a few words about what we study last time， when we came to this remarkable text which played an important role in the history of philosophy in the seventeenth century , last time if you remember i explained how is the scientific reading of fictions as superstitions ，a reading elaborated in astronomy and then applied to mechanics ，this reading influences philosophy in general, guess who knew you remember this， it is true for the very gesture of entering into philosophy according to the descartes.
remember about adopt what descartes answered to Gath Sandy, that is to say it is true for adopt inherent in its radical version , that hobbs as we show is also a public opening up his first philosophy, through effective supposition , which aims to be very similar to rules of the astronomers, and it was important to notice that this example hobbs these examples consumes the link between the use of fictions and the study of phenomena.
this is something very important, but there was something else we came to this point during the last part of my previous lecture, when this method i mean failed the method of so the experience or fails to positions , when this method is mobilized in philosophy, fictions do not only work as abstract hypothesis, not only as abstract hypothesis , the crucial example of the cartesian meditations , a road us to discover , what converts a face superstition into our simple field experiment ,what converts eat into a true fiction, a true fiction or as descartes name it a fable, and this is it resides in its narrative dimension .
that was very important okay, so when thought experiments are used in western modern philosophy , they are more complex than abstract hypothesis, okay that possess these narrative dimension, it does not take us out of the rational uh use of fictions , we are still concerned by the rational use of fictions,i finally dealt with the fable of the descartes which is a reduction list , and the mechanist explanation of the visible world, and this was the last point and the reason i wanted you to read this text last time, in this case ,so when fiction comes to its narrative dimension in this case .
philosophy certainly characterized by rational demands, of course , but it must also develop a story the tale the story that stones in phones of the story of revelation , and this was the most important opposition we had we have to remember ,not only between reason and religion , but between two stories .
the first one is given by the revelation, and the second one elaborated by descartes, is uh exploded in the cosmogony , okay so we can we came to the point , but i have to tell you more about this uh cosmogony, cartesian cosmogony, i have to tell you a few words about especially , about these seeds from which stars the earth and indeed everything we observe in this visible world , they most probably could have grown, what are these seeds .
so uh i i want to come to this point , of course i told you that cartesian fable is very long , but and and therefore it is not possible to render in all detail of the hypothesis which according to the couch , only to explain not only the formation of the visible world , but also in all what we can see on earth, that is what physics has to explain, all what we can see on earth.
so i cannot render it in detail , however it's important to describe in a few words , the global structure of these world the global structure of this world produce , remember through the application of the laws of nature , of the mechanical laws of nature to a number of fulls matter .
okay perhaps you know that before descartes, and in fact most recent startled, but at least before descartes, the western tradition uh was differentiating at least four elements , before descartes, at least four elements , the earth , the water the air and the fire , descartes considers that the only distribution of movement into matter according to the laws of nature, of course, the distribution of movement into matter won't separate three elements.
and only three descartes is considering, only three elements from the fluid to the solid dust , that's that is the criteria , we go from the fluid as to the solidus element , most important differences between bodies , according to the descartes rules ones, and each of them is joining in order to concentrate three big three vest regions in the world , three vast regions regions unified invest uh vortex systems , i ah may show you uh an illustration of this book , it looks like this so progressively because of the distribution of of movement into it matter constitutes several vortex in which the three elements join together in vast regions .
so these regions are first the luminous bodies , the luminous bodies which produce lights , okay the luminous bodies formed by the smallest and fastest parts of matter , so what is the fluid as is also the fastest part of matter , okay the transparent bodies transparent bodies consisting in some kind of subtle matter , descartes called it a subtle matter not as you read , these are as fast as the first element , so the shuttle matter , and at least the opaque bodies , the opaque bodies which of course are made of the biggest and slowest parts of matter and gradually to sign the sky , and the planets would separate rules .
they will separate those and this process would will cure for each planetary system, okay and this process these would real cure for each planetary system , certain sky and the plants , so this gives you an id of the main dimensions of the cartesian cosmogony, i would like to emphasize a remarkable point, a very remarkable point, if you think about it , if you think about it , you'll see that the visible world is not only what needs to be explained, the visible world is not only what needs to be explained , in fact the light, the light itself is the very structure of the cartesian world , light is the structure of the cartesian world.
because if you pay attention to it, you will see that the cosmogony cartesian cosmetic woman customer journey， goes fROM a shapeless matter , okay a shapeless matter to an order an distinguishing between bodies, that are producing light , bodies that are producing light , most of these are made of the first element, that is that are blowing delight to pass through them , the sky and more precisely disguise and bodies, that are reflecting the light , okay so you better understand the reason why there is only there are only three elements in the cartesian world .
okay and i think this is remarkable, this physics is not only about the visible world, the light and in fact the conditions of vision give us the structure of the world according to the descartes , so you have more precise ids now about as a cartesian , and cosmology i won't go in more detail this is not useful for us , i especially i won't explain you gravity , according to descartes, uh this is a very complex problem , because of course he does not admit any attracting force , so he has to elaborate and make an equal hypothesis in order to explain rabbit , but and that is the reason why philosophers during the eighteenth century rejected cartesian principles wednesday, came to learn about newton .
okay but this is not the most important at least for us , so i told you it's about the objection between to narratives cosmogony and regulations , descartes however does not settle for this justification, he's adding something very important , these enriching these the statement of his hypothesis, with the postulate a very pay attention to it , please a very important postulates which in fact the first rate , which in fact significantly complicates a postulate , which significantly complicates the question of the model status of these hypothesis.
so what is it about, whsy does it complicate the problem?
because of course everything is given as a pure fiction or to use the terms of his first book, as a fable, told you many times before, but within it within this fatal there is still a necessary principal at work , and that is something important , there is we within this fictions is fable , there is a necessary principal at work , a principle which is always designated as the exhaustion of forms, it's very easy it means that all the possible forms , all the possible forms in matter we look you everything what is possible in matter will cure during this customer journey.
so i repeat this is what we call the exhaustion or false , you have no id of the importance of this postulate during the seventeenth and eighteenth century in europe , it will be discussed by almost all important philosophers, so this is the world uh this is the postulate cartesian postulate , please remember this , matter must succeed lee assume all the forms of which it is capital , all the forms which it is capable of, so please remember this postulate which is at work in the cartesian cosmogony , so own section fiction or fable of a genetically constituted order has been established.
