the game René Descartes, the name has echoed in the halls of philosophy for more than 300 years.People have always enshrined him as the ancestor of modern European philosophy and the pioneer of rationalism.His philosophy not only presents a new point of view and conclusion, but also brings about a new era. "Cartesian philosophy has an extraordinary complexity, so rich that one can find in it the source of all modern philosophy. The great masters of seventeenth-century metaphysics (Malebranche, Spinoza, Le Bunitz) built their system by reflecting on the philosophy of Cartesian. ... The philosophical analysis of Locke, Berkeley, Hume, etc. has its Cartesian source. Kant's famous 'Copernican revolution' , in a sense, is only a resurrection of the supremacy of the subject that is thinking about all things thought that Descartes gave. Hegel regarded Descartes as a hero. And the more recent Husserl , titled one of his works Descartes' Meditations."

Cartesian philosophy is a unity of many spirits. As a methodological Cartesianism, it emphasizes that the only thing we can rely on is the proof of reason; as a scientific Cartesianism, it regards the existence of our thoughts as the most important thing. Definitely something.Descartes' achievements in philosophy alone are enough to shock the world, but his research field is far beyond the scope of philosophy.He founded analytic geometry, "reflection and reflection arc theory", discovered the law of refraction of light, and expressed brilliant ideas such as the indestructibility of matter, the conservation of motion, and the evolution of nebulae in the universe.Any one of these achievements could make him a giant in the history books.

As the initiator of modern European rationalism, Descartes ushered in a new era of philosophy, and the ax he used to "open the sky" was his brand-new scientific methodology and the concept of "cogito".Philosophy must start from "I think", that is, from "self-awareness", so it advocates "rationality" rather than authority.Kant's "Copernican revolution" is just a more mature reproduction of Descartes' "Cogito" supremacy.Cartesian philosophy is both familiar and strange to us.We often talk about Cartesian philosophy, but rarely can explain Cartesian philosophy clearly.What exactly is Descartes' new methodology? "I think, therefore I am" is well-known in the philosophical circles, but what is its real meaning? What role does it play in modern European philosophy? People say what they say, but how many layers does it include? Is Descartes’ proof of the existence of God a simple repetition of Anselm’s ontological proof? The problem of the relationship between mind and body (or soul and body) is the central problem of Descartes’ philosophy, but this What is the epistemological significance of this mind-body distinction? How did Descartes separate them and how did he unify them? At present, the discussion of this work in our country's philosophical circles is still relatively weak.Therefore, in the preface of this book, we intend to make a more detailed and comprehensive introduction to Descartes' philosophy system, methodology and his main arguments, so that people can have a complete outline of Descartes' philosophy as a whole.This will be very meaningful for understanding the content of Descartes' thesis and grasping its ideas and essence. 1. The ideological source and background of Descartes' philosophy The era of Descartes was the era of rapid advancement of European and American science.About 50 years before Descartes was born, Copernicus published the six-volume "On the Revolutions of the Celestial Spheres" in 1543, which comprehensively expounded his heliocentric theory, pointing out that the earth rotates once a day and revolves around the sun once a year.This theory destroyed Aristotle-Ptolemy's theory of the center of the earth, which had been ruled for more than 1,000 years and was regarded as the "scientific basis" by scholasticism.Also in 1543, Vesalius published the book "The Structure of the Human Body". He summed up a large amount of information he personally observed on human anatomy, systematically described the structure of the human body, and denied that the Christian God used the ribs on a man to create a human body. Nonsense about women, Jesus raising the dead through resurrection bones.In terms of astronomy, Galileo discovered the transformation of Venus with a telescope. He also discovered the law of inertia, the law of free fall, the law of throwing objects, the law of pendulum isochronism and many natural laws, and applied these laws expressed through mathematics to the natural world. , Outlined a mechanical world blueprint.The great progress of natural science broke the natural view of feudal science and had a great impact on the formation of Cartesian world view living in this era.

However, in Descartes' time, scholasticism and theology prevailed in Europe.This school of thought was originally derived from Aristotle, and became the mainstream of European philosophy after collation by St. Thomas and supplementation and interpretation by other scholars.Since this school combines the wisdom of Aristotle, St. Thomas, and many other scholars, it is naturally of high value, or contains a lot of truth.However, by the seventeenth century, scholasticism seemed to be degenerating.The main issues become dead dogma, no progress is made, and the minute details are debated endlessly.The example that people use to satirize this school is, "How many angels can stand on the tip of a pin?" They use the three-stage form to train the skill of debating.For example, the person who made the claim first proposed a three-paragraph to prove his claim.The other party proposed a three-paragraph rebuttal.The defender counters the opponent's argument by means of a distinction, and the opponent then offers a three-paragraph refutation.They continued to debate in accordance with this fixed form.Such a form of debate is a trick of playing with logic and does not do much to increase knowledge.At the same time, this unchanging form will inevitably become tiresome after a long time.Facing such a traditional philosophy and traditional method, Descartes acquired a concept that he wanted to establish a new method and a new set of philosophy: he planned a philosophical revolution.

No philosophy can get rid of its cultural tradition, just like plants cannot leave the soil, they are more or less a secretion and accumulation of traditional culture, so we can see the continuity of human thinking process.However, the appearance of any new philosophy is a kind of negation and a revolution of traditional culture.They are a kind of mutation and development in the "heredity of the species", which in turn allows us to see the discontinuity and leap of the human thought process.Descartes is the pioneer of modern philosophy, but the content of his philosophy still allows us to clearly see that it has Greek origins and medieval heritage; it was developed under the influence of modern science and civilization in this special area of ​​France The son of the age rising on the land; the accumulation of history and the creation of reality weave into a web of human cognition and development, and Cartesian philosophy is just a knot in this web.Descartes' thought has been inspired by the sages in many ways.

Plato's philosophy had a profound influence on Descartes.Descartes saw that the creative genius of the pre-Socratic Greeks had invented the sciences of geometry and arithmetic, the sciences of attaining undoubted knowledge, the conditions for the formation of Plato's philosophy.And Plato himself once believed that only by firmly grasping the knowledge of geometry can it be possible to acquire knowledge in higher fields.It can be said that mastering geometry is the basis of studying philosophy.If the inscription at the entrance of Plato's Academy reads: "Students who do not understand geometry must enter", then Descartes' philosophy originated here.Descartes took geometry as the basis and model for philosophical research, and made philosophy achieve the certainty that geometry can achieve.In addition, there is an inevitable connection between Plato's "reminiscence theory" and Descartes' "innate idea theory".Plato doubled the world, thinking that besides the real phenomenal world, there is also a world of ideas, the world of ideas is the prototype, and the real world is the copy of the world of ideas.People's understanding of things is not a reflection of the real world, but a memory of ideas.Plato believed that the soul lived in the world of ideas before reincarnation, and it had a direct understanding of the world of ideas.But when it is born behind the human body, it forgets its original understanding of the truth due to the hindrance of the body, and only under the stimulation of sensory experience can people recall these forgotten truths again.True knowledge, therefore, of the nature of things, is nothing but the recollection of ideas.Learning is to reawaken the soul sleeping in the body. The immortality of the soul and the reincarnation of the soul have become the basis of Plato's "reminiscence theory".

Descartes transformed Plato's recollection into "the theory of innate ideas", arguing that people have innate innate ideas, which are eternal truths endowed by God.He regards the "axioms" of geometry and the "law of identity", "law of contradiction", "law of excluded middle" and "God" in logic as innate, inherent in people's hearts. When the soul and body are separated, they can be discovered. The theme of "Meditations on First Philosophy" is to demonstrate the existence of God and the immortality of the soul.From this, we can see the similarities between the two of them.  If it is said that Cartesian philosophy is still closely related to the thoughts of sages, then the closest one belongs to Augustine's philosophy.

He believes that true philosophy is the love of God, true philosophy can only be combined with true religion, and true philosophy can only be found with true religion.The two themes he established for philosophy are "soul" and "God", and the task of philosophy is to know self and God.Like Augustine, Descartes regarded "soul" and "God" as the two central concepts of his philosophy, and established the central task of his philosophy to prove the existence of God and the difference between soul and body. Augustine gained knowledge about God through Plato's ideas, and regarded God as the eternal existence of the most true, the best, and the most beautiful.We can only experience the existence of God through the heart by entering into the mind, self-thinking, and self-reflection; proving the existence of God depends on a mysterious intuition, and God is just a transcendental concept.Descartes combined Augustine's spiritual intuition, Plato's idea and Anselm's ontological proof to prove that God himself exists.Regarding the existence of human beings, Augustine believed that my existence is proved by my thinking, the certainty of my thinking proves the certainty of my own existence, and my thinking is absolutely true.At the same time, I will make mistakes, which is a problem with my thinking. From my mistakes, I can prove that I exist; if I do not exist, I will never make any mistakes.Hence the conclusion, "if I make mistakes, therefore I exist".Descartes absorbed Augustine's proof method, and also proved the existence of me from the existence of thinking, and put forward the proposition "I think, therefore I am".I am a thinking thing.A thinking thing is a thing that doubts, understands, affirms, denies, wills, refuses, imagines and feels.I doubt everything, but the existence of this self who is doubting everything cannot be doubted.Therefore, I am doubting, and therefore I exist.This can be said to be the ideological origin of Descartes' "I think, therefore I am" proposition.

Although Descartes' own life criterion is: "Only seek to overcome oneself, not to overcome fate; only to change one's own desires, not to change the order of the world." But when Descartes was just born, the civil war (1562-1562) 1598) is not over yet.The war was a desperate struggle between religious factions, and the result of the struggle was that Henry IV succeeded to the throne.The rule of Henry IV brought prosperity and peace to France, and enabled capitalism to develop rapidly in a period.Although the power of the bourgeoisie at that time was still weak and not enough to overthrow the feudal system, "at that time, the old feudal hierarchy tended to decline, and the medieval civil hierarchy was forming the modern bourgeoisie. Neither side of the struggle had yet overwhelmed the other." Descartes' dualism philosophy It is a reflection of this social situation.Looking at the development of Cartesian philosophy in the context of the times, Cartesian philosophy comes from two aspects: vertical and horizontal.From a vertical perspective, it is from Plato, Augustine to Descartes; from a horizontal perspective, humanism, Protestantism, scientific materialism, and the religious, economic and political struggles in France at that time directly influenced Descartes.The two dimensions of vertical and horizontal constitute a "Cartesian coordinate", which marks the growth point of Cartesian philosophy.

2. Descartes' philosophical system and its formation process Descartes wanted to build a huge philosophical system, which is the tree of human knowledge he described. "The first part of philosophy is metaphysics, which consists of the principles of knowledge in which the principal attributes of God, the immateriality of the soul, and all clear and simple ideas in us are explained. The second part is the physical Science, in which, after we have discovered the true principles of material things, we proceed to examine how the whole universe is composed in general, and then in particular to examine the nature of the earth and all the bodies most commonly regarded as being connected with it, Natures like air, water and fire, magnets and other minerals.

Therefore, it is necessary to study the nature of planets, animals, and especially human beings separately, so that we can discover other sciences that are useful to human beings in the future.So philosophy as a whole is like a tree, its root is metaphysics, its trunk is physics, and its branches developed from this trunk are all other sciences.They are in turn reduced to three principal sciences, namely, Medicine, Mechanics, and Ethics—I mean the highest and most perfect moral science, which presupposes the whole knowledge of the other sciences, and is the highest order of wisdom. "Descartes' tree of human knowledge is composed of metaphysics, physics and other sciences that are beneficial to life. Descartes believes that the fruit is not in the trunk, but in its branches, and the function of philosophy is reflected in various specific sciences. In The branches of medicine, mechanics and ethics are the fruit of human happiness: medicine is directly aimed at restoring and protecting human body and health, mechanics is to relieve and liberate human physical strength, and ethics is to make human Peace of mind and happiness. All learning is for man, directly or indirectly. The purpose of philosophy is man, his happiness.Descartes was unswervingly determined and full of confidence in completing his great cause, and determined that as long as he was alive, he would spare no effort to leave a complete set of philosophy to the world.Descartes' philosophy is compatible with all human knowledge.It includes not only metaphysics (that is, what we call philosophy), but also physics (that is, philosophy of science), and experimental sciences, such as: astronomy, geography, physics, chemistry, biology, physiology, psychology, etc.Taking metaphysics as the root and physics as the stem, three branches emerge from this stem, namely medicine, mechanics, and ethics.He believes that philosophers should not care about the study of metaphysics or physics, but should focus more on medicine, mechanics and ethics.Therefore, if a philosopher has made achievements in medicine, mechanics, and ethics, he is not in vain as a philosopher.Descartes firmly believed that people could break through the constraints of nature by virtue of philosophy, prolong their lifespan and reach the state of happiness.Even so, the root is very important and fundamental, it is the root of the tree's existence.Without roots, neither the trunk nor the fruit can survive.This is the relation of metaphysics to philosophy.Therefore, an unquestionable metaphysical principle must first be found before there can be physics, and then medicine, mechanics, and ethics.According to Descartes, no philosopher in history has known to do so.Although there are many talented people among them, if it is not because of haste, they make rash judgments, or they are self-sufficient and stubborn, and the result is always nothing.Some regard prejudice as the standard; some follow the crowd, without fixed opinions, it seems that only the number of people in favor is required, regardless of whether the people who agree are laymen, the opinions of the public are enough to become the condition of truth; some superstitious authority, based on what someone said It is regarded as the golden rule and cannot be doubted.So the current task is to quickly establish a sound, new philosophical foundation.This enviable science is to eliminate the indeterminate science of the Middle Ages, and to make science as certain as mathematics.Descartes wants to extend the certainty of mathematics to all sciences, so that not only geometry and algebra can be unified, but all sciences can be unified.This is to devise a method of unifying the sciences, and to find a sure foundation for the whole system of philosophy. From November 1619, Descartes used mathematics as a reference to design his methodological rules, and used these rules to study various scientific issues.He said: "I also continued to practice the method I had planned, because besides carefully guiding all my thoughts generally according to these rules, I still left a little time from time to time, especially for solving mathematical problems. Some difficult problems are sometimes used to solve some other scientific problems, and I can make the problems almost exactly the same as the mathematical problems, so that they are separated from all the principles in other sciences that I find not solid enough." After 9 years of experiments and conclusions , Descartes wrote the book "Rules to Guide the Mind", which basically embodies Descartes' methodological thought. The content of this book and the later work "Introduction to Method" are basically the same.His method enables one "to acquire some knowledge that can be very useful in life, to find a practical philosophy in place of the speculative philosophy taught in schools, by which we can understand fire, water, air, stars, sky and The power and function of all the objects around us are as clear as we know how many trades our craftsmen have, so we can use them accurately in various applications, and thus become the masters and possessors of nature.Therefore, Descartes' method can become a beacon to guide the progress of science. In November 1928, a meeting was held at the residence of the Pope's special envoy in Paris. Celebrities from all walks of life attended the meeting. Descartes was also invited to attend the meeting and delivered a speech.He refuted the view that science can be based on probability with rigorous arguments, pointing out that science can only be based on certainty.He believed that, according to the principles of his method, any truth could be clearly demonstrated.His method enables one to see whether the stated proposition is probable or not, because in this way one obtains the same knowledge and certainty that the rules of algebra provide.Descartes' thought was approved and supported by most people, especially Beryl, the cardinal, who was more interested in it, and urged Descartes to engage in this great work - to develop his philosophical system. Establishing a philosophical system has been Descartes' wish for many years, and Beryl's support and urging strengthened Descartes' determination to realize this wish.Descartes recalled: "It was 8 years ago (that is, 1628) that this desire made me decide to leave all places where I might have acquaintances, and live in seclusion in a country like this", which is the Netherlands.For more than 20 years since the end of 1628, Descartes has been engaged in his philosophical production. 3. Descartes’ methodological system On the day when Shilin philosophy declined and modern scientism rose, scholars generally lost confidence in the system of medieval philosophy, and many people even wondered whether philosophy could be established and whether absolute truth existed Cast a skeptical look.However, Descartes was not like this. He always admired the value of philosophy. He said: "The word philosophy means the study of wisdom. What we mean is not only the wisdom of dealing with people, but also the completeness of things that people can know." Knowledge is useful for directing life, maintaining health, and inventing technology." He also believed that the existence of philosophy is an obvious fact.This can be seen from his works, especially the methodology.Descartes did not think that all previous philosophies were false, he just wanted to find a stable and accurate method to grasp the truth.He is not inventing truth, but ordering it into a visibly solid system.For this reason, he created a set of rationalist methods, formed a relatively complete scientific methodology, and used this set of methods to establish his own philosophical system. (1) The starting point of methodology The widely doubted method is the starting point of Cartesian methodology.Because Descartes felt that he had accepted a lot of wrong opinions as true from an early age, and this knowledge and some opinions formed based on it were unreliable and very suspicious.School education can only aggravate his boredom, and there is no other progress in studying except that he feels more and more ignorant.Descartes believes that we should "seriously and freely carry out a general liquidation of all my old opinions". "If I want to establish something solid and enduring in science, I must spend my lifetime expunging everything I've ever believed to be true, and starting anew fundamentally. No." Descartes' general doubt is a methodological doubt, which is different from the nihilism of skeptics who seek to discover the truth and obtain certain knowledge.Because in all the knowledge we have received, some are true and some are false; some are more certain and some are less certain.And they are so closely intertwined that we form a lot of prejudices in our minds, believing these things to be true, and blocking our knowledge of the truth.Anyone who wants to discover the truth must engage in general doubt at least once in his life.For this general doubt, Descartes made two vivid metaphors: one is to compare it to building a building, in order to find a solid foundation, first remove "floating soil and sand, so as to find rock or clay".The second is to compare this doubt to picking rotten apples. If a person has a basket of apples, "he is afraid that some of them are stale and wants to take them out so as not to spoil the rest. How can he proceed? Does he Will first empty the basket, then go over the apples one by one, pick up the ones he sees to be good, put them back in the basket, and throw the rest away? Just the same, these people have not studied philosophy well before, and they keep in their minds various opinions which they have begun to accumulate before. When they are quite reasonably convinced that most of these opinions do not correspond to the truth. , they try to distinguish some opinions from others, because they are afraid of confusing the two kinds of opinions and making the whole opinion unreliable. In order not to make mistakes, it is better to throw them all at once. Which of them are true and which are false, and then study them one by one, retaining only those which are believed to be true and beyond doubt." General doubt is a method of discovering truth. However, Descartes has no doubts about the existence of truth, the question is how to obtain the truth.In this regard, he believes that in addition to abandoning the ills of haste, arbitrariness, and stubbornness, there should be a standard of truth to distinguish true from false.Therefore, Descartes has another belief, that is, the existence of conscience.He held that conscience equals wisdom in practical life, and reason in theoretical life.Everyone has a conscience, and they are basically equal, but why until today, people still cannot use conscience to establish a common metaphysics? According to Descartes, this is not because each other's conscience is different, but because each other is applying conscience The above situation is different, or the method of application is different, or the object of application is different. "All science, taken as a whole, is equal to human intelligence. It is usually single and identical, but if applied to different things, the response will naturally be different. As the sun shines on various objects, We see all kinds of different shades. This belief in intellectual equality becomes the basis of his method."  Descartes is convinced that of all knowledge, mathematics is the most qualified to be called a true science.It has the conditions of true science and the method of reaching truth, so he uses the form of mathematics as the form of all knowledge.At the same time, the mathematical method is also the method of general knowledge, "that long series of coherent reasoning is so simple and easy that geometers are accustomed to apply them to obtain things that are difficult to prove. It is the same situation, as long as you don't take anything that is not true as true, and follow the deductive procedure to push from one fact to another, then there will never be any remote or hidden truth. Therefore, it should be Seek the law of intellectual activity in mathematics. There is only one science, and therefore there is only one method, and the mathematical method is also the method of other sciences. This method is a collection of real and simple rules. Anyone can apply it, and it is very convenient, as long as If you observe it carefully, you will never take the false for the real, and as time goes on, knowledge will gradually increase unexpectedly and reach the highest knowledge that the intellect can know." There are two basic methods used in mathematics: one is intuition; the other is deduction.The process of deducing truth is to reach conclusions from definitions and axioms.Intuition is the simplest basic activity of the intellect, the direct insight of the mind, which can provide us with unshakable absolute truth.For example: the fact that each person has insight into his own existence; the fact that thoughts exist; the fact that a triangle has only three sides and a sphere has only one surface.As soon as we look at these facts with the eye of the mind, the perception is immediately evident, and the mind has distinct ideas of these facts.These ideas are mere ideas.In the course of studying any problem we usually encounter such naive ideas.The solution to all problems must rely on them.Deduction is also an intellectual activity, but unlike intuition, they are not purely intellectual activities. After certain truths (or definitions) must be assumed, some conclusions can be drawn from these definitions.For example: After we know the definition and theorem of a triangle, we can deduce that the sum of the interior angles of a triangle is equal to the sum of two right angles.The function of intuition is therefore to furnish the latest principles of science and philosophy.Deduction, on the other hand, is the application of these principles to establish some theorems and propositions.In other words, intuition is the basic principle of invention, and deduction leads to the most basic conclusion.However, Descartes believed that deduction was flawed, because different conclusions were often deduced from the same principle, so there should be another way to correct it.The remedy for this is experience, the so-called appeal to facts.  (2) The Essence of Method Descartes thought: "Method, I mean sure and simple rules, if one follows them exactly, he will never take the false for the true, never will his spirit Efforts expended aimlessly will always increase his knowledge gradually, and thus gain a true understanding of all that is not beyond his capacity." The reason why we did not get definite knowledge of things in the past is because we There is no method of acquiring this knowledge, or the past method is not appropriate. "However, if our method correctly explains how mental insight should be used so as not to fall into the error of contradiction, and how deduction should be discovered so that we can gain knowledge of all things, I do not see how What is needed to make this method more complete, since I have already said that no science can be obtained except through mental intuition and deduction." That is to say, the content of this method has two aspects, one is to explain correctly how to use intuition, One is to explain correctly how to discover deduction.Intuition and deduction are the essence of this method. The so-called intuition, Descartes believes: "'Intuition', I understand, is not the evidence of the inconsistency of the senses, nor is it a deceitful judgment that originates from the imagination wrongly constructed, but a pure and focused mind. Concepts given to us so quickly and so clearly that there is absolutely no doubt about what we understand." Or in other words, "Intuition is the undoubted conception of a pure and attentive mind, which comes only from The natural light of reason, which is more certain than deduction itself, because intuition itself is simpler, ..." Intuition has two characteristics: first, the proposition of intuition must be the clearest; second, it (the proposition) must be simultaneously ( rather than sequentially), to be understood as a whole.Therefore, we should use intuition as we use our eyes, and we should not disperse our thoughts on all things, but concentrate on a certain point.He who tries to see everything at a glance sees nothing clearly, and if he tries to concentrate on many things at once in a single act of thought, his thoughts will inevitably be confused; At a certain point, an ability to distinguish various small and delicate objects is acquired through practice. Descartes regards deduction as "the supplementary method of knowing, that is, knowing by deduction. We regard deduction as all necessary inferences originating from other facts that we do know."Deduction does not require proofs that are immediately presented, as intuition possesses, and its certainty is rather given to it to some extent by memory.It reaches its conclusion by a series of indirect arguments, just as we know the last link of a long chain by holding the first link. That is to say, intuition is only as a direct way of knowing, while deduction is an indirect way of knowing through reasoning.Intuition and deduction are the fundamental methods of understanding things, and they are the essence and core of Descartes' method, "except for those self-evident intuitions and inevitable deduction, human beings have no direct access to definite knowledge."In short, intuition is to find the simplest, unquestionable, and undefensible elements of human knowledge, that is, to find the simplest and most reliable concepts or principles.Then deductive reasoning is carried out on them, and all the certain and reliable knowledge are derived. (3) The rules of method According to the starting point of the above-mentioned methodology, Descartes stipulated the rules of method.In his book "Rules for the Guidance of the Mind", Descartes listed twenty-one rules, but in the bibliography of "Introduction to Method", he listed only four, which we can summarize as follows: Rule 1: Never recognize Anything is true unless I know it is true. The first rule tells people to play it safe and avoid negligence and prejudice.Judgment does not go beyond the obvious and clear that things appear to the mind, without any element of doubt.Descartes' so-called obvious is opposite to conjecture, and obvious refers to the results produced in the mind by the facts presented in front of the mind.In traditional terms, intuition is the obvious, and it is the activity of the mind to reach the obvious.Obviously, this rule is based on mathematical intuition, so according to Descartes, it is not an unstable evidence provided by the senses, nor is it a mirage woven by fantasy, but a concept of understanding, which is A single-minded acquisition of pure intellect.This concept is extremely simple and easy, obvious and clear, so that we not only know the content of the object we know, but also understand the content we know.In other words, it is to understand the existence of this concept without any possibility of doubt.Intuition is the way the intellect uses to grasp its point of view, and it is a purely intellectual act.The so-called (clearity) and (Distinction) are the two obvious or intuitive features. "Ming" means that an idea presents itself thoroughly in the intellect to the mind's eye looking at it, without concealing anything. "Clearness" refers to an idea that shows itself to be different from other ideas because the factors it contains are quite different from the factors contained in other ideas.Therefore, "clear" affirms "ming", but "ming" is not necessarily "clear", and "clear" is particularly related to the simplicity of concepts. So, we can simply say: Clarity is the fundamental act of the mind, which Descartes called intuition.In The Search for the Rules of the Mind he lists it next to deduction as the only activities of the intellect.At the same time, intuition is also a clear act, the self-perspective of the mind. Rule Two: Break down each problem we are going to examine into as many parts as possible, as the key to their proper interpretation. In the last rule, Descartes has implied that all difficult problems are difficult because of their complexity.If a difficult problem is analyzed into thousands of tiny parts and simplified, the difficult problem will not become a difficult problem.Since Descartes was convinced that the simple is also obvious, this rule, on the one hand, invites us to ascertain the place and extent of the difficulty; For once the absolute part of the problem is discovered, the answer is there. The main task of analysis is to find the simplest thing, the simplest fact or proposition.This is to find the general from the individual, and move from the concrete to the abstract. This process is carried out through the division of concrete things.Finding the simplest thing is the end of the analysis process. 规则三：依照次序引导我们的思想，由最简单、最容易认识的对象开始，一步一步地上升到最复杂的知识。把全部事物看作是一个从绝对到相对、从简单到复杂、相互依赖、相互联系、层层隶属的有顺序的系列，认识以最简单的事物为起点，“然后，一步一步地前进，探询其它的真理是否能从这个真理中推演出来，并且另外一些真理又从这些结论推演出来，等等，这样依次进行下去”。这条规则是根据这样一个信念：假定一切事物皆有一种程序。如果不能在事物本身找出一种自然的程序，至少也应当给它构想出一种逻辑的程序。这样，分析与综合兼用才是完美齐全。因为综合的原则是：先确定定义和公理，然后借助几何式的证明程序，由单纯的定义和公理到达复杂的知识。综合与分析原先是我们认识事物的两种程序：分析是倒溯的程序，旨在说明复杂观念是由许多其它单纯观念所组成；综合是前进的程序，旨在证明单纯观念能与其它单纯观念组合而成为另一种观念。这两种认识的程序彼此有密切的关系。分析的最后元素是综合的最先元素，当一个观念不能再分析时，就是分析的终极。同样地，当一个观念不能再容纳其它观念的组合时，就是综合到了饱和点。这两种观念是从数学中提取的，但是他们在数学中的应用和在哲学中的应用很不相同。数学中的分析与综合是分开应用的，而在哲学中，则两者应当联合运用而成为一种程序，因为如果一物不是综合的，则它不能有分析。如果一物不能分析，则它没有综合的存在。此外，在分析中，我们假定单纯的才是明显的，复杂的则是有疑问的，所以是由不明显推演到明显，也就是由不知到达知。把那些不为所知的最后元素当作已知，把已知的最先综合当作不知。在综合中，我们同样假定单纯的才是明显的，复杂的则是有疑问的，不过它是由明显变为不明显，所以把那已知的最初元素当作知，而把那些不知的最后综合当作不知。 规则四：处处做周全无误的核算与普遍不漏的检查，直到足够保证没有遗漏任何一件为止。这条规则的设立，是为了辅助分析与综合的应用。它包含检验综合的步骤和清点校核分析的部分，使在演绎时严格地遵守演绎的连贯性，不使其有越级的情形发生以保证真理的明晰和必然。 所以，详细列出那些和问题有关的全部事实，无一遗漏，就可以保证推理的正确性。笛卡尔说：“如果我们希望使我们的科学完善……列举也是很需要的。”从确实性来说，列举尽管不如直观，但还是能够使我们对吸引我们注意力的东西作出正确的、确实的判断。通过列举“我们可能获得比通过其它任何类型的论证(简单的直观除外)所能获得的更确实的结论”。我们的心灵应该满足于这种确实性。 (四)方法论的应用任何方法都是为体系服务的，虽然有时常见体系是荒谬的，方法都是卓越的或颇有可取之处。笛卡尔力求以他的体系把自然科学和数学这两个互相依存而又互相有别的领域结合起来，用玄学思辨把二者统一为一个模式。这是一把钥匙。他的方法论探求的就是怎样才能掌握这把钥匙，意图教给世人的也是如何运用他所认为的这把万能钥匙。事实上，假如我们识破了并且把握住这个特异之处，也就是掌握了笛卡尔方法的奥秘。任何一种方法的确立和发展，只要它不是胡拼乱凑、欺世盗名，只要它确实遵循严谨的、确定的逻辑推演系列，堪称一种方法论而无愧，那么，往往不一定始终准确依据体系来为它规定轨道，它甚至可以与它原来的出发点背道而驰。米纳娃一旦从她父亲朱庇特头脑中全副武装蹦了出来，她的生命归她自己所有，证实她的力量是她自己的行为。唯心主义体系需要的方法，理应适合自身体系的根本要求，即精神、思想、观念是第一性的。但是笛卡尔在他的形而上学领域和他所认为的普遍科学——数学领域内都是从既有的事实出发，根据当时已有的条件，按照“存在于事物本身的秩序”，或者按照“我们凭借思维巧妙铸造的秩序”，探求真理并取得出色的成就。在哲学领域内，他也以同样的方式探求出不仅仅是个别真理，而是达到真正符合上述两种秩序的普遍真理，我们应特别重视他在认识论和方法论方面辩证法运用的实例。 强调科学之间密切联系是笛卡尔一贯的思想。这就是说，不可以把我们考察的对象，包括自然科学各门对象，割裂开来逐一研究，而应该看到一切科学彼此密切联系，“把它们统统完整地学到手，比把它们互相割裂开来更为方便得多”。“因此，谁要是决心认真探求事物真理，他就必须不选择某一特殊科学：因为事物都是互相联系、彼此依存的。”笛卡尔在晚年的一封信中，回顾他学习和研究人生时说：“几何学家达到最困难证明时使用的那些简单容易的推理系列，当时已使我想象：人类认识的一切对象都是这样互相依存的，只要我们力求避免作出错误的推断，遵守一事物至另一事物前后相继的秩序，那就没有什么东西远不可及，也没有什么东西隐而不露，不为我们发现。” 笛卡尔与当时的以及以后的一切哲学革新家一样，要求砸烂已经陈腐的使人窒息的法则桎梏，使我们的睿智从任何成见定规中解放出来，只依从理性光芒的指引去探求事物的真理。理性的光芒不是指向早已作古的先哲，而是指向现时的权威，首先指向那些发展古人遗训中反动方面并且使之成为僵死教条、甚至成为可以使人肉体消灭的刑律的经院哲学。为此，笛卡尔决心彻底地对一切知识，做一次地地道道的怀疑。但是笛卡尔的怀疑应该说是纯理论与方法的怀疑，和怀疑派的怀疑观显然有很大的出入：前者是出于对真理的信心，而后者则是对真理失望所致。笛卡尔怀疑“是谋求保证我自己，抛弃流动的泥沙，寻找岩石与粘土”。