Presentation on theme: "The Players in Our Drama 1 2 3 4 5 The Need for Context Modernity first and most generally constitutes itself as a rejection of or battle against the."— Presentation transcript:
The Need for Context Modernity first and most generally constitutes itself as a rejection of or battle against the pre-modern. It largely views itself as “new,” “original,” and “revolutionary.” So one cannot understand the modern without understanding the pre-modern (or the modern view of the pre-modern, even if this is not accurate). So context is necessary. In particular, early modern science in Descartes and Bacon did not begin simply as a rejection of an older, supposedly incorrect, set of views or “facts,” but in a new way of doing science altogether, a new way of deciding what is true and what is false (or so it claims!). For fear of the Catholic Church, Descartes intentionally hid his true intentions in the Discourse and the Meditations. To Mersenne, 1641: “… and I may tell you, between ourselves, that these six Meditations contain all the foundations of my physics. But please do not tell people, for that might make it harder for supporters of Aristotle to approve them. I hope that readers will gradually get used to my principles, and recognize their truth, before they notice that they destroy the principles of Aristotle.” His plan was to show his method is better for religion itself, and oh, by the way, also supports Copernicus and his view of science.
1. Brief Historical Background and Menu Some Dates: (322 BC) Death of Aristotle – (90 - 168 AD) Life of Ptolemy – (1543) Copernicus’ On The Revolutions published – (1596) Descartes Born – (1619) Descartes discovers the universal method of science in a stove heated room – (1632) Publication of Galileo’s Dialogue Concerning the Two Chief World Systems – (1633) Galileo condemned by the Inquisition for heresy and formally denies Copernicanism; Descartes decides not to publish his physics, since it teaches the motion of the Earth – (1637) Descartes publishes the Discourse on the Method, but still suppresses his physics – (1641) Descartes publishes Meditations on First Philosophy [i.e. on metaphysics] – (1644) Descartes publishes Principles of Philosophy, which contains his metaphysics and his physics of the entirety of nature in several volumes – (1650) Descartes dies in Sweden – (1687) Sir Isaac Newton publishes his Principles, which contain his famous three laws of motion and the inverse square law for universal gravitation.
Menu for This Lecture Review Aristotle’s understanding of science (physics or “natural philosophy”), and particular his views on the use of mathematics. Look briefly at Ptolemy’s Aristotelian model of the solar system (at that time viewed as the whole universe). See the view of the relationship between physics and mathematics is present in Ossiander’s Introduction to Copernicus’ On the Revolutions of the Heavenly Spheres. Also that expressed by Pope Urban VIII, who was Pope when Galileo was condemned for Copernicanism in 1633. Review Copernicus’ and Galileo’s actual views on the nature of physics and the role of mathematics in it, and in particular Galileo’s disagreements with the Aristotelians of his day. Introduce Descartes and the Origin of the Discourses in an attempt to justify the Copernicus’/Galileo’s mathematical view of nature. Examine the main parts of Descartes’ strategy for justifying this. Draw some conclusions for science and philosophy.
A. Traditional “Aristotelian” Position Mathematical models are useful hypotheses, i.e. “useful fictions.” Yet no matter how useful or beautiful or simple a model may be, it cannot be true if it conflicts with the results of “natural philosophy”. Since the job of the Astronomer is to invent the most useful hypothesis, they are not concerned with truth at all.
The Aristotelian Order of Science First Philosophy or Metaphysics: The Fundamental Science, which Demonstrates the Principles used in all Other Sciences. Physics or “Natural Philosophy”: Concerns the Motions and Changes of Physical Bodies – Draws its first principles from Metaphysics. Guided by experience (the senses) and metaphysics. (Gives the real reason. Answers the Question: Why?) Astronomy and Mechanics: Concerns Forms Separate from Bodies. Branches of Mathematics Aimed at Calculation and Incapable of Demonstrating Principles of Physics. (Only describes what we see. Not concerned with why. Does not give reasons.)
From Ossiander’s Preface to Copernicus’ On the Revolutions of the Heavenly Spheres (1543) “For it is the job of the astronomer to use painstaking and skilled observation in gathering together the history of the celestial movements, and then – since he cannot by any line of reasoning reach the true causes of these movements – to think up or construct whatever causes or hypotheses he pleases such that, by the assumption of these causes, those same movements can be calculated from the principles of geometry for the past and for the future too.” “For it is sufficiently clear that this art [i.e. astronomy] is absolutely and profoundly ignorant of the causes of the apparent irregular movements. And if it constructs and thinks up causes – and it has certainly thought up a good many – nevertheless it does not think them up in order to persuade anyone of their truth but only in order that they may provide a correct basis for calculation.”
B. Position of Pope Urban VIII (Friend of Galileo, but also Pope when Galileo is condemned.) God is infinite beyond our comprehension in terms of both knowledge and power, thus no supposed explanation we give can be certain in the least. That is, since God is so great, we must admit that he could do anything in any way, and surely in ways that surpass our comprehension. “It would be excessively bold if someone should want to limit and compel divine power and wisdom to a particular fancy of his [i.e., if the physicist should insist that he/she can demonstrate anything true of nature]” (Galileo, Dialogue Concerning the Two Chief World Systems, 270).
C. Copernicus, Galileo, Descartes, et al. Despite Ossiander’s Preface, Copernicus did intend to demonstrate the true nature physical motions of the planets. But he did not have any solid empirical evidence. Rather, he believed his system to be true, because he thought it the most systematic and beautiful, and thus most fitting to be a work of God. Since this system was mathematical, however, he asserted that one can see this truth only with “the vision of the mathematician.” While we cannot know all things, as God does, we can know individual things with as much certainty as God. These are the things we conceive and prove using mathematical arguments. This is possible because God created the world in accordance with mathematics. Galileo: “[Natural] Philosophy is written in this all-encompassing book that is constantly open before our eyes, that is the universe; but it cannot be understood unless one first learns to understand the language and knows the characters in which it is written. It is written in mathematical language, and its characters are triangles, circles and other geometrical figures; without these it is humanly impossible to understand a word of it, and one wanders around pointlessly in a dark labyrinth” (The Assayer, 1623).
Summary of Galileo’s Position Against the Aristotelians 1. The Aristotelians rely too much on AUTHORITY, TRADITION and BOOKS instead of THEIR OWN JUDGMENT. 2. The Aristotelians are too “EMPIRICAL,” i.e. they rely too much on the bare evidence of the senses (e.g., the Earth does not move, bodies naturally slow down, etc.) 3. The Aristotelians do not employ MATHEMATICAL DEMONSTRATIONS, and indeed falsely believe that mathematical truths are not EXACTLY true in the physical world (e.g. they believe no argument using perfect spheres or perfectly smooth surfaces has any validity in the physical world where there are no perfectly smooth spheres)
What must be done to prove Galileo right? Prove, somehow, that mathematics is the key to the method of they physical sciences. How? Answer: Find a new metaphysics that replaces the Aristotelian Metaphysics and shows that physical reality is ESSENTIALLLY MATHEMATICAL. (Descartes: Prove God exists and created the world using mathematics! But how??) Prove that one can only reach the truth by trusting one’s own judgment (quiets the Aristotelians once and for all). Prove that the human mind is capable of absolute certainty, i.e. God-like Knowledge, in those instances where it 1) relies on its own judgment fully and 2) employs mathematics properly. (Partial Answer to Pope Urban VIII) Show that this metaphysics agrees better with the Christian Religion than does Aristotle’s (Full answer To Urban VIII) – That is, show the same metaphysics that supports a mechanical view of the universe also proves God’s existence, immortality of the soul, etc. Crazy!?
2. Descartes and the Origins of the Discourse on the Method (published anonymously, 1637) 0) Descartes Life in Brief: Birth (1596) – Schooling – Research, Travels: Beeckman and the Corpuscular Philosophy – Stove heated Room: Universal Method of Science – Suppression of his Physics – Publication of the Discourse – Meditations on First Philosophy – Principles of Philosophy - Death 1) He first discovered no certainty in knowledge gained from books, custom or even his own experience, and thus resolved to accept nothing as truth that was not certainly true. “Thus I gradually freed myself from many errors which may obscure our natural light and make us less capable of heeding reason.” (10) “But regarding the opinions to which I had hitherto given credence, I thought that I could not do better than undertake to get rid of them, all at one go, in order to replace them afterwards with better ones, or with the same ones once I had squared them with the standards of reason.” (14-15) 2) He then reflected on how science could best be constructed, and found common knowledge to be defective mainly in its lack of a single secure method. It was an accumulation of materials from different sources, when it should be one well-structured whole.
3) He looked to logic and mathematics for help in discovering a universal method, because they were most reliable, but found even these too defective. 4) Finally he resolved on four rules: i) Accept nothing that is not certain, ii) break all problems down into their simple parts, iii) understand all complex matters on the basis of their parts, and iv) practice running through his reasoning several times so he could see all the parts of his argument combined into a whole. 5) Finally, at the end of the Part Two, Descartes reveals that this method requires a new foundation, and so an investigation into Metaphysics or First Philosophy: “But observing that the principles of these sciences must all be derived from philosophy, in which I had not yet discovered any certain ones, I thought that first of all I had to try to establish some certain principles in philosophy. And since this is the most important task of all, and the one in which precipitate conclusions and preconceptions are most to be feared, I thought that I ought not to try accomplish it until I had reached a more mature age than twenty-three…” (21-22)
3. Descartes’ Metaphysical Strategy for Founding Modern Science (Discourse, Part Four – Meditations) Step 1. Deny every supposed truth that can be doubted at all. (Methodological Doubt): Result – Customs or traditions, books (Aristotle) and the senses (experience!) are not sources of certain truth. retreat into the mind or soul, which alone I know immediately Step 2. Discovery of the fundamental truth, “I think, therefore I exist” [Aside: Discovery at the same time of the true nature or essence of the self: thinking.] Step 3. Examine this fundamental undeniable truth to discover what makes it impossible to deny. This is found in its being absolutely “clear and distinct.” Adopt these as the Ultimate Criteria of Truth. If the idea can be made clear and distinct in my mind, accept it as certain; if not, reject it as false. Step 4. Prove from within my own mind (thinking self) that God exists. Proof One: I am aware of myself as imperfect or as limited. But to think myself as limited, I must have the idea of something unlimited. I cannot be the source of this idea, and indeed no being less than God could be the source of it. Therefore, God exists. Proof Two: The idea of God is the idea of a being with all perfections. Existence is a perfection. Therefore, God exists.
Step 5. Prove God is not a deceiver. Proof: Deception is only suitable to a being with limited power. God is of unlimited power. Thus God cannot deceive. God is therefore truthful. Step 6. If God is truthful, then since he is the creator of my being, everything that I clearly and distinctly represent to my mind will necessarily be true. Put differently: If God is good and truthful, then he certainly will not make it that I am deceived when I use the best and indeed the only guide to truth that I find within myself. 4-5-6: “However much the best minds study this question, I do not believe they will be able to give any reason sufficient to remove this doubt unless they presuppose the existence of God. For in the first place, what I took now as a rule, namely that everything we conceive clearly and distinctly is true, is assured only for the reasons that God is or exists, that he is a perfect being, and that everything in us comes from him. It follows that our ideas or notions, being real things coming from God, cannot be anything but true, in every respect in which they are clear and distinct.” (38) Step 7. The Clincher for Mathematical Physics: The most clear and distinct representations, and indeed the only clear and distinct representations, that I have of external physical things, are those treated in geometry. Therefore, external physical things in reality have nothing other than geometrical characteristics: “The essence of bodies is extension.” Thus colors, heat, cohesion and even weight, must be reducible to geometrical properties. (e.g., heat is only motion of small bodies)
Descartes’ Strategy I think, so I am God: creator of me and the world, most perfect, so also all powerful, all knowing, all good, so all truthful and not a deceiver. The World as it Really is Prove God Exists Creates World Clearly and Distinctly in My Mind Because of God
Major Conclusions for Science: 1)Genuine knowledge is only possible through mathematics, and indeed, through the construction of mathematical models, the entire truth of the physical world can be known. 2)The Aristotelian natural philosophy, which does not employ a mathematical method, is necessarily false. 3)Every physical body, including therefore also the human body, is entirely nothing but a machine, i.e. the operations of the whole depend upon and are a necessary consequence of the character of the parts from which it is constructed in exactly the same way as a geometrical description of a body is composed of the geometrical descriptions of the parts.
General Major Conclusions for Philosophy 1)To the extent that the body is determined by its mechanism, it acts independently of the soul. 2)Since clarity and distinctness can only be “seen” in one’s own mind, the only path to truth is by reliance on one’s own judgment. No need to listen to the Aristotelians or give Authority to Aristotle! 3)Since we know and can prove using clear and distinct ideas (mathematics!) that things can happen in no other way than this, Pope Urban VIII is wrong. We can demonstrate natural truths with certainty. To Mersenne, 1640: “I would think I knew nothing in physics if I could say only how things could be, without demonstrating that they could not be otherwise. This is perfectly possible once one has reduced physics to the laws of mathematics.”