Right at the end of The Dialogue of the Two Chief World Systems, Galileo makes a distinction between the ‘sensible world’ and ‘a world on paper’(Galilei & Finocchiaro 2008, p.201). He is arguing that the true authority for our scientific theories is not what is written in books but what we can observe with our senses. I already implied at the end of the lecture on Galileo that we should treat this opposition with a little bit of suspicion since he might be guilty of rhetorical exaggeration. First of all, it is clearly not the case that Aristotle, or those who followed him did not use their senses, but equally, Copernicus’s idea hypothesis of heliocentrism was precisely that, and not something that one would come to simply by using one’s senses. Indeed, Descartes is being more honest than Galileo in this regard. He freely admits that the theory of nature, which is at the heart of the new science, that nature is uniform, homogenous, material quantity that is calculable mathematically, and what we see is a secondary phenomenon, cannot be proved by our senses. The opposite is the case. The basic principles of science are what we approach nature with rather than derived from experience. For Descartes, theories do not follow facts, rather facts follow theories.
For Descartes ultimately, science, or the ideas of science, find their culmination in the existence of God. Without the absolute power of God nothing would exist, but equally the beneficence of God guarantees that the most coherent conception of nature (which for Descartes are precisely the laws of the new science and the concept of nature as an homogenous material quantity) must be true of nature itself, despite the fact that I can never experience this ultimate reality.
What happens, however, once we give up this divine assurance? Heidegger’s answer is that Descartes, and Galileo’s, theory of nature is in fact a projection upon nature. We like to think that science describes nature as it appears, but in fact it already pictures nature in a certain way so that it can become an object for science. In other words, there is a determinate way that nature is experience in science, which would be different from how nature appears in art, for example, or when I go for a walk in the wood. Why do we take the scientific model of nature to be the only true account of nature? Perhaps because we are unaware of the historical basis of science or take it to be the natural or common sense way of viewing the world, though if we investigate it in any detail would we see that it is anything but natural in this sense.
What the idea of God hides, then, is that science is the mathematical projection of nature. Galileo conceals this by saying that what science describes is ordinary sensible nature. Descartes knows this is not true, since modern science explains nature through unobservable phenomena, but he conceals the mathematical projection of nature in a different way, by claiming, through the idea of God, that this is what nature is really, even though we cannot experience it.
The key difference between modern and ancient science is not that one is based on experience and experiment and the other is not (as Galileo polemically presents it), but that modern science is mathematical. Numbers are not found in things, nor are things numbers. What is mathematical has to be brought to nature, but for nature to be brought under mathematics it already has to be understood in a certain way. Mathematics provides the certainty (what Descartes thinks of as self-evident truths), but we must already think of nature as something that one could be certain about in the first place.
To think of nature as something certain is to think of it as homogenous. It is because Descartes already conceives of nature as extension (the corpuscular theory of matter) that it is mathematical. It is not because it is mathematical that he thinks of it as extension. Descartes claims that this idea has its validity in the idea of God. Heidegger would argue that this theory of nature is a projection, however useful it might be, of the scientist himself. This does not mean that what science describes is not real, as though its objects were ghosts, but that science never relates to nature empty handed. It only encounters reality within certain limitations. As we shall see when we look at the Question Concerning Technology later on, science sets up the object in advance.
This is why Heidegger will claim that the experiment is crucial to understanding modern science. Again this does not mean that there were no experiments before modern science, but that experiment was not crucial. What is important about the experiment is that it always sets nature up in a limited way. It constrains nature within the limits of the hypothesis that the experiment is meant to test. This is why it cannot be true, even when Galileo said it, that modern science is based simply on observation and experience, for the experiment precisely bypasses our ordinary perception of the world. It is clear, therefore, that the story of Galileo and the tower could only have been a myth. For in terms of the real world, which is not limited by the abstraction of the experiment, observing two balls hitting the ground at the same time is nearly impossible. What Galileo in fact did was, to demonstrate that a heavier object would not fall faster than a lighter one, was to release different balls from a ramp.
To say that the experiment sets up nature in a determinate manner, does not mean that the phenomena observed (the balls accelerating down the ramp) are false, or the theory of free fall is a fiction, but that nature here is experienced in a limited manner. The mistake is to think that the scientific explanation is a description of nature as it is. Heidegger would argue that this is not a scientific explanation but a metaphysical one, and this is why Descartes has to justify it with the existence of God. Once we give up such an idea, then we can see what science must be, which is a projection.
There is then no such as disinterested observation. This is not a criticism of science as being unscientific. Science is scientific because it is already an interested observation. It observes nature through a hypothesis which it then tests through an experiment. This relation between interested observation and experiment, however, is dependent on viewing nature as a whole as something calculable. This is what is common between Galileo, Newton, and Einstein, even though they have very different theories of nature. Science already projects nature as quantifiable and for this reason it measures it. Experiments are only possible as tests of hypothesis because we already assume that nature is something that is measurable. The scientist shrinks the world so that it fits the experiment. But the world already is before we understand it as something measurable. The colour of the leaf already is before it is a wave of light that can be quantified. This does not mean that the quantity is not real for Heidegger, but he will ask us to consider whether the being of the leaf is reducible only to this quantification.
What science cannot do is get behind its own projection. If it were to do so, then it would cease being scientific. A scientist does not ask about the reality of the objects that it considers unless the science itself comes into crisis. I must accept the theoretical reality of the objects I study in order to test the hypothesis. If I were to do so, then I would never begin. Descartes, therefore, has take it for granted that the nature really is nothing but matter in motion, even though no such thing can be observed. What is interesting, historically speaking, is that unlike Galileo, perhaps because he is more philosophical, the projective nature of this theory is more visible to us because of the obvious artifice of the existence of God. However, generally speaking, all science is projection, and more so, when it claims just to be describing things as they really are. Just as much as Descartes metaphysical assumptions predetermine what nature is for him, then so too does the most extreme empiricist.
Although Heidegger is not criticising science as such, since modern science can only function as the limitation of nature by the experiment, what does worry him is the view that science is the only true explanation of anything that we experience and that our world is the very same as the representation of nature in science. Today, like the ancients would have looked for answers philosophy, or the medieval in religion, we now think that all answers are to be found in science. Science is now the ‘theory of everything’, and this everything also includes us.
Why does Heidegger think that such a conception of science, which has the same status as a religion, has hidden dangers? This is because concomitant with the view that nature is only something that is calculable or measurable is the conviction that it is something to be used up by us. Science, then, is not free of political and ethical interests in the broadest sense. This is what Heidegger means when he says that modern science and the essence of technology are inseparable.
The essence of technology and technological things are not the same, just as the tree and the essence of the tree are not the same, otherwise every tree would be identical to a particular tree. What we want to capture is the generality of the tree (Heidegger 1977). When we ask about the essence of something, then we are asking what it means to be that thing that it is. What then is general to technology. Heidegger says that we can think of technology in two ways: as a means to an end and as a human activity. Thus I use a mobile phone to text someone, and texting is something that human beings do. This Heidegger says is an instrumental way of thinking about technology and he does not disagree with this definition. He does not think, however, that it goes far enough. We use something to bring something else about. So we use a kettle to boil water and so on. At heart of instrumentality, therefore, is causality.
What has the history of philosophy to tell us about causality? The ancient, and the medieval, thought of causality in terms of 4 kinds of causality: material, formal, end, and, efficiency. The material cause of something is the matter from which it made, the formal cause of something is its design or plan, the end or telos, is the purpose or function of something, and finally the efficient cause is what brings it about. To explain the cause of something is to explain why something exists. Heidegger uses the example of the silver chalice. The material cause would be the silver it is made from, the formal cause would be the design the craftsman or woman works with, the end or telos, would be its function in some kind of ritual, and the efficient cause would be the work of the person themselves who hammers the metal and heats the fire. But even here, Heidegger suggests, we haven’t got to the deepest level, because why is their causality at all and why only four causes? The ancients and the medieval did not think of causality in the way we did as simply bringing something about, as the match brings about the fire, but being responsible for something. In each case the silver chalice is indebted to the causes. Without these 4 causes the silver chalice would not exist at all.
What is meant by responsibility here, Heidegger says, should not be thought of in the modern way, in terms of morality or ethics, as when we say someone is guilty of crime. The four causes are responsible because they make the silver chalice present. Without them it would not lie there before us, and we would not be able to hold it in our hands. Another way that Heidegger describes this is as ‘occasioning’. The four cause are the occasion of the chalice to be at all.
The way in which ancient philosophy through of this making present was through poiesis (where the English poetry comes from). It is not just poetry or handicraft that brings things into existence, but nature itself. Nature is the occasioning of things, as the apple tree is the occasion of the apple blossom. The craftswoman or man brings forth the silver chalice by making it present, as the apple tree brings forth the blossom by making it present. Something is made present that did not exist before. This making present Heidegger calls revelation or unconcealment, and is how the ancients experience truth.
The essence of technology is also a form of revealing or unconcealment, but it reveals nature in a very different way than poiesis. What Heidegger is emphasising is before technology is instrumental it revelatory. It reveals nature in a certain and determinate way. Rather than poiesis it is the ‘challenging forth of nature’ in which nature is something we use up as a store of energy. Such a way of revealing nature, Heidegger argues, is already hidden in the projection of modern science, which also only views nature as energy. When nature is viewed in this way it becomes a ‘standing reserve’. The river is no longer a course that flows through a valley, but a energy reserve to be used by hydroelectricity. The wood is only experience as a resource to produce cellulose or other industrial products. In the same way, human beings themselves are only seen as ‘standing reserves’ to be used up, such that nowadays it is quite common to hear people talking about human resources, as though there were nothing extraordinary about this.
The particular way in which nature reveals itself to us as something that we determine as standing reserve, Heidegger calls ‘enframing’ (Gestell). He is using this word in an original way. Normally, this word just means a ‘frame’, like in a picture frame. It sounds strange to use an ordinary word in this way, but no stranger than when Plato first used the word ‘idea’, which now sounds completely normal to us. What he means by ‘enframing’ is that nature as a totality must already be experienced by us in a certain way such that we experience both what we encounter in the world, and ourselves, as nothing but standing reserves. In the enframing, nature is reduced to calculation and manipulability. We can see therefore that modern science is at the heart of this process, and why we necessarily think, just as the medieval thought that everything was to be found in God, that science can answer every question. This does not mean that science creates the world around us. It means that since we only experience nature as calculable and manipulable, that science becomes the dominate world picture. This is not because a committee of scientists have decided that we should think like this, but this is generally how we experience nature as such, just as the medieval experienced everything through God, and no more decided this, than we decided our epoch.
Does not mean that Heidegger is anti-science? I think this would be a complete misunderstanding of his argument. Heidegger does not think that one can replace science by philosophy or another way of thinking (religion or spirituality or whatever way you might want to characterise it). On the contrary science only works because it limits nature to a sharply defined model that can be tested by an experiment. Heidegger’s worry is when we confuse this necessary limitation with the totality of nature and even more so when we think of ourselves in this way. But what is true of science is also true of religion in the medieval age or philosophy in the ancient one. What such an inflation of science conceals (that science describes nature as it is), is the political and ethical dimension of scientific and technological world view, where nature becomes only something that is to be consumed and used up. In the age of climate change and ecological catastrophes we might wonder whether such a relation hides a danger we have failed to foresee.
Galilei, G. & Finocchiaro, M.A., 2008. The essential Galileo, Indianapolis, Ind.: Hackett Pub. Co.
Heidegger, M., 1977. The question concerning technology, and other essays, New York: Harper & Row.
 This is the great difference between Heidegger and Kuhn. Even though like Kuhn, Heidegger will also differentiate Aristotelian and Newtonian conceptions of reality (he does not think quantum physics is a decisive difference), nonetheless between these different epochs is the same principle of the intelligibility and calculability of nature.