第二讲科技史概要吴国林教授/博士生导师一、古代自然观1、古希腊(Ancient Greek)：世界的本原/基质/始基问题泰勒斯（Thales,约公元前624～公元前547）认为万物本原是水；Everything is made of water.阿那克西曼德(Anaximander公元前610～公元前546)：无限定/无限/阿派朗apeiron阿那克西米尼（Anaximenes, 公元前585～公元前525）认为万物本原是气；air.赫拉克利特（Heraclitus,公元前540～公元前470）认为火是万物本原；Fire is the primordial element. Perpetual change was he believed in.“You cannot step twice into the same river; for fresh waters are ever flowing in upon you.”“The sun is new every day.”留基伯（Leucippus, 约公元前500～公元前440）和他的学生德谟克利特（Democritus, 约公元前460～公元前370）最早提出了原子论(Atomism)观点，认为物质结构是不连续的，由为数极多的原子构成。
古希腊后期的伊壁鸠鲁和古罗马时期卢克莱修继承并发展了原子论思想。
A tom端恩培多克勒：(Empedocles)四元素说（four elements火法），土earth、水water、气air、火fire。
亚里士多德（Aristotle,公元前384～公元前322）认为火、气、水、土四元素是自然界原始物质；5 phases求知乃人之本性。
毕达哥拉斯（Pythagoras,公元前570～公元前500则认为数是万物的本原。
All things are numbers.Some of rules of the Pythagoras order were:Not to eat the heart;Not to pick up what has fallen;To abstain from beans.数的和谐：harmonic mean勾股定理：right-angled triangles: the sum of the squares on the sides adjoining the right angle is equal to the square on the remaining side.电子是什么？怀疑主义：皮罗（Pyrrho,365-275,BC）A . 怀疑论的基本目的：心灵的宁静可以用一个三段式来表达逻辑结构：（1）以“心灵宁静”为目的；（2）以“结束独断”为达到“心灵宁静”的最佳途径；（3）以不可知论为达到“结束独断”的理论基础。
皮罗的最终目标是寻求幸福。
B. 基本方法：反对理论悬搁一切判断。
2、古中国“五行说” （5 phases）（把金、木、水、火、土五种物质看作是构成自然界万物元素，来说明自然界万物的起源和多样性的统一），有阴阳（yin and yang）两种力量two-force theory“元气说”（把“元气”看作是构成天地万物的原始物质）等。
墨子：端Duan老子：道DaoDaoists studied man’s inner life and his relation to nature.宇宙生成论：3、古印度4大元素说：非正统哲学——顺世论提出：地、水、火、风，一切事物都是自然而然的，存在什么创造者。
第二，提出了物质结构问题。
第三，提出了生命起源和生物进化的问题。
例如古希腊阿那克西曼德（公元前610～公元前546）认为生命起源于泥泽，并认为人是由鱼变来的。
此外还提出如天体结构、人体生理结构和功能等问题，其中包含着某些合理成分伯然哲学这一古代科学形态虽然有一定观测事实为依据，但还没有进步到对自然界分析和解剖的地步，对自然联系也没有从细节上加以证明，主要还是靠想象和猜测。
二、古希腊自然科学的贡献古代理论自然科学知识形态。
恩格斯指出：“精确的自然研究只是在亚历山大里亚时期的希腊人那里才开始的。
”一. 亚里士多德Aristotle’s syllogism, Term logic大前提小前提结论All men are mortal (Major premiss).Socrates is a man(Minor premiss).Therefore: Socrates is mortal(Conclusion).“Plato is dear to me, but dearer still is the truth.”----Aristotle哈佛大学校训的原文，是用拉丁文写的，Amicus Plato, Amicus Aristotle, sed Amicus VERITAS，意为“以柏拉图为友，以亚里士多德为友，更要以真理为友”。
哈佛大学的历任校长坚持3A原则，即学术自由、学术自治和学术中立。
The five elementsMain article: Classical element∙Fire, which is hot and dry.∙Earth, which is cold and dry.∙Air, which is hot and wet.∙Water, which is cold and wet.∙Aether, which is the divine substance that makes up the heavenly spheres and heavenly bodies (stars and planets).二. 欧几里得平面几何学。
欧几里得（Euclid, 前450-前380），Euclidean geometryEuclid's Elements of GeometryThe Elements consists of thirteen books. Book 1outlines the fundamental propositions of plane geometry.The Elements consists of thirteen books. Book 1 outlines the fundamental propositions of plane geometry, including the three cases in which triangles are congruent, various theorems involving parallel lines, the theorem regarding the sum of the angles in a triangle, and the Pythagorean theorem. Book 2 is commonly said to deal with ``geometric algebra'', since most of the theorems contained within it have simple algebraic interpretations. Book 3 investigates circles and their properties, and includes theorems on tangents and inscribed angles. Book 4 is concerned with regular polygons inscribed in, and circumscribed around, circles. Book 5develops the arithmetic theory of proportion. Book 6 applies the theory of proportion to plane geometry, and contains theorems on similar figures. Book 7deals with elementary number theory: e.g., prime numbers, greatest common denominators, etc.Book 8 is concerned with geometric series. Book 9 contains various applications of results in the previous two books, and includes theorems on the infinitude of prime numbers, as well as the sum of a geometric series. Book 10 attempts to classify incommensurable (i.e., irrational) magnitudes using the so-called ``method of exhaustion'', an ancient precursor to integration. Book 11deals with the fundamental propositions of three-dimensional geometry. Book 12 calculates the relative volumes of cones, pyramids, cylinders, and spheres using the method of exhaustion. Finally, Book 13investigates the five so-called Platonic solids.Definitions(Book 1)1. A point is that of which there is no part.2. And a line is a length without breadth.3. And the extremities of a line are points.4. A straight-line is (any) one which lies evenly withpoints on itself.5. And a surface is that which has length and breadthonly6. And the extremities of a surface are lines.7. A plane surface is (any) one which lies evenly withthe straight-lines on itself.8. And a plane angle is the inclination of the lines toone another, when two lines in a plane meet one another,and are not lying in a straight-line.9. And when the lines containing the angle arestraight then the angle is called rectilinear.10. And when a straight-line stood upon (another)straight-line makes adjacent angles (which are) equal toone another, each of the equal angles is a right-angle, andthe former straight-line is called a perpendicular to thatupon which it stands.Five Postulates1. Let it have been postulated to draw a straight-line from any point to any point.2. And to produce a finite straight-line continuously in a straight-line.3. And to draw a circle with any center and radius.4. And that all right-angles are equal to one another.5. And that if a straight-line falling across two (other) straight-lines makes internal angles on the same side (of itself whose sum is) less than two right-angles, then the two (other) straight-lines, being produced to infinity, meet on that side (of the original straight-line) that the (sum of the internal angles) is less than two right-angles (and do not meet on the other side).Common Notions1. Things equal to the same thing are also equal to one another.2. And if equal things are added to equal things then the wholes are equal.3. And if equal things are subtracted from equal things then the remainders are equal.4. And things coinciding with one another are equal to one another.5. And the whole [is] greater than the part.公理化体系Father of Geometry公理axiom: 不证自明5条公理第五条：欧几里得（公元前330～公元前275）《几何原本》，总结了几个世纪以来几何学发展成果，从35个原始定义、5条公设和5条公理出发逻辑地证明几何学中的467个定理，建立了几何学的公理化体系。