CONTENTS

Translators' Preface

Introduction by Vernon J. Bourke

BOOK I. THE PRINCIPLES OF NATURAL THINGS

Lecture 1. The matter and the subject of natural science and of this book. We must proceed from the more universal principles which are better known to us

Lecture 2. The opinions of the ancient philosophers about the principles of nature and of beings. It does not pertain to natural science to disprove some of these opinions

Lecture 3. The assertion of Parmenides and Melissus that all things are one being is refuted

Lecture 4. The later philosophers also were involved in this same error, namely, that the one and the many could not in any way concur

Lecture 5. The argument of Melissus is answered

Lecture 6. The argument of Parmenides is answered in a number of ways

Lecture 7. He disproves the position of those who said that nonbeing is something

Lecture 8. The opinions of the physicists who spoke of the principles as natural philosophers

Lecture 9. The opinion of Anaxagoras that the principles are infinite is refuted

Lecture 10. The opinions of the ancients concerning the contrariety of the first principles

Lecture 11. There are three principles of natural things, no more, no less

Lecture 12. In every coming to be three principles are to be found: the subject, the terminus of the production, and its opposite

Lecture 13. There are two per se principles of the being and of the becoming of natural things, namely, matter and form, and one per accidens principle, namely, privation

Lecture 14. The problems and the errors of the ancients which spring from an ignorance of matter are resolved by the truth about the principles already determined

Lecture 15. Matter is distinguished from privation. Matter is neither generable nor corruptible per se

BOOK II. THE PRINCIPLES OF NATURAL SCIENCE

Lecture 1. What is nature? What things have a nature? What things are 'according to nature'?

Lecture 2. Nature is both matter and form, but primarily form

Lecture 3. How physics and mathematics differ in their consideration of the same thing

Lecture 4. Physics considers not only matter but also every form existing in matter

Lecture 5. Physics determines what the causes are and how many species of causes there are

Lecture 6. Concerning the different modes of causing and those things which are consequent upon these different modes of causing

Lecture 7. Different opinions about fortune and chance, the hidden causes

Lecture 8. After making certain divisions among effects and causes, he concludes to a definition of fortune

Lecture 9. The meaning of the things which the ancient philosophers and the common man say about fortune

Lecture 10. The difference between chance and fortune. The causes are neither more nor less than four

Lecture 11. Natural philosophy demonstrates from all of the four genera of causes

Lecture 12. The argument of those who deny that nature acts for an end

Lecture 13. It is demonstrated that nature acts for an end

Lecture 14. He demonstrates that nature acts for an end from the evidence from which some conclude to the opposite position

Lecture 15. How necessity is found in natural things

BOOK III. MOBILE BEING IN COMMON

Lecture 1. Natural science treats motion and those things which are consequent upon motion. Certain divisions which are necessary for the investigation of the definition of motion

Lecture 2. The definition of motion

Lecture 3. The definition of motion has been well formulated

Lecture 4. Motion is the act of the mobile object as the subject in which and the act of the mover as the cause by which

Lecture 5. Whether action and passion are the same motion

Lecture 6. Physics considers the infinite. The opinions of the ancients concerning the infinite

Lecture 7. Arguments which persuade us that the infinite exists. The meanings of 'infinite'. An infinite separated from sensible things must be denied

Lecture 8. An infinite in act in sensible things cannot be granted. This is shown first with logical arguments, secondly with natural arguments, on the supposition that the elements of bodies are finite in number

Lecture 9. He proves without suppositions that there is no actually infinite sensible body

Lecture 10. The infinite exists, not as being in act, but as being in potency. Different infinites are compared with each other

Lecture 11. The definition of the infinite

Lecture 12. The meanings of things which are said about the infinite

Lecture 13. He answers the arguments which were brought forth in Lecture 7 to show that the infinite exists not only in potency but also in act

BOOK IV. PLACE, VOID AND TIME, THE MEASURES OF MOBILE BEING

Lecture 1. The study of place pertains to natural science. Probable reasons are given to show that place exists

Lecture 2. Six probable arguments are given to show that place does not exist

Lecture 3. He argues whether place is form or matter

Lecture 4. Various ways in which something is said to be in something. Whether something can be in itself. Certain difficulties about the existence and nature of place are answered

Lecture 5. Certain things necessary to investigate the definition of place are set forth

Lecture 6. The definition of place

Lecture 7. What things are in place simply. How that which is not in place simply is in place accidentally

Lecture 8. From the given definition of place the difficulties raised in Lecture 2 are solved, and the nature of the properties of place is established

Lecture 9. The treatment of the void pertains to natural philosophy. Opinions and arguments affirming and denying the existence of the void

Lecture 10. What the word 'void' means. The arguments of those who posit a void are refuted

Lecture 11. It is shown from motion that there is no separated void

Lecture 12. It is shown from the speed and slowness in motion that there is no separated void

Lecture 13. It is shown from the void itself that there is no separated void

Lecture 14. There is no void in bodies

Lecture 15. It is argued whether time exists and whether the same 'now' is in all time

Lecture 16. By means of disputation he inquires what time is and how it is related to motion

Lecture 17. The definition of time is given and explained

Lecture 18. How the same 'now' is or is not in the whole of time. The meaning of things which are said of the 'now'

Lecture 19. Certain things which are usually said about time are clarified

Lecture 20. How motion and other things are in time. What things are and what things are not in time

Lecture 21. He compares time to things which are in the 'now'. The meaning of 'now' (nunc), 'then' (tunc), 'presently' (iam), 'lately' (modo), 'long ago' (olim), and 'suddenly' (repente)

Lecture 22. How corruption is attributed to time. All motion and mutation is in time

Lecture 23. Difficulties concerning the existence and unity of time are answered

BOOK V. THE DIVISION OF MOTION INTO ITS SPECIES

Lecture 1. Motion per se is distinguished from motion per accidens. Only motion per se must be treated

Lecture 2. The species of mutation are established. It is shown which of these species is motion in the strict sense

Lecture 3. There is no motion per se in the categories other than quantity, quality, and where

Lecture 4. He concludes that there is motion only in quantity, quality, and where. He explains how there is motion in these three genera and what he means by 'immobile'

Lecture 5. He defines 'contact', 'succession', 'continuity', and other related things

Lecture 6. The generic, specific, and numerical unity of motion

Lecture 7. More concerning the numerical unity of motion. Two secondary types of unity in motion

Lecture 8. The contrariety of motions

Lecture 9. The contrariety of rest to motion and of rest to rest

Lecture 10. Certain difficulties are answered

BOOK VI. THE DIVISION OF MOTION INTO ITS QUANTITATIVE PARTS

Lecture 1. No continuum is composed of indivisible parts

Lecture 2. If magnitude is composed of indivisible parts, then so is motion. But this is impossible

Lecture 3. The divisibility of time follows from the divisibility of magnitude, and vice versa

Lecture 4. The finite and the infinite are found in both magnitude and time in the same way. It is proven that no continuum is indivisible

Lecture 5. The 'now' of time is indivisible. In the 'now' of time nothing is either moved or at rest. Whatever is moved is divisible. Certain difficulties are answered

Lecture 6. Two ways in which motion is divided

Lecture 7. The part of time in which a thing has first been moved is indivisible. How there can be a first motion

Lecture 8. Before every 'being moved' there is a 'has been moved'. And before every 'has been moved' there is a 'being moved'

Lecture 9. The finite and the infinite are found together in magnitude, time, motion, and the mobile body

Lecture 10. The division of rest and of coming to rest

Lecture 11. The arguments of Zeno, who tried to deny all motion, are answered

Lecture 12. That which is without quantitative parts can be moved only accidentally

Lecture 13. No mutation is infinite in its proper species. How motion can be infinite in time

BOOK VII. THE COMPARISON OF MOVERS AND MOBILE OBJECTS

Lecture 1. Whatever is moved must be moved by another

Lecture 2. Mobile objects and motions cannot proceed to infinity. There must be an immobile first mover

Lecture 3. In local motion the mover and the moved must be together

Lecture 4. In alteration and in increase and decrease the mover and the moved are together

Lecture 5. There is no alteration in the fourth species of quality (form and figure) nor in the first species of quality (habit and disposition) in regard to the body

Lecture 6. There is no alteration in the first species of quality in regard to habits of the soul

Lecture 7. The comparison of motions. He shows in general what is required for things to be comparable

Lecture 8. From the principles established in the preceding lecture he shows which motions are comparable to each other

Lecture 9. Rules for the comparison of motions

BOOK VIII. THE FIRST MOTION AND THE FIRST MOVER

Lecture 1. Whether or not motion began or will end

Lecture 2. Arguments for the eternity of motion

Lecture 3. Arguments against Anaxagoras and Empedocles who held that motion is not eternal

Lecture 4. He answers arguments which seem to prove that motion is not eternal

Lecture 5. Things may be moved or at rest in five ways. The first two ways are dismissed

Lecture 6. It cannot be said that some things are always at rest and all other things are always moved

Lecture 7. Whatever is moved is moved by another

Lecture 8. He explains how heavy and light things are moved

Lecture 9. It is impossible for a thing to be moved by another to infinity. It is not necessary that every mover be moved

Lecture 10. How a thing moves itself

Lecture 11. How the parts of a self-mover are related to each other, and how the whole is said to move itself with respect to them

Lecture 12. The first mover is immobile and one

Lecture 13. The first mover is eternal and immobile. The first motion is eternal

Lecture 14. Local motion is the first motion

Lecture 15. Only local motion can be continuous and eternal

Lecture 16. No local motion other than circular motion can be continuous and eternal

Lecture 17. From the foregoing certain difficulties are answered

Lecture 18. He shows with logical arguments that reflex motion is not continuous

Lecture 19. He shows with proper arguments that circular motion can be continuous and that circular motion is the first motion

Lecture 20. He shows with common and logical arguments that circular motion is continuous and first. According to the opinions of the ancient philosophers local motion is the first motion

Lecture 21. A finite mover cannot move in an infinite time. An infinite power cannot reside in a finite magnitude. A finite power cannot reside in an infinite magnitude

Lecture 22. The problem of projectile motion

Lecture 23. The first mover cannot have magnitude

Appendix A