Martin Knutzen: System of efficient causes, or a philosophical commentary on explaining the interaction of mind and body by physical influx (1745)

If there was one mainstay in pre-Kantian German philosophy, it was the question of the interaction between soul or mind and body. Thus, it is no wonder that we find Martin Knutzen, best known as the teacher of Kant, also tackling the question in his Systema causarum efficientium seu commentatio philosophica de commercio mentis et corporis per influxum physicum explicando.

The setting of the question is clear. We find that certain states of our mind correspond to certain states of our body. This is evident in case of sensations, when e.g. a visual experience corresponds to our eyes receiving light rays. Similar correspondence happens in some cases with emotions, for instance, when a feeling of rage is connected to rapid movement of heart. Finally, often our volitions (like me wanting something to eat) correspond to bodily movements (me moving toward the kitchen). Such correspondence asks for an explanation, Knutzen says, and it is the duty of philosophers to come up with such explanations.

As is familiar, three possible explanations were provided for the correspondence: firstly, the theory of physical influx, according to which mind and body really act upon each other, occasionalism, according to which God in each individual case arranges mind and body to change their state accordingly, and pre-established harmony, according to which mind changes its state according to its own laws and body according to its own laws, but God has ordered these changes to harmonise, when designing the world.

Knutzen does not add any further type of explanation, but suggests that these three explanations were the only ones possible. Explanation, he suggests, requires finding the cause for the correspondence. Such a cause can be either intrinsic to a human being as a combination of mind and body or extrinsic to it. If it is extrinsic, then we are suggesting, in the vain of occasionalism, that some entity outside the human being makes e.g. an arm move, whenever a certain type of volition occurs in the human mind. If the cause is intrinsic to a human being, Knutzen continues, then either one part of the human being (mind or body) affects the other part – this is obviously what the theory of physical influx says – or mind and body form closed causal chains, states of mind affecting further states of mind and states of body affecting only further states of body. In the latter case, the correspondence or harmony of mind and body is just a brute fact, which must then be further explained, as in the theory of pre-established harmony, by God fixing the causal chains of mind and body to harmonise with one another.

How then to decide between the three systems? Knutzen notes that the question cannot be decided by experience, since we cannot literally perceive mind and body acting on one another or God intervening in the causal chains, not to mention God making before the creation of mind and body a decision to harmonise them. What we are then left with is to find some reasons why we should prefer one system over the others.

Knutzen’s strategy is to ground his reasoning in the philosophical paradigm in Germany of his time, that is, Wolffian philosophy, by making references to Wolff’s works, whenever possible. Thus, Knutzen begins by pointing out that mind or soul is a simple substance, which has both intellect and free will and particularly has representations of its own body. As a simple substance, he continues, the mind is immaterial, while the body is a composite of many parts. Then again, even bodies must ultimately be composed of simple substances or elements, since otherwise a body would have an infinite amount of parts, which Knutzen thinks an absurd idea.

Knutzen goes on by defining what an action means: a thing acts, when it has in itself a reason why something else exists or changes. The reason in question is called a force, which is thus a tendency to act or generate and change things. Furthermore, Knutzen adds, force is always a sufficient reason for acting, that is, if no obstacle prevents, force generates an action, no matter what.

Following Leibniz’s relational definition, Knutzen takes space to be an order of coexisting things. A place of a thing is then just a definite mode of being in that order or of relating to other things. Thus, at least finite substances cannot exist in the same place at the same time. Motion, furthermore, is a change of place: thing changes its relation to other things. Because this change affects only the relations of a thing, it does not intrinsically affect the moving thing. The motion is still based on something more substantial, Knutzen says, namely, the motive force making a thing move.

All existing things must be determined in every manner, Knutzen says. Particularly, their relations to other coexisting things must also be determined, in other words, they must exist in some definite place. This truth, Knutzen continues, holds also of simple substances, such as the elements of the bodies. Furthermore, since bodies move, elements must also move. Then again, they do not fill a space or have an extension, since they have no parts, of which they would consist.

Two things cannot occupy the same place at the same time, which means, Knutzen suggests, that a thing resists the other taking its place. When a thing moves, it takes the place of another thing, in other words, it must overcome this resistance through some force. Particularly, Knutzen concludes, the elements of the body must use force to overcome this resistance of other elements and push them away, thus, the elements truly affect one another. Since a cause can be known from its effect (an accepted truth in Wolff’s ontology), we could even say that through changes caused by other elements an element represents or perceives other elements.

If elements act upon another, we can thus say that some simple and perceiving things interact with each other. This raises the probability of the mind also interacting with its body, Knutzen suggests, since the mind would interact with the body by interacting with the elements, of which the bodies consist. Of course, there is still a possibility that a mind would be different from elements on this point: perhaps interaction with elements of matter is somehow an imperfection that would not befit the status of a mind. Yet, Knutzen points out, God is thought to act on elements, and as God is absolutely perfect, the interaction with elements cannot be an imperfection.

In addition to showing the probability of the system of physical influx or real interaction of the mind and the body, Knutzen adds some further points to convince the reader the choose this system over the others: occasionalism is based on God doing constant miracles, while the system of pre-established harmony cannot explain why the bodies should be created in the first place. Furthermore, Knutzen also tries to directly prove the truth of the interaction. Just like other simple substances, a human mind must exist in some place, and indeed, it exists in a place where it is constantly together with its body. Thus, the mind must move with its body. Either it is passively moved by the body – and the interaction is real – or mind moves itself – and then it must be able to push other simple things around it, in other words, to interact with them.

Opponents of the physical influx had often stated that such an influx is just an empty word that has no meaning. Knutzen thinks this is a false accusation, since we have a perfectly good explanation of what physical influence means: real interaction of a mind and its body. Then again, he admits we cannot completely comprehend what the physical influx is like, since an interaction of simple things is something we cannot fully understand: we humans require distinctions in our cognition, but such an interaction can only happen instantaneously and no distinctions can be made in instantaneous changes. This is still no detriment to the truth of physical influx, since there are many things, Knutzen says, we can know to be true, although we cannot intuitively grasp them.

A further common objection to the system of physical influx was that it breaks the law of nature which states that the quantity of the motion in the universe cannot be changed: when I will my hand to move, I create new motion. Knutzen’s answer is that this supposed law is based only on observations of material objects and their interactions and that we need not suppose that it is correct for the interaction of the mind and the body.

Knutzen also considers the objection that we really cannot derive a force for moving material objects from a force of representing things, which should be the essence of a human mind. Knutzen thinks such a derivation is fairly simple. A force of representation, he explains, does not mean just a passive capacity to represent things, but active striving to try to represent things. Since representations of the mind correspond to the states of the body, the force of representation must also involve a force to change the body and its place in the universe.

Finally, Knutzen answers some objections that suggest physical influx would degrade the worth of a human mind. Firstly, he says, physical influx does not make the mind completely passive and dependent on the body, since the mind can also affect the body and does also have activities beyond interaction with the body.

Furthermore, Meier continues, physical influx does not contradict the immortality of the mind. Such a denial of immortality was based on the supposition that since the theory assumes sensations to be caused by the body, the destruction of the body would lead to a life with no sensations and thus without any consciousness. Knutzen notes that there is no reason why we shouldn’t get new bodies after our death. In addition, even if we did not get a new body, we might have sensations of other kinds, such as direct experience of other minds. Finally, Knutzen concludes, even if we wouldn’t have any sensations, our mind could still do a lot of things, such a abstract reasoning, which would entail consciousness.

Martin Knutzen: Reasoned thoughts on comets, in which their nature and properties, together with the type and causes of their movement are studied and presented, including a short description of a remarkable comet in the present year (1744)

If there’s one thing Martin Knuzen was famous for, then it was introducing Immanuel Kant to Newtonian physics. Yet, Knutzen’s own understanding of Newton’s ideas was at least in some regards rather shallow, especially when it came to the mathematical machinery behind Newton’s physics. For instance, Knutzen predicted that a comet would appear during 1744, because the same comet appeared regularly every few years. A comet did appear then, but as more capable astronomes noted, it wasn’t the comet Knutzen identified it with.

Knutzen himself was apparently rather unconcerned about such criticism. Even his book on the topic, Vernünftige Gedanken von den Cometen, darinnen deren Natur und Beschaffenheit nebst der Art und Ursachen ihrer Bewegung untersuchet und vorgestellet, auch zugleich eine kurze Beschreibung von dem merkwürdigen Cometen deß jetztlauffenden Jahres mitgetheilet wird, has no indication of Knutzen even considering such a possibility. Knutzen’s motivation for his book, beyond introducing the comet of 1744 to a wider audience, is to criticise superstitious ideas where comets are regarded as harbingers of doom.

This motive lies even behind Knutzen’s more questionable thoughts, like the false identification of the 1744 comet. Knutzen emphasises the regularity of the comet’s movement, as a guarantee that they are natural phenomena. He uses a simple induction to justify the assertion that comets continue to move with the same regularity as they have appeared to do - it is equally justifiable, Knutzen says, as when Adam noted after a few days that the sun will always rise in the morning. Such regularity statements seem the more justified, the shorter the time between two appearances. Thus, Knutzen is very eager to show that 1744 comet was the same as had been seen a couple of years ago. This leads him to insist more generally that there are less comets in our solar system than other astronomers and even Newton had assumed - seemingly different comets have often been just appearances of one comet, seen in different parts of the sky due to slight changes in the comet’s orbit, crossing Earth’s ecliptic at different points at different times.

Knutzen’s main point against taking comets as omens is based on showing a failure of another inductive move. Knutzen notes that if comets were such omens or signs of bad events, they would either be causally connected to such events or then the connection would have to be an effect of God’s arbitrary choice, similar to when he in the Bible sets up rainbow as a sign of his promise to not flood the world again. Knutzen then points out that neither possibility really works. If God had set comets as an arbitrary sign, he would have had to teach this sign to us, either through revelation or through experience. There’s no mention of such a sign in the Bible - in fact, the book even speaks against looking at such astrological signs. Even experience speaks against this - if God had meant comets as arbitrary signs of bad things, then he surely would have meant them especially as a sign for astronomers, who are most certain to see these omens, but astronomers who have found most comets have not been particularly unlucky.

Similarly, Knutzen shows that there seems to be no natural connection between comets and bad events. Undoubtedly sometimes comets have appeared during a time when a war has been going on or some king has died or some other calamity has fallen upon some country. Indeed, since Earth is big, it is almost inevitable that some type of disaster is almost always going on at some point of the globe. If a comet would have some noticeable effect on the earthly goings-on, it would have to be a global effect, but there’s no correlation between global crises and appearance of comets. In fact, Knutzen continues, there’s no clear causal mechanism by which a comet could influence such events. For instance, suppose someone would say that comets could cause wars by having a force to aggravate people. Problem is, such a force would not just cause wars, but Hobbesian chaos, where everyone attacked everyone else. If comets would cause only wars, then such a force would have to affect only royalty, but it is unclear how and why such a lifeless and unconscious object as comet could pick out kings and queens as its target.

In his wish to show that comets have not harmed Earth in any manner, Knutzen goes a bit too far and insists that comets could never have an adverse effect on Earth, discounting even the notion that a comet could hit the Earth or at least fly so close that its gravity might cause some disturbances. Thus, Knutzen discounts the worries of his contemporary, William Whiston, who had suggested that such catastrophic meetings had indeed occurred before - Jewish tradition told that Noah had seen a comet before the flood, which Whiston saw as a sign of the mythical flood being an effect of a watery comet hitting Earth. Knutzen was convinced that this tale was just yet another coincidence, and since comets had never hit Earth, they would not hit it in the future. Then again, he suggested that the Jewish tradition might explain historically why comets were universally feared: Noah associated for the rest of his life comets with disasters and taught his descendants to also do so.

Although Knutzen did not then believe in comets as divine signs, he did speculate on their having some purpose in the divine plans. Comets, Knutzen deduced, are just like planets in being mostly solid objects, surrounded by an atmosphere formed from gases and dust. The main difference with the regular planets is that the orbit of comets is very oblong and so a comet is sometimes very close to the Sun, sometimes very far away from it. When the comet approaches the Sun, the increasing gravity and the heat make the comet’s atmosphere appear as a tail. When the comet again changes its course to the outer reaches of the Solar System, it still retains some of its heat - and perhaps, Knutzen suggests, the whole purpose of a comet doing such a trip is to transfer some of this heat to where it wouldn’t otherwise get.

Next time, we shall once again return to Wolff's account of natural law.

Martin Knutzen: Philosophical study of immaterial nature of soul (1744)

While most of the philosophers of the Wolffian school were busy writing grandiose compendiums of philosophical disciplines, Knutzen, the teacher of Immanuel Kant, was satisfied with more succinct treatment of individual problems. For instance, Philosophische Abhandlung von der immateriellen Natur der Seele (a translation from Knutzen’s Latin original) treats the nature of human soul. In fact, it is a defense of the immateriality of latter, against materialists, who would state that soul is nothing else but a material thing.

Knutzen’s work divides into two parts, first of which positively argues that soul is immaterial, while the second criticises the materialistic arguments against the immateriality of the soul. While the first part of the treatise is not that original, it is at least a good summary of the usual Wolffian argument for the immateriality of the soul.

The starting point of Knutzen’s argument is the simple experience that we are conscious or aware of things. This what is conscious of things is then called soul, without first any indication whether soul is material or immaterial. Now, one thing soul can be conscious of is the soul itself. An important condition for this self-consciousness is the ability to distinguish oneself from other things - this ability is something we’ll see even Fichte emphasising as an important part of human self-consciousness.

Next question Knutzen makes concerns the conditions of the capacity to make distinctions. Firstly, he notes that the soul must have representations of several things, secondly, these various representations must belong to the same subject, and finally, the representations must be compared by this same subject. In other words, soul, as the subject of these various acts, must form an absolute unity - a sort of focus, from which all these “rays of action” start. In particular, the soul cannot be a mere unified complex of parts, Knutzen says, which wouldn’t really be an absolute, but only accidental unity.

Knutzen’s proof is then almost complete. What he still requires is to show that matter is no absolute unity. This he can do easily, because matter was defined to be a complex substance consisting of many parts, which were also substances. To make things even clearer, Knutzen asks us to consider, in a Condillacian manner, a statue that would think itself. Part of such a statue might represent one part of the statue and another part would represent another part. Yet, such a combination of representations would be no unified representation of the whole statue. At most, one or more indivisible parts of the statue might think of the whole statue and at the same time of themselves, but such an indivisible part - a monad - would then not be a complex substance nor material.

The second, bit more original part of Knutzen’s book is dedicated to showing faults in arguments purporting to show materiality of soul. Furthermore, Knutzen considers the question why people endorse materialism. He comes up with two answers. Firstly, he suggests that materialists are often unable to understand anything beyond what they sense and thus unable to fathom the existence of something that cannot be sensed, such as an immaterial soul. Secondly, he insinuates that many materialists just wish to discredit the idea of immortality, so they wouldn’t have to worry any retribution of their sins.

Knutzen considers seven different arguments for material nature of soul:

1) A clear reason for a materialist understanding of soul is that body appears to determine soul in many ways: for instance, bodily weaknesses and old age hinder thinking. Knutzen notes that these facts could also be explained by suggesting that soul uses body as an instrument when thinking something - when the instrument is somehow flawed, like when the body ages, thinking becomes difficult for soul. If an old person would suddenly get a new, young body, its ability to think would be increased.

2) Knutzen has rejected the first argument of materialists, because he thinks causal interaction between soul and a body is at least as good an explanation for certain facts that could be explained materialistically. Now, another argument for materialism starts particularly from this supposed interaction between soul and body - all causality requires substances touching each other, which makes sense only when these substances are material. Knutzen is able to quickly deal with this argument, because there is no clear reason why all causality would happen through direct contact, and indeed, Newtonian account of gravity appeared to show that even material substances could affect one another through long distances. In the end, Knutzen notes, there is no need to assume that an instrument would have the same essence as its user, just like a violin is very different from a violin player.

3) Yet another argument for materialism starts from similarities in the behaviour of parents and their children, which could be explained if souls were produced from the souls of their parents. Knutzen notes that just because soul of a particular parent and a particular child are similar, other children in the same family might bear no resemblance to their parents. In any case, the similarities in behaviour might be attributed to the similarities of instruments used by souls, that is, bodies.

4) Another materialistic argument begins from the natural assumption that soul appears to undergo changes - while we are conscious of this now, we will be conscious of another thing later. If we then assume that all changes are based on motion, then soul would have to be a movable thing and therefore material. Like with an earlier argument, Knutzen can simply deny that all changes require motion - indeed, it is quite conceivable that even some material changes, like when colour of an object changes, might not need motions.

5) Locke famously noted that while matter as such appears to have no capacity to think - as shown by material substances that do not think - God with his omnipotence would surely be capable of giving the matter a power to think, which would make the assumption of immaterial soul superfluous. Knutzen’s answer is that the idea of thinking matter is a complete contradiction, thus, even God could not make matter think, no matter how omnipotent he is.

6) It is a pity that most German philosophers of the time considered animals only in brief snippets, leaving their status in the world system quite unclear. Still, many philosophers had noted that animals did have souls, but their souls differed crucially from human souls - while humans could think, animals probably didn’t. Knutzen notes that materialists might insist that animal souls can think and that they are material, which would suggest that same things could be said about human souls. While it would be easy to deny that animals think, Knutzen does not do this, but admits that animals might have this capacity. Yet, he at once points out that animal souls cannot then be material.

7) The last straw of the materialists is to insist they can explain all phenomena of human consciousness materialistically, so that no supposition of immaterial substances is required. Knutzen goes very far in describing the current theories about nerve fluids etc. Yet, he finally notes, there seems to be no clear connection between thinking and movements of nerve fluids.

Martin Knutzen: Philosophical proof of the truth of Christian religion (1740)

Considering that the interpretation and reinterpretation of religions and especially Christianity will be one of the main hobbies of the post-Kantian German philosophy, it is somewhat surprising to see that religion has played so little role in the discussions of the German philosophy in the beginning of 18th century. True, Christianity has been a clear background of all the philosophers we have dealt with and religious topics like God and immortality of the soul have been discussed especially in works concentrating on natural theology. Still, there has been little discussion of religion itself, barring some remarks of religion as a cult in natural theology and of religious communities in natural law.

Martin Knutzen's Philosophischer Beweiß von der Wahrheit der Christlichen Religion feels then quite a fresh work. Knutzen himself is probably best known as a teacher of Kant, and one might hypothesise that Kant might have been inspired by Knutzen's work. Then again, Knutzen's philosophy of religion has a very different basis from later Kantian and post-Kantian philosophies of religion. It could be called broadly Wolffian in the sense that Knutzen follows the formal trappings of the Wolffian school, with its supposedly strict definitions and proofs.

Knutzen's proof has essentially two steps. The latter step, in which Knutzen tries to show the divine origin and reliability of Bible stories and especially of the account of the resurrection of Jesus, is less interesting, as it relies more on historical interpretation and Bible exegesis than any deep philosophical insights. Yet, it is of interest in the sense that Knutzen outlines different criteria for deciding the truth of various matters. While the metaphysical or ”geometric” truth should be based on nothing else but the nature of things and physical truth should be based on the actual natural laws, a third kind of or moral truth is dependent on the moral nature of human beings – in other words, we can be reasonably sure that some event has occurred if its denial would involve people behaving against their character. Thus, Knuzen cites as evidence for the truth of the gospel that the supposed enemies of Christianity have accepted it as a historical account – it would go against human nature that one would outright accept the stories of your rivals, if one wouldn't already accept them as reliable.

The first step in the proof involves more philosophical speculations. Knutzen notes that all humans are obligated to obey God's commandments, which coincide with the natural law – firstly, following the natural law just means following our own nature, and secondly, as a divinely instituted law it has the further obligating element that it is based on the will of a person responsible for creating us. Furthermore, Knutzen notes as an empirical fact that all human beings break the natural law in some manner, how insignificant it may seem. Importantly, he does not suggest that this empirical fact would require some sort of original sin as an explanation – it is just something that happens and definitely not a destiny of fallen human beings.

Still, because of this tendency to break the natural law, human beings are in debt to God, Knutzen continues, and because their whole existence depends on God, this debt is infinitely great. In fact, it is so great that nothing that human beings could by themselves do would ever be enough for cancelling this debt – not even if they would conduct the rest of their lives according to the tenets of natural law. Because God is also just and must require some sort of recompensation for the sins of human beings, an infinite punishment should be in store for all human beings.

Knutzen thinks that this problem of the infinite guilt of human beings should be the basis of all true religion – a religion that would just repeat all that natural law has to say would be completely futile. He is also convinced that in addition to Christianity no other religion in the world tackles this question (admittedly, he has only limited information on these other religions). Since Christianity is the only answer given to the problem of infinite guilt – in effect, the answer is that a) God has many aspects and that b) in one aspect he took the shape of a human being and by his death paid the infinite debt – it must be the true religion, just as long as we know that this dying person was truly divine (this is supposed to be proven by the second step, since resurrection is for Knutzen a clear sign of divine power).

Although Knutzen's proof is clearly full of holes, it does address an important issue – that people do have the feeling that they have something to pay for – and recognises that this feeling is a basis of lot of religious sentiments. Indeed, we might be able to draw a clear line from Knutzen's proof to the romantic idea of an alienation of human beings.