 Hi, I'm Peter Adamson and you're listening to the History of Philosophy podcast, brought to you with the support of the Philosophy department at King's College London and the LMU in Munich. Online at historyoffilosophy.net. Today's episode, Spirits in the Material World. Tilesiu and Campanella on Nature. If Aristotle or any one of the legion of Aristotelian philosophers who worked in the 2000 years after his death were confronted with a textbook on modern physics, they would be stunned by many new and unfamiliar ideas, from gravity to magnetism to the structure of the atom. But they might be even more surprised at what was missing, where they would ask themselves are all the references to the four elements, to the natural places toward which the elements tend, fire and air moving upward, water and earth downward, where above all are the references to forms. For the Aristotelians, understanding nature was in large part about understanding forms, both accidental and substantial. Ultimate matter, in their worldview, was pure potentiality to receive form. So whenever scientific investigation revealed something about determinate properties, causal powers, or the natures of things, this was a matter of understanding the forms that reside in matter. There was no one moment that European philosophy gave up on hylomorphism, that is the theory that all things are constituted from matter and form, in Greek houle and morphe. Science did not move from Aristotelian physics to modern physics in just one step. The change was instead, and as usual in the history of philosophy, incremental. This is nicely illustrated by the profound challenge posed to Aristotelianism in late sixteenth century Italy by several thinkers, above all, Bernardino Telesio and Tommaso Campanella. Their natural philosophy was explicitly presented as a rejection of Aristotle and put forward with appeals to the value of freedom in philosophizing. As Campanella said, such freedom led to the sort of innovations that Europe was seeing at this time, ranging from the telescope to the printing press and gunpowder weaponry. All the new doctrines, he observed, please and render admirable both the state and religion, and they make it so that subjects turn more willingly to their duties. From foreigners, they elicit admiration and obedience. Yet the self-consciously original and innovative new science, put forward by Telesio and eagerly adopted by Campanella, was itself a version of hylomorphism. Telesio made this point himself. In his treatise On the Nature of Things, first published in 1565 and appearing later in revised editions, he argued that if Aristotle had been more consistent in following his own principles, he would have reached very different conclusions. In particular, he reminded readers that in the first book of Aristotle's Physics, we are told that all change requires three factors. Something that undergoes the change, the feature that is acquired or lost as a result of the change, and the absence of that feature. Abstractly speaking, we can say that what undergoes change is matter, the positive feature is form, and the lack of form is privation. Yet Aristotle's own physical theory looks more complicated. Even his basic elements have more than one positive feature, since fire, earth, air, and water each have two primary features. For example, fire is hot and dry, water is cold and wet, and so on. Telesio wanted to keep things simpler. For him, there were only three principles. Matter, heat, which plays the role of form, and the absence of heat, also known as cold. With these three principles, he thought, he could explain the whole universe. Thus, the Telesian universe is Aristotelian in general structure and un-Aristotelian in detail. Neither Telesio nor Campanella after him adopted the new Copernican astronomy, so they still had the earth unmoving at the center of the universe, just as Aristotle had said. But where for Aristotle the celestial realm was constituted from a fifth element that is neither hot nor cold, Telesio said that the luminous heavens are the body that is primarily hot, heat being closely associated with light. The earth by contrast is cold and is thus opposed to the nature of the heavens. These two, earth and the heavens, are the first bodies in our cosmos. Other bodies are formed through their interaction, as the active principles of heat and cold struggle against each other producing ever more complex natures. Most basically, heat causes expansion and cold contraction, which is where moisture and dryness come from. These two properties are derivative from hot and cold, not on a par with them, as Aristotle believed. More complicated phenomena arise thanks to the stars, especially the sun. As they move over the earth, the increased heat in the affected parts of earth causes them to transform into vapors, fluid, metals, and stones. More generally, variation in heat and cold due to heavenly motion can produce the bewildering multiplicity we see around us. According to Telesio, heat and cold are not bodies. Instead, body is that which they act upon, and for him this is matter. What undergoes change, in other words, is not a mere seat of potentiality for the reception of form, as in Aristotelianism, it is a corporeal mass, a stuff, whose total quantity never changes. In a dramatic shift away from the Aristotelian tradition, Telesio recognizes bodily matter, heat and cold, as substances, and thinks that all the more complex natures that arise in matter are accidental to it. Though matter has its own rudimentary nature, insofar as it is corporeal, it is inert and passive, even dead as Telesio puts it, echoing a remark made by Plotinus, who called matter a decorated corpse. Matter and the earth made from it have a tendency to move towards the center of the cosmos, but this is not a natural downward motion like the one Aristotle ascribed to earth and water, rather it is just a matter of falling, since matter has no active power at all. Cold and hot, by contrast, are active principles. Here he has in mind not just the capacity to warm and chill, or as we already saw, to cause expansion and contraction, heat and cold also tend to pursue what is similar to them, as when fire comes together to make ever larger blazes, and to repel what is dissimilar to them, as when water is boiled away by fire. So the two fundamental principles are always working to preserve themselves and destroy what is contrary to them. This is an observation with far reaching implications. It leads Telesio to claim that the two agent natures, heat and cold, must always be capable of sensation. We lazily assume that sensation must involve sense organs, but this is not the case, as such organs are needed only for more sophisticated forms of sensation. The mere fact that cold and heat flee one another shows that they are in a very crude way, able to respond to what is around them, while stones and plants have yet more sophisticated forms of sensation. As Campanella will later explain in his exposition of Telesio's views, sensation is really just the ability to respond to being affected. So we should count warm, fluid air, for instance, as being highly sensitive because it shapes itself so readily around other objects. In general, says Campanella, heat and light are the most sentient things in the world and the entire world senses in greater or lesser degrees. More advanced creatures like animals and humans have a higher form of sensation, but this is still a fundamentally physical phenomenon. In humans, sensation occurs when the warm spirit that flows through the body is affected by things in the person's environment. The spirit Telesio is talking about here is a borrowing from the medical tradition. Galen explained all manner of animal capacities by appealing to pneuma, a subtle warm and airy sort of breath that flows around the body. Yet again, Telesio is putting a traditional idea to untraditional ends. For him, the spirit is not the instrument of the soul, as doctor philosophers like Avicenna and Ficino had taught, the spirit just is the soul, so the composite of spirit and body is the same as the whole animal. Here we can see the extent to which Telesio has indeed departed from hylomorphism, as the Aristotelians understood it. The soul is no longer a substantial form, but warm air or spirit circulating through the body. However, this literally breathtaking materialism comes with a major caveat in the case of humans. Telesio believes that, in addition to the seed-like soul that is spirit, humans alone among animals also have an immaterial divine soul, which is created directly by God. It turns out then that his materialist revision of Aristotle is complemented by a borrowing from Platonism. Yet Telesio's novel philosophical approach shows itself even here. He gives the divine soul little importance when it comes to our knowledge of the natural world because it is dependent on the deliverances of sensation. This in fact is how Telesio begins his treatise On the Nature of Things, by saying that where the ancients used abstract reasoning to do science, he will take recourse only to sensation. The Aristotelians insisted that true knowledge is universal in character and involves grasping the essences of things, but Telesio argues that universal thinking is inferior to sensation. It is really just a vague generalization of what we have experienced. To recall that all the giraffes one has encountered had long necks is wholly derivative of and less informative than the knowledge one has when inspecting a particular giraffe. Campanella gives the example of seeing something approach from a distance, first thinking it is some sort of animal or other, then realizing it is a human, and only then realizing which particular man is coming. This illustrates the fact that grasping a particular true sensation is more informative than thinking abstractly about universal species and genera. Yet it was the latter that the Aristotelians supposed to be the most appropriate for science. Francis Bacon famously called Telesio the first of the moderns, and you can see why. Already in the 1560s he was proposing a new natural philosophy that resonates with those that will emerge in the 17th century. But I want to emphasize again the way that this grew out of a close engagement with Aristotle. Even the appeal to heat and cold as fundamental explanatory principles has some basis in Aristotle's writings, in particular in the meteorology, whose newfound importance during the Renaissance we've had occasion to mention in a previous episode. In fact, even Telesio's irreverence toward the ancients could find support in the ancients themselves. While attacking Aristotle, he quotes Aristotle's own justification for criticizing his teacher, Plato, namely that we must value truth above even our friends. Likewise, Telesio's adherent Antonio Percio, who wrote a treatise on the nature of fire and heat, in defense of this new natural philosophy, said that the ancients valued scientific innovation, so why shouldn't the moderns? One reason that followers like Percio appreciated Telesio was that he offered the chance to provide new answers to old questions. Telesio wrote a treatise on colors, for instance, in which he explained the spectrum between white and black in terms of light giving heat and its absence. In medicine, too, it seemed useful to appeal to heat and the mechanistic processes derived from heat. We saw that already with Cardano, who appreciated Hippocrates' identification of soul with heat. For a concrete application of the idea, we can mention Telesio's theory of the pulse, according to which it is caused by the compression and expansion of spirit in the vessels, which results when the heart dilates and contracts. The phenomenon of sleep was another point in favor of Telesian theory. It is no coincidence that we are warmer when we are awake, engaging in sensation and other activities and cool down when the bodily system shuts down at night. With all due respect to Percio, the most famous thinker to be carried away with enthusiasm for this new theory was Tommaso Campanella. We already met him as author of the famous utopian work City of the Sun, but that is only the most renowned of his many writings. He also composed treatises on politics, theology, the evils of Protestantism, metaphysics, and natural philosophy with the latter part of his output heavily influenced by Telesio. As a young scholar, Campanella even traveled to meet the great man, arriving just too late and getting to see only Telesio's corpse. This being the Renaissance, Campanella dealt with the setback by writing a poem. He had encountered Telesio's ideas during a period of intense study which involved surveying ancient literature and more recent offerings, seeking to compare what he found with the book of nature. This was a favorite metaphor of Campanella's. God has given us two books, the Revelation of the Bible and the world itself. In a typically provocative line, he observed that the universe is the better of the two books for those who know how to read it, since it is inscribed in living letters, not like scripture in dead letters, which are only signs, not things. Campanella shared Telesio's delight in complaining about Aristotle's failures, to read the book of nature correctly. He was thus at pains to distance his fellow Dominican, Thomas Aquinas, from the stain of peripateticism. Surely, Aquinas could have been no follower of Aristotle, he observed, given that he would hardly have defied the condemnations the Parisian authorities aimed at Aristotelian philosophy. If Aquinas nonetheless explored that philosophy, it was only to expose its weaknesses. But Campanella was no more slavishly committed to the Church's teachings than those of Aristotle. He spoke up in defense of Galileo, writing an apology on his behalf in 1616. As he wrote to Galileo, his goal was to show that, This despite the fact that, as I mentioned, Campanella was not himself persuaded by the Copernican astronomy, being expounded by Galileo, he simply bridled the notion that scientific inquiry would be met with suppression and censorship. No doubt he recognized something of himself in Galileo, having seen the works of his hero, Telesio, put on the list of prescribed texts by the Inquisition, and having himself been arrested for heresy. As we saw in the episode on Utopias, Campanella spent 27 years in prison, and wrote many of his works during that time, including the defense of Galileo, making it an even more impressive act of courage. Already before these travails, Campanella must have known he was flirting with danger by embracing Telesian philosophy. When he was still a young prodigy, a cardinal asked to assess him for the Duke of Florence said of him that he was to the ignorant, but that possessed neither substance nor foundation. To promote Telesio's natural philosophy was to court controversy, and in fact Campanella's first work was a rebuttal of a treatise entitled Defense of Aristotle Against Telesio by Giacomo Marta. Not content to argue for the codency of Telesio's conception of nature, Campanella added invective aimed in Aristotle's direction, dismissing him as a non-Christian of poor character. Far more important than Aristotle's personal failings though, were his failings as a philosopher. We should look not to him for truth, but to our own experiences. No less than Telesio, Campanella was devoted to the principle that philosophy should be grounded in sensation. While he allowed that it could be fitting to rely on authority, one should take heed only of predecessors who likewise took their guide from experience. But to these empiricist strictures, he added an emphasis on the primacy and importance of self-knowledge. He contrasted perception of external objects to the constant awareness we have of ourselves, which he called presential knowledge. Here Campanella is finding a bit more for Telesio's so-called divine soul to do, by making intellect or mind a self-directed power. Like Augustine before him and Descartes after him, he thinks that thoroughgoing skepticism can be defeated by appealing to the phenomenon of self-knowledge. Your grasp of yourself is one thing you cannot be wrong about. The mind is also our way of grasping supernatural things, that is, God and the angels, and our possession of it allows us to outlive the death of the body. In the end it will be through the mind that we achieve true happiness by contemplating the divine. As with Telesio, it looks like a healthy measure of Platonism has been mixed into Campanella's antidote to Aristotelianism. That impression is not a misleading one. Another author he admired and cited frequently was Marsilio Ficino. Ficino's revival of Neoplatonism may seem a strange combination with the down-to-earth explanatory accounts offered by Telesio's physics, but Campanella was able to find points of commonality. Notably that the Platonists recognized a world soul that vivifies the entire cosmos. Now this is not exactly what Telesio had wished to say. He held that air and stones are sensitive, not that they are insult. His was a theory of universal perception, not one of universal animation. But Campanella could find comments in Ficino that fit tolerably well with the Telesian culture, as with a passage from Ficino's commentary on Plotinus that spoke of a hot spirit nourishing the world and breathed out by the world soul. He also found common ground with Platonism when it came to the ultimate destiny of humankind. High-flown speculations about an immortal life contemplating divinity sound pretty far removed from a physical theory grounded in empirical observation, but remember that Telesio's active principles, heat and cold, constantly pursue their own preservation. When we look towards immortality, we're just doing the same. I said a few minutes back that the new science adopted by Telesio and Campanella had the virtue of providing new answers to old questions. One of those questions was, how exactly do the heavens influence the world down here where we live? By providing heat which comes through light. Telesio argued that light is not itself hot, but is produced as a kind of byproduct when it is reflected off a surface. There was another question to answer here though, how much did the heavens influence our lower world? Sure, we can see that the moon affects the tides and the sun makes it hot, but can you for instance use observations of the planets to predict the future of a newborn child? To determine the best time to launch a war or embark on a voyage? In short, is it possible to do astrology? This is a topic on which Campanella changed his views. He began as a critic of astrology, but wound up writing a major work on the subject. I won't be going that far, but I do want to devote an episode to the influence of the stars and other so-called occult phenomena like magic. Many of the thinkers we've discussed, from Pico and Ficino to Campanella, had things to say on these topics, which are pretty far from the interests of philosophers nowadays, but were in the Renaissance seen as intimately connected to natural philosophy. So join me as I try to conjure up another 20 minutes or so of podcast magic next time here on The History of Philosophy Without Any Gaps.