Mr. Christian Wolff's opinion on the essence of soul and spirit in general; and Dr. Andreas Rüdiger's opposing opinion (1727)

We could say that Neoplatonists like Proclus and Simplicius with their studies of Plato and Aristotle were the latest possible point at which the use of commentary as a philosophical tool was introduced. During the Middle Ages the success of commentaries was obvious and one could even say that the modern indiscriminate use of references in articles resembles a form of commentary.

We have already seen a philosophical commentary, in which Lange presented a number of passages ripped out of their context from Wolff's writings and then criticized what he thought was meant in those passages. A more faithful reading of Wolff is presented by Andreas Rüdiger, a follower of Christian Thomasius we have met a few times before, in his work Herrn Christian Wolffens Meinung von dem Wesen der Seele und eines Geistes überhaupt: und D. Andreas Rüdigers Gegen-Meinung. Rüdiger gives his reader not just isolated passages, but a whole text of Wolff's rational psychology from the German metaphysics, and leaves his own opinions to a preface and footnotes.

As the name of the work belies, Rüdiger belongs to Wolff's critics, not to his followers. Some of what Rüdiger has to say is clearly based on confusions already dealt by Wolff. For instance, when Rüdiger complains that regarding soul as consisting of a mere force of representing the world would deprive it of all the complexity of its characteristics, such as freedom of its will, we could just point out to Wolff's answer that the force of representation is not meant to be all of what soul is, but only a convenient point from which to deduce all the characteristics of soul.

This does not mean that Rüdiger's criticism is wholly based on confusion. For instance, Rüdiger asks how Wolff can suppose there's an essential difference between souls of humans and of animals, when the difference is based on nothing more than the degree of clarity in their representations. Indeed, he continues, we cannot even say in earnest that animals have less clear experience of things, when their sensory apparatus is sometimes far subtler than ours.

What is probably the most crucial point is the already discussed uneasy synthesis of the notions of the pre-established harmony and the freedom of will. The pre-established harmony is explained by pointing out that even two clocks can show same time without any causal interference, but the problem is how a free agent and a deterministic mechanism could follow the exactly same course of actions. Yes, neither of these series is necessary, but still in one series the later events are determined by the previous events. The problem is exaggerated by Wolff's suggestion that in soul all events are grounded on previous events, just like in the material world: how could one not think of Wolffian soul as a sort of automaton after this?

The problem lies, as Rüdiger points out, in Wolff's notion of ground that combines quite distinct types of relations. Material causes are grounds, but so are human motives (Rüdiger adds animal movements as a group distinct from these two). True, causes and motives do share some characteristics, but they appear to have also crucial differences: cause produces always certain effect necessarily, while motive requires still the will of a person to become reality, that is, while there is not motiveless action, motive does not necessarily lead to action. This distinction is one that Wolff himself noted and he has made it quite clear that he believes in human freedom in choosing what motive to follow. Furthermore, his willingness to distance himself from the pre-established harmony might show a certain skepticism of this theory.

What is remarkable in Rüdiger's book is his willingness to actually suggest an alternative solution to the problem of soul/body-interaction, while earlier critics had just expressed their faith on the possibility of said interaction. Rüdiger notes, firstly, that the matter/soul-distinction can be understood in two separate ways. Firstly, there is the Aristotelian distinction between matter and form, where soul is stated to be one type of form. Aristotelian matter, Rüdiger says, means just substrate (that which is) of a form, which then is the force or activity of the matter (what it does) – thus, form or soul of a living thing consists just of living and its other essential activities. Clearly, such a soul cannot exist without corresponding matter or substrate, and the distinction is more conceptual than ontological.

Still, this does not mean that we could not separate an independent spiritual substance from an independent material substance, and this is what e.g. Descartes did – there is an entity, Descartes said, that is conscious of itself and its own body and various other things, but is still separable from the spatial body. What Rüdiger finds troubling is the identification of spatiality as the distinct characteristic of material substances. Instead, he claims that all created substances must occupy space – and this he thinks is the key to the problem of soul/body-interaction. Soul is not antispatial, but occupies space and even has extension, even if it doesn't act like material substance and exclude other entities from a certain place: thus, a body and a soul can share the same space and also interact with one another, even if this interaction is not like interaction of material substances. What Rüdiger has in mind is then a sort of astral body floating around the crass physical body, and soul is then identified either with this more spiritual body, or in the Aristotelian manner, with its activities.

This seems like a good place to turn to consider Rüdiger's philosophy in general, as the book here will be his last seen in this blog. Of all the philosophers considered thus far, I think I have done least justice to Rüdiger. Partially this has been caused by difficulties in tracking down his works, but most of the blame must be put on my original inability to recognize his independence of the more pietist side of Thomasian legacy, embodied in Lange.

Sure, Rüdiger does have his antiscientist streak, evident best in his vitalistic physics, which cannot but feel quaint nowadays – just look at his theory of soul. Then again, even here Rüdiger is just part of general progression, following Paracelcian influences inherent in German thought and anticipating ideas of Schellingian philosophy of nature. Furthermore, Rüdiger is not speaking from the standpoint of a mystic, but of a practicing doctor, with considerable empirical information.

Still, the most lasting legacy of Rüdiger lies in his methodological considerations on the differences of mathematical and philosophical thinking and on his criticism of Wolffian notion of ground. Both topics were later on picked up by Kant, and the connection is probably not just accidental. Kant has in both cases been influenced by Crucius who had been taught by a person called Hoffman, who was a follower of Rüdiger. I shall see in a couple of years whether Hoffman considered these topics, but for now, I shall leave this school of philosophy and start to consider eloquence.

Andreas Rüdiger: True and false sense - Sensational mathematics

I have often wondered where Kant got the idea of dividing judgments into analytic and synthetic, analytic referring to judgments where the content of the predicate was included in the content of the subject and synthetic referring then obviously to judgements where this inclusion did not hold. It's not any difficulty in the definitions I am speaking of, but of the nomenclature that would have in Kant's days reminded the reader of two different methods of reasoning, analysis and synthesis.

Originally analysis and synthesis were used by Greek geometers as referring to processes that mirrored one another. In analysis, one assumed that the required conclusion – proposition to be proved or a figure to be constructed – was already known or in existence. One then had to go through the conditions of this conclusion in order to find self-evident principles on which the conclusion could be based.

If analysis moved from conclusions to premisses, the synthesis moved the other way. One began from some principles already assumed or demonstrated to be true and from methods that one already knew how to use, and from these principles and methods set out to prove some new theorem or to draw a new sort of figure.

A certain step in the evolution of the mathematical methods into Kantian judgement types is symbolised by Rüdiger's notion of analysis and synthesis. Just like in the tradition, Rüdiger uses analysis for a method moving from consequences to principles behind them. Yet, he also calls such method judicial and separates it from synthetic method, which he describes as invention. That is, analysis does not produce any new information, just like in Kant's analytic judgement predicate does not reveal anything that wouldn't already be in the subject. Instead, analysis merely determines whether a given proposition is clearly true or at least probable.

Rüdiger's account of synthesis or invention of new and informative truths includes even more aberrations from the traditional account. For Rüdiger, synthesis might involve also mere probable conclusions that are based on the correspondence of various sensations – for instance, by seeing that a certain effect follows always from certain conditions, we may conclude that a new occurence of similar conditions would probably lead to similar effects. Here we see Rüdiger's empiricist leanings, but he does not restrict synthesis to mere empirical generalisations – in addition he also accepts necessary demonstrations.

Rüdiger divides demonstrations into three classes, according to three components required for thinking. One type is based on the verbal form of thinking and grammar: for instance, we deduce from the statement that Jane hit Mary the related statement that Mary was hit by Jane. The second type contains various forms of reasoning, such as traditional syllogisms, but the common element Rüdiger suggests is that all of them are based on the relations of ideas – we might name these forms logical.

By far the most interesting is the third type of reasoning, the mathematical. Leibniz and Wolff had thought that mathematics was based on inevitable axioms and even empiricists like Hume grouped mathematics with logical reasoning. Rüdiger, on the other hand, clearly separates logic and mathematics. Logical reasoning is based on the relations of ideas, while mathematics is based on the sensuous element of thinking.

Rüdiger's position shares some interesting similarities with Kant's ideas on mathematics. Both Kant and Rüdiger are convinced that mathematics are not mere logic, but synthetic or inventive. True, Kant speaks of mathematics as based on intuitions, while Rüdiger speaks of sensations, but this might not be as great a difference as it first seems. Rüdigerian concept of sensation is clearly more extensive than Kant's and would probably include also what Kant called pure intuitions. Indeed, Rüdiger also separates mathematical reasoning from mere empirical generalisations – mathematical truths are not mere probabilities.

The reason behind Rüdiger's desire to separate mathematics from logic is also of interest. Once again Spinoza is the devil that one wants to excommunicate. Spinoza's Ethics is supposedly philosophy in a mathematical form, but Rüdiger notes that this is intrinsically impossible. Mathematics can rely on certain sensations, when it constructs its definitions and divisions – it can tell that triangle is a meaningful concept, because it can draw triangles. Philosophy, on other hand, does not have a similar possibility for infallibly finding sensations for its concepts – a very Kantian thought.

So much for Rüdiger this time. Next time we are back with Wolffian philosophy.

Andreas Rüdiger: True and false sense (1722)

Books on methodology appear to have been a popular choice for philosophers wanting to make their fortune. We have already seen Wolff's Leibnizian take on the topic and also Lange's more Cartesian version. My previous encounter with Andreas Rüdiger and his rather outdated book on physics, with a quaint notion of air, aether and spirit as the fundamental elements, didn't make me expect much. I was pleasantly surprised to find that Rudiger had some intruiging novelties in store with his approach to methodology.

Although Rüdiger's two books have markedly different topics, they both share common enemies. Rudiger's philosophy is clearly anti-Aristotelian, which wasn't strange at the beginning of 18^th century. What is more, it is also anti-Cartesian. The best indication of this in methodology is Rüdiger's denial of any inherent or inborn ideas. Rüdiger is clearly inspired by Lockean criticism in this respect – different cultures have different ideas, and thus we can expect none of those ideas to be inborn. Hence, all ideas – and ultimately, all forms of cognition – should be such that they can be reduced to sensations: they should be combinations of sensory ideas, abstractions from them etc.

Rüdiger's Lockean leanings form an interesting contrast with the work of Lange, the other thus far met Thomasian. As we have seen, Lange attempted to base a pietist philosophy on the Cartesian fundament of a clear cogito. Rüdiger shies away from all things Cartesian, because Descartes' mechanistic tendencies point almost inevitably towards Spinozan pantheism and perhaps also because it is hard to reconcile Cartesian scientism with a devout religious outlook. English empiricists, on the other hand, were not so clearly scientists, and like Hume would do later for Jacobi, Locke offered Rüdiger a good basis for religious statements.

Rüdiger's Christian tendencies modify Lockean philosophy in an interesting manner. On basis of his physical writings Rüdiger notes that animals in general appear to have inborn ideas – at least they manage to do things instinctually or without any training. Rüdiger concludes then that humans should also by nature have inborn ideas, although experience tells us that they do not. This discrepancy is conveniently explained by the biblical tale of fall: humans were supposed to have inborn ideas, but due to their corrupted state, their connection with these ideas has been sundered.

Another modification of empiricism concerns the clarity of ideas, which in general should on Rüdiger's opinion be based on the connection of the ideas with sensations – the more sensuous content we can give to an idea, the clearer it will be. Such empiricist criterion of clearness is obviously meant to weed out confusing philosophical ideas – if it is not clear, discard it. The only exception is provided by Christian mysteries, such as trinity, because they apparently point out the inevitable finity and imperfection of human cognition – they show boundaries humans at least in the present life cannot break.

The idea of boundaries of human cognition shares some affinities with later Kantian philosophy, and even more similarities with Kant we can see in Rüdiger's ideas on mathematics, which I shall investigate next time.

Andreas Rüdiger: Divine physics, the correct road between superstition and atheism, which guides towards the natural and moral well-being of humans (1716)

Some readers might remember that I was rather charmed by Lange's habit of beginning the philosophy of history from biblical times. Well, the same trick does not work as well the second time, hence, I was somewhat dissapointed by the author's insistence that true physics could be found in Genesis and that the further development of philosophy mostly ruined this fabulous start.

The similarity is not accidental, because the obscure author of Physica divina, Andreas Rüdiger, belonged to the same loose circle of philosophers as Lange. Both Rüdiger and Lange were Thomasians, named by their affiliation to Christian Thomasius, first-ever philosopher to write in German. And like Lange, Rüdiger also spent a great deal of his time for criticising Wolff's philosophy, as we shall see in the future.

As the title indicates so well, Rüdiger's book is aimed against both superstition and atheism: superstition divinises the natural world and atheism gets rid of the divine altogether, and the task is to stick with God, but not confuse him with the natural world. True, the book also contains nowadays rather quaint sounding physical theories, which concern all the questions of contemporary natural science – the nature of space, time and motion, movements of planets and stars, basic elements and their combinations, meteorological phenomena, magnetism, plants and animals. But Rüdiger is not satisfied with expounding his own theories, but he also criticises theories of earlier philosophers and shows how his own ideas can help to refute both two extremes.

Most of Rüdiger's enemies are easy to guess: Aristotle and atomists. But the inclusion of Descartes as one of the enemies is somewhat surprising, considering Lange's appreciation of the French philosopher. Yet, Rüdiger's view on Descartes reveals that he understood the implications of Cartesian and generally the modern natural science. In a Cartesian world view, the material things move each other mechanically, through push and pull. The nearest explanation of an event involving material things is another event with other material things. No God is therefore needed, because the eternal movement of matter is enough for explaining the continuance of the movement of matter, and Cartesian physics opens in this way a door to atheism.

Rüdiger's views on Descartes bear a striking resemblance to Jacobi's idea of all modern, mechanistic philosophy leading to atheism, but even more interesting is Rüdiger's idea why Descartes had to fail. The main mistake Descartes made, Rüdiger suggests, is the overt mathematization of physics. Mathematics is a science of possibilities, Rüdiger states. This might be a quip against Wolff, who had stated that philosophy is the science of possibilities. For Rüdiger philosophy is instead the science of what there actually is.

Whereas possibilities meant for Wolff mainly the actual capacities for generating things – real definitions – the possibilities of Rüdiger refer mainly to mere nominal definitions, that is, to mere words which might have no actual reference. In mathematics we can just put together descriptions without any consideration as to whether they describe anything that could be actual. Indeed, mathematics, says Rüdiger, is at least partially false: nowadays we might say that mathematics idealises and hence abstracts from certain characteristics of the actual world. Just because mathematics is an idealised picture of the world, it cannot grasp the true physics.

Rüdiger's idea that mathematics and philosophy are two completely separate disciplines is something that the later German philosophers agreed with: for instance, Hegel made fun of philosophers who tried to use mathematical method, although it was completely unsuitable for philosophical purposes. Interestingly, Kant admits the difference of the two disciplines, but for almost completely opposite reasons than Rüdiger. For Kant, philosophy is the discipline that can only analyse the meanings of concepts, but it cannot construct them – that is, philosophy does not have the means to actualise its concepts, while mathematician can draw his figures at least in pure intuition.

Rüdiger also argues that mathematization of philosophy eventually makes Cartesian proofs for the existence of God futile: Descartes starts by assuming the nominal definition of God, which is completely ineffective in stating anything about what there actually is. Rüdiger's criticism is reminiscent of Kant's later comment that concept of God as such does not involve existence, although ontological proof attempts to deduce one from the other. Rüdiger's further comments that Cartesian mistake is repeated by Spinoza who just assumes the definition of substance as something completely independent of anything else – without noting that such definition might not make sense, because we cannot generate anything corresponding to it: a similar criticism against Spinozan definitions is later voiced by Hegel.

I think that this will suffice for Rüdiger's Physica. Even if I found it philosophically valuable to investigate his theories of air and aether as the basic elements, I would still be in a hurry to move beyond mere physics. That's right, next time I shall begin to do some serious philosophy and tackle the first ever German book on metaphysics.