensue. For Kant’s soul, the ultimate objective though, is self-consciousness and this arises from the various manipulations that it successfully imposes upon the external world, using three related faculties or regions of the soul. First, intuition collects various fragmented appearances from the world before imagination then creates sequences by collecting yet more copies of appearances from memory, all the while placing these in time-order, like images on a film strip. Finally apperception unifies these into a single experience. In this respect, apperception may be thought of as being a bit like a film projector since it creates a coherent experience by applying laws or categories to the images rather as a projector creates a coherent moving image by applying its juddering mechanisms to the strip of film. In Kant’s system, the fragmented appearances can only produce a weak sense of consciousness which he calls inner-sense. Already matching up to Hume’s consciousness based on ideas, though, he claims this inner-sense is superseded by a far more potent sense of self that derives from apperception. This is the aforementioned process that produced the schemas, but there is also an additional effect of apperception that is critical here. It is a process that produces a subject’s sense of who they are or their identity. By a slight of hand, then, Kant has bound our experience of the world to our experience of ourselves. We cannot even think of the world, therefore, without observing a world governed by the rules of nature that we have already imposed upon it. We are free to dream as it were, but not free to know. With this final step of outlining the origins, domain and validity of thought, Kant believes he lands a decisive blow upon Hume’s system, one that he was always trying to supersede. Finally to represent Kant’s soul with an engine it would best be modelled by a device that actually transforms its environment in some way and for this analogy I will chose an electric motor. The motor itself is regulated by a commutator that ensures various electromagnetic forces within its windings of wire be united into continuous rotation. This is achieved by constant switching round of the power supply on every half turn, effectively allowing the motor to take in whatever flow of current is conducive to it maintaining its continuous rotation. Without the unity afforded by this commutator the motor simply won’t turn and perhaps in a similar vein, Kant has claimed that without the unity afforded by his newly discovered faculty of apperception, a human soul simply won’t think. New faculties are extremely rare in philosophy and much of Kant’s Critique of Pure Reason is taken up justifying why apperception should exist at all given that two thousand years of philosophy since the Greeks had failed to spot its relevance. The conclusion then would be an entire system in which we mould are own experiences through our own laws and regulations in a shift matched only in magnitude to that effected by Copernicus in his re-evaluation of planetary orbits. But in a final twist of brilliance Kant was able to use his system to explain that if we speculate on matters beyond experience we would no longer have the contents of imagination to guide our reasoning, just as if the mechanic were to speculate on the forces that drive the motor, rather than getting on with the task of simply checking whether the motor actually works. This malignant and ultimately futile form of enquiry Kant called dialectical investigation.

Proust’s soul

Marcel Proust is known for writing an incredibly detailed account of the thoughts and experiences of a character supposedly resembling his younger self. Usually contained in three thick volumes, it is often found on book shelves though seldom read. I read my father’s volumes plucking them almost by chance from his heavily laden shelves. My first discovery was that the characters were quite mean to each other rather as I and my friends had been. But there was also a philosophical dimension that we also shared wherein reflection would allow us to forgive each other for our momentary acts of cruelty. For Proust this was an authentic part of human nature, along with jealousy and unrequited love, all things I had felt keenly myself. The young Marcel, the character in the novel, having experienced all of these things including the withheld kiss from his mother at bedtime, becomes a philosopher and beyond that wishes to write the novel of his own life. One thing stands in his way however, which is his inability to turn his experiences into meaningful prose. Then through the discovery of a new kind of involuntary memory upon the taste of a madeleine soaked in lime tea, he embarks on a new analysis of his past brought to life through a present sensation and those memories of events that had been affected by like-sensations in the past. The riddle of Proust is whether the transcendental effect of such memories as a vehicle for making art is a real potential for all of us or whether they are just the plot of the novel and genius actually lies deeper in the structure of the novel itself. I can’t pretend to know the answer to this, though I see the metaphor laden sentences that make up the novel as being a bit like the densely associative structures of Hume’s ideas and that what we would be reading therefore is not the outpourings of the soul in flowery prose, but rather the creation of a soul from perceptions already undergoing the associations of ideas as they enter the young hero’s consciousness. On this reading Proust was a philosopher and as Julia Kristeva revealed in her brilliant analysis of the texts that lie behind the novel, he not only studied philosophy but appeared to develop ideas that would go on to be influential in 20th century structuralism and post-modernism. The engine depicted has little to recommend it since it has merely a few chambers and pipes connecting each. The suggestion behind it is that some retained fluid in one chamber may be released almost by chance into another chamber imparting some additional force in the process, rather as memories of the past when encountered unexpectedly may affect the present all the more strongly. Some of the citroens my father worked on were known for having hydraulic systems involving bulbs and pipes which would allow the car to lift itself up once the engine had started and perhaps there is a connection with the workshop in this respect. But rather like the novel itself, maybe these connections to the past are more evocative when their relation to the present remains less clear and enigmatic.

Plato’s soul

The enduring image given to us by Plato is the cave where people trapped with chains see upon its interior surface only shadows of objects and silhouettes. The part that related to my own soul most clearly however was the description of the incontinent man, though not in the present usage of the word thankfully but rather in the Greek sense. The word meant being unable to stick to a resolve that represented the best interests for an individual as a result of the interposition of their more base desires. This reminded me of my constant battles to stop smoking. Such incidents of conflict were ultimately productive for Plato since they revealed the substrata of the mind through its small malfunctions, rather as an earthquake may be put to good use by the seismologist to reveal the layers that make up the inner structures of our own planet. Then ultimately through these investigations Plato would discover the three distinct parts that would make up his soul and their inclinations towards reason, appetite and spirit. The motor chosen is simply one I remember seeing at the science museum as a youngster, when the building was punctuated with the visceral boom of the extraordinary, million volt, spark-machine. Sounding hourly after having charged up its massive capacitors, it would enliven all the exhibits within earshot, including the one depicted here, in the process.

Leibniz’s soul

Gottfried Wilhelm Leibniz’s was a 17th century philosopher and mathematician who combined the two areas of his expertise into an all-encompassing model of the universe. The key to his philosophy was information and how it was made accessible to a type of individual that Leibniz called a monad. The most developed form of this entity was a soul, which could perceive the world immediately around itself as well as reflect upon divine matters and morality. Despite this apparent freedom, however, it was constrained to operate within a harmony set up by God. At first sight the information needed for each monad, with assigned body, to perform a lifetime of choreographed movements was infinite. Yet there are hints that mathematics played a role in this philosophy. Certain numbers that interested Leibniz are curious in that they contain an infinite amount of information if their digits are remembered sequentially yet contain very little information if the calculation which gives rise to them is known. Such a number for example, is pi made by the division of the circumference of a circle by its diameter. Leibniz’s own study of these numbers in the field of mathematics suggested that they may have informed his representation of the universe giving a sort of digitalised experience that was infinitely complex from the viewpoints of the monads yet simple from the viewpoint of the divine creator who performed each calculation needed to generate the digits for the monads to move to. I would need an engine for this representation altogether different from those chosen thus far in this piece, one that was both sealed and had no moving parts. As a student I worked at Harwell, a nuclear research establishment. Its three nuclear reactors with domed roofs were clearly visible from the entrance, and each day I would drive into the compound in my blue Citroen 2CV past the armed guards and barbed wire fences. The reactors were filled with a radioactive substance called uranium and housed a chain reaction that released energy and produced new materials used for medicine and nuclear research. The reactor was similar to Leibniz’s soul in that it was a sealed container. But there was a further similarity too since each vessel had a carefully mediated relation to the outside world. For the reactor this was through control rods that could be lowered or raised to regulate the reaction, whilst for the monad this was through sensory organs that could receive seasoned perceptions to augment the barely distinguishable information already stamped upon it.

Schopenhauer’s soul

Arthur Schopenhauer’s famous work The World as Will and Idea is essentially a fusion of Kant’s and Plato’s ideas combined with Indian philosophy, but all aligned to an important early work of his own called The Fourfold Root of Sufficient Reason. He had presented this as his doctoral thesis. This early work describes how all phenomena, be they the physics of objects or the motivations of thought, must be related to each other through cause and effect. Like Kant, he did not believe objects in themselves needed to be related in this way, but rather for a human to have consciousness that was clear and unified, the appearances of the objects needed to fit together as though they were related. As my time in the workshop drew to an end I would sometimes fit new chassis to Citroen 2CVs when their rusted metal plate could barely hold together any longer. Perhaps the analogy is overambitious here, but in a similar way Schopenhauer can be seen as stripping away Kant’s apperceptive faculty that orders the imagination and then replacing it with a new structure of his own. There are two key differences for Schopenhauer’s soul, however, though both controversial. The first is he believed awareness of our own bodies put us in touch with a fundamental force called the will. This is a primitive force that drives the individual to flourish in the world, though with no specific aim of its own. The second exception is that this will is in fact observable in some phenomena such as in beauty and even as forces of nature such as gravity. For Schopenhauer these definitive experiences of the world are akin to mental archetypes, instantly recognisable and presented as a reality by the countless examples offered up by perception. These archetypes Schopenhauer likened to Plato’s own mental archetypes called forms. The engine shown is a jet engine of which I have no direct experience I hasten to say. The principle illustrated is that of force, simply the constant force of an expanding gas against the internal structure of an engine, harnessed to provide a forwards thrust. This is the principle of the Will. It is fixed as an absolute entity, as are all forces, but is just a phenomenon in the circumstances of its appearance, sometimes visible and sometimes not.