The Scientific Outlook

Bertrand Russell

• Publisher: Routledge
• Year: 2009
• ISBN:
  9781134025930
• Edition: 1
• Topic: Philosophy
• Subtopic: Philosophy History & Theory

According to Bertrand Russell, science is knowledge; that which seeks general laws connecting a number of particular facts. It is, he argues, far superior to art, where much of the knowledge is intangible and assumed. In The Scientific Outlook, Russell delivers one of his most important works, exploring the nature and scope of scientific knowledge, the increased powerover nature that science affords and the changes in the lives of human beings that result from new forms of science. Insightful and accessible, this impressive work sees Russell at his very best.

Part I

Scientific Knowledge

1
EXAMPLES OF SCIENTIFIC METHOD

I. GALILEO

Scientific method, although in its more refined forms it may seem complicated, is in essence remarkably simple. It consists in observing such facts as will enable the observer to discover general laws governing facts of the kind in question. The two stages, first of observation, and second of inference to a law, are both essential, and each is susceptible to almost indefinite refinement; but in essence the first man who said “fire burns” was employing scientific method, at any rate if he had allowed himself to be burnt several times. This man had already passed through the two stages of observation and generalization. He had not, however, what scientific technique demands—a careful choice of significant facts on the one hand, and, on the other hand, various means of arriving at laws otherwise than by mere generalization. The man who says “unsupported bodies in air fall” has merely generalized, and is liable to be refuted by balloons, butterflies, and aeroplanes; whereas the man who understands the theory of falling bodies knows also why certain exceptional bodies do not fall.

Scientific method, simple as it is in essence, has been acquired only with great difficulty, and is still employed only by a minority, who themselves confine its employment to a minority of the questions upon which they have opinions. If you number among your acquaintances some eminent man of science, accustomed to the minutest quantitative precision in his experiments and the most abstruse skill in his inference from them, you will be able to make him the subject of a little experiment which is likely to be by no means unilluminating. If you tackle him on party politics, theology, income tax, house-agents, the bumptiousness of the working-classes and other topics of a like nature, you are pretty sure, before long, to provoke an explosion, and to hear him expressing wholly untested opinions with a dogmatism which he would never display in regard to the well-founded results of his laboratory experiments.

As this illustration shows, the scientific attitude is in some degree unnatural to man; the majority of our opinions are wish-fulfilments, like dreams in the Freudian theory. The mind of the most rational among us may be compared to a stormy ocean of passionate convictions based upon desire, upon which float perilously a few tiny boats carrying a cargo of scientifically tested beliefs. Nor is this to be altogether deplored: life has to be lived, and there is no time to test rationally all the beliefs by which our conduct is regulated. Without a certain wholesome rashness, no one could long survive. Scientific method, therefore, must, in its very nature, be confined to the more solemn and official of our opinions. A medical man who gives advice on diet should give it after full consideration of all that science has to say on the matter, but the man who follows his advice cannot stop to verify it, and is obliged to rely, therefore, not upon science, but upon his belief that his medical adviser is scientific. A community impregnated with science is one in which the recognized experts have arrived at their opinions by scientific methods, but it is impossible for the ordinary citizen to repeat the work of the experts for himself. There is, in the modern world, a great body of well-attested knowledge on all kinds of subjects, which the ordinary man accepts on authority without any need for hesitation; but as soon as any strong passion intervenes to warp the expert’s judgment he becomes unreliable, whatever scientific equipment he may possess. The views of medical men on pregnancy, child-birth, and lactation were until fairly recently impregnated with sadism. It required, for example, more evidence to persuade them that anæsthetics may be used in child-birth than it would have required to persuade them of the opposite. Anyone who desires an hour’s amusement may be advised to look up the tergiversations of eminent craniologists in their attempts to prove from brain measurements that women are stupider than men.¹

It is not, however, the lapses of scientific men that concern us when we are trying to describe scientific method. A scientific opinion is one which there is some reason to believe true; an unscientific opinion is one which is held for some reason other than its probable truth. Our age is distinguished from all ages before the seventeenth century by the fact that some of our opinions are scientific in the above sense. I except bare matters of fact, since generality in a greater or less degree is an essential characteristic of science, and since men (with the exception of a few mystics) have never been able wholly to deny the obvious facts of their everyday existence.

The Greeks, eminent as they were in almost every department of human activity, did surprisingly little for the creation of science. The great intellectual achievement of the Greeks was geometry, which they believed to be an a priori study proceeding from self-evident premises, and not requiring experimental verification. The Greek genius was deductive rather than inductive, and was therefore at home in mathematics. In the ages that followed, Greek mathematics were nearly forgotten, while other products of the Greek passion for deduction survived and flourished, notably theology and law. The Greeks observed the world as poets rather than as men of science, partly, I think, because all manual activity was ungentlemanly, so that any study which required experiment seemed a little vulgar. Perhaps it would be fanciful to connect with this prejudice the fact that the department in which the Greeks were most scientific was astronomy, which deals with bodies that only can be seen and not touched.

However that may be, it is certainly remarkable how much the Greeks discovered in astronomy. They early decided that the earth is round, and some of them arrived at the Copernican theory that it is the earth’s rotation, and not the revolution of the heavens, that causes the apparent diurnal motion of the sun and stars. Archimedes, writing to King Gelon of Syracuse, says: “Aristarchus of Samos brought out a book consisting of some hypotheses of which the premises lead to the conclusion that the universe is many times greater than that now so called. His hypotheses are that the fixed stars and the sun remain unmoved, that the earth revolves about the sun in the circumference of a circle, the sun lying in the centre of the orbit.” Thus the Greeks discovered not only the diurnal rotation of the earth, but also its annual revolution about the sun. It was the discovery that a Greek had held this opinion which gave Copernicus courage to revive it. In the days of the Renaissance, when Copernicus lived, it was held that any opinion which had been entertained by an ancient might be true, but an opinion which no ancient had entertained could not deserve respect. I doubt whether Copernicus would ever have become a Copernican but for Aristarchus, whose opinion had been forgotten until the revival of classical learning.

The Greeks also discovered perfectly valid methods of measuring the circumference of the earth. Eratosthenes the Geographer estimated it at 250,000 stadia (about 24,662 miles), which is by no means far from the truth.

The most scientific of the Greeks was Archimedes (257–212 B.C.). Like Leonardo da Vinci in a later period, he recommended himself to a prince on the ground of his skill in the arts of war, and like Leonardo he was granted permission to add to human knowledge on condition that he subtracted from human life. His activities in this respect were, however, more distinguished than those of Leonardo, since he invented the most amazing mechanical contrivances for defending the city of Syracuse against the Romans, and was finally killed by a Roman soldier when that city was captured. He is said to have been so absorbed in a mathematical problem that he did not notice the Romans coming. Plutarch is very apologetic on the subject of the mechanical inventions of Archimedes, which he feels to have been hardly worthy of a gentleman; but he considers him excusable on the ground that he was helping his cousin the king at a time of dire peril.

Archimedes showed great genius in mathematics and extraordinary skill in the invention of mechanical contrivances, but his contributions to science, remarkable as they are, still display the deductive attitude of the Greeks, which made the experimental method scarcely possible for them. His work on Statics is famous, and justly so, but it proceeds from axioms like Euclid’s geometry, and the axioms are supposed to be self-evident, not the result of experiment. His book On Floating Bodies is the one which according to tradition resulted from the problem of King Hiero’s crown, which was suspected of being not made of pure gold. This problem, as everyone knows, Archimedes is supposed to have solved while in his bath. At any rate, the method which he proposes in his book for such cases is a perfectly valid one, and although the book proceeds from postulates by a method of deduction, one cannot but suppose that he arrived at the postulates experimentally. This is, perhaps, the most nearly scientific (in the modern sense) of the works of Archimedes. Soon after his time, however, such feeling as the Greeks had had for the scientific investigation of natural phenomena decayed, and though pure mathematics continued to flourish down to the capture of Alexandria by the Mohammedans, there were hardly any further advances in natural science, and the best that had been done, such as the theory of Aristarchus, was forgotten.

The Arabs were more experimental than the Greeks, especially in chemistry. They hoped to transmute base metals into gold, to discover the philosopher’s stone, and to concoct the elixir of life. Partly on this account chemical investigations were viewed with favour. Throughout the Dark Ages it was mainly by the Arabs that the tradition of civilization was carried on, and it was largely from them that Christians such as Roger Bacon acquired whatever scientific knowledge the later Middle Ages possessed. The Arabs, however, had a defect which was the opposite of that of the Greeks: they sought detached facts rather than general principles, and had not the power of inferring general laws from the facts which they discovered.

In Europe, when the scholastic system first began to give way before the Renaissance, there came to be, for a time, a dislike of all generalizations and all systems. Montaigne illustrates this tendency. He likes queer facts, particularly if they disprove something. He has no desire to make his opinions systematic and coherent. Rabelais also, with his motto: “Fais ce que voudras,” is as averse from intellectual as from other fetters. The Renaissance rejoiced in the recovered liberty of speculation, and was not anxious to lose this liberty even in the interests of truth. Of the typical figures of the Renaissance far the most scientific was Leonardo, whose note-books are fascinating and contain many brilliant anticipations of later discoveries, but he brought almost nothing to fruition, and remained without effect upon his scientific successors.

Scientific method, as we understand it, comes into the world full-fledged with Galileo (1564–1642), and, to a somewhat lesser degree, in his contemporary, Kepler (1571–1630). Kepler is known to fame through his three laws: he first discovered that the planets move round the sun in ellipses, not in circles. To the modern mind there is nothing astonishing in the fact that the earth’s orbit is an ellipse, but to minds trained on antiquity anything except a circle, or some complication of circles, seemed almost incredible for a heavenly body. To the Greeks the planets were divine, and must therefore move in perfect curves. Circles and epicycles did not offend their æsthetic susceptibilities, but a crooked, skew orbit such as the earth’s actually is would have shocked them deeply. Unprejudiced observation without regard to æsthetic prejudices required therefore, at that time, a rare intensity of scientific ardour. It was Kepler and Galileo who established the fact that the earth and the other planets go round the sun. This had been asserted by Copernicus, and, as we have seen, by certain Greeks, but they had not succeeded in giving proofs. Copernicus, indeed, had no serious arguments to advance in favour of his view. It would be doing Kepler more than justice to suggest that in adopting the Copernican hypothesis he was acting on purely scientific motives. It appears that, at any rate in youth, he was addicted to sun-worship, and thought the centre of the universe the only place worthy of so great a deity. None but scientific motives, however, could have led him to the discovery that the planetary orbits are ellipses and not circles.

He, and still more Galileo, possessed the scientific method in its completeness. While much more is known than was known in their day, nothing essential has been added to method. They proceeded from observation of particular facts to the establishment of exact quantitative laws, by means of which future particular facts could be predicted. They shocked their contemporaries profoundly, partly because their conclusions were inherently shocking to the beliefs of that age, but partly also because the belief in authority had enabled learned men to confine their researches to libraries, and the professors were pained at the suggestion that it might be necessary to look at the world in order to know what it is like.

Galileo, it must be confessed, was something of a gamin. When still very young he became Professor of Mathematics at Pisa, but as the salary was only 7½d. a day, he does not seem to have thought that a very dignified bearing could be expected of him. He began by writing a treatise against the wearing of cap and gown in the University, which may perhaps have been popular with undergraduates, but was viewed with grave disfavour by his fellow-professors. He would amuse himself by arranging occasions which would make his colleagues look silly. They asserted, for example, on the basis of Aristotle’s Physics, that a body weighing ten pounds would fall through a given distance in one-tenth of the time that would be taken by a body weighing one pound. So he went up to the top of the Leaning Tower of Pisa one morning with a ten-pound shot and a one-pound shot, and just as the professors were proceeding with leisurely dignity to their respective lecture-rooms in the presence of their pupils, he attracted their attention and dropped the two weights from the top of the tower to their feet. The two weights arrived practically simultaneously. The professors, however, maintained that their eyes must have deceived them, since it was impossible that Aristotle could be in error.

On another occasion he was even more rash. Giovanni dei Medici, who was the Governor of Leghorn, invented a dredging machine of which he was very proud. Galileo pointed out that whatever else it might do it would not dredge, which proved to be a fact. This caused Giovanni to become an ardent Aristotelian.

Galileo became unpopular and was hissed at his lectures—a fate which also befell Einstein in Berlin. Then he made a telescope and invited the professors to look through it at Jupiter’s moons. They refused on the ground that Aristotle had not mentioned these satellites, and therefore anybody who thought he saw them must be mistaken.

The experiment from the Leaning Tower of Pisa illustrated Galileo’s first important piece of work, namely, the establishment of the Law of Falling Bodies, according to which all bodies fall at the same rate in a vacuum and at the end of a given time have a velocity proportional to the time in which they have been falling, and have traversed a distance proportional to the square of that time. Aristotle had maintained otherwise, but neither he nor any of his successors throughout nearly two thousand years had taken the trouble to find out whether what he said was true. The idea of doing so was a novelty, and Galileo’s disrespect for authority was considered abominable. He had, of course, many friends, men to whom the spectacle of intelligence was delightful in itself. Few such men, however, held academic posts, and university opinion was bitterly hostile to his discoveries.

As everyone knows, he came in conflict with the Inquisition at the end of his life for maintaining that the earth goes round the sun. He had had a previous minor encounter from which he had emerged without great damage, but in the year 1632 he published a book of dialogues on the Copernican and Ptolemaic systems, in which he had the temerity to place some remarks that had been made by the Pope into the mouth of a character named Simplicius. The Pope had hitherto been friendly to him, but at this point became furious. Galileo was living at Florence on terms of friendship with the Grand Duke, but the Inquisition sent for him to come to Rome to be tried, and threatened the Grand Duke with pains and penalties if he continued to shelter Galileo. Galileo was at this time seventy years old, very ill, and going blind; he sent a medical certificate to the effect that he was not fit to travel, so the Inquisition sent a doctor of their own with orders that as soon as he was well enough he should be brought in chains. Upon hearing that this order was on its way, he set out voluntarily. By means of threats he was induced to make submission.

The sentence of the Inquisition is an interesting document:

… Whereas you, Galileo, son of the late Vincenzio Galilei, of Florence, aged 70 years, were denounced in 1615, to this Holy Office, for holding as true a false doctrine taught by many, namely, that the sun is immovable in the centre of the world, and that the earth moves, and also with a diurnal motion; also, for having pupils whom you instructed in the same opinions; also, for maintaining a correspondence on the same with some German mathematicians; also for publishing certain letters on the sunspots, in which you developed the same doctrine as true; also for answering the objections which were continually produced from the Holy Scriptures, by glozing the said Scriptures according to your own meaning; and whereas thereupon was produced the copy of a writing, in form of a letter, professedly written by you to a person formerly your pupil, in which, following the hypothesis of Copernicus, you include several propositions contrary to the true sense and authority of the Holy Scriptures; therefore (this Holy Tribunal being desirous of providing against the disorder and mischief which were thence proceeding and increasing to the detriment of the Holy Faith) by the desire of his Holiness and of the Most Eminent Lords Cardinals of this supreme and universal Inquisition, the two propositions of the stability of the sun, and the motion of the earth, were qualified by the Theological Qualifiers as follows:

1. The proposition that the sun is in the centre of the world and immovable from its place is absurd, philosophically false, and formally heretical; because it is expressly contrary to the Holy Scriptures.
2. The proposition that the earth is not the centre of the world, nor immovable, but that it moves, and also with a diurnal action, is also absurd, philosophically false, and, theologically considered, at least erroneous in faith.

But whereas, being pleased at that time to deal mildly with you, it was decreed in the Holy Congregation, held before his Holiness on the twenty-fifth day of February, 1616, that his Eminence the Lord Cardinal Bellarmine should enjoin you to give up altogether the said false doctrine; and if you should refuse, that you should be ordered by the Commissary of the Holy Office to relinquish it, not to teach it to others, nor to defend it; and in default of acquiescence, that you should be imprisoned; and whereas in execution of this decree, on the following day, at the Palace, in the presence of his Eminence the said Lord Cardinal Bellarmine, after you had been mildly admonished by the said Lord Cardinal, you were commanded by the Commissary of the Holy Office, before a notary and witnesses, to relinquish altogether the said false opinion, and, in future, neither to defend nor teach it in any manner, neither verbally nor in writing, and upon your promising obedience you were dismissed.

And, in order that so pernicious a doctrine might be altogether rooted out, not insinuate itself further to the heavy detriment of the Catholic truth, a decree emanated from the Holy Congregation of the Index prohibiting the books which treat of this doctrine, declaring it false, and altogether contrary to the Holy and Divine Scripture.

And whereas a book has since appeared published at Florence last year, the title of which showed that you were the author, which title is The Dialogue of Galileo Galilei, on the two principal Systems of the World—the Ptolemaic and Copernican; and whereas the Holy Congregation has heard that, in consequence of printing the said book, the false opinion of the earth’s motion and stability of the sun is daily gaining ground, the said book has been taken into careful consideration, and in it has been detected a glaring violation of the said order, which had been intimated to you; inasmuch as in this book you have defended the said opinion, already, and in your presence, condemned; although, in the same book, you labour with many circumlocutions to induce the belief that it is left undecided and merely probable; which is equally a very grave error, since an opinion can in no way be probable which has been already declared and finally determined contrary to the Divine Scripture. Therefore, by Our order, you have been cited to this Holy Office, where, on your examination upon oath, you have acknowledged the said book as written and printed by you. You also confessed that you began to write the said book ten or twelve years ago, after the order aforesaid had been given. Also, that you had demanded licence to publish it, without signifying to those who granted you this permission that you had been commanded not to hold, defend, or teach, the said doctrine in any manner. You also confessed that the reader might think the arguments adduced on the false side to be so worded as more effectually to compel conviction than to be easily refutable, alleging, in excuse, that you had thus run into an error, foreign (as you say) to your intention, from writing in the form of a dialogue, and in consequence of the natural complacency which everyone feels with regard to his own subtleties, and in showing himself more skilful than the generality of mankind in contriving, even in favour of false propositions, ingenious and plausible arguments.

And, upon a convenient time being given you for making your defence, you produced a certificate in the handwriting of his Eminence the Lord Cardinal Bellarmine, procured, as you said, by yourself, that you might defend yourself against the calumnies of your enemies, who reported that you had abjured your opinions, and had been punished by the Holy Office; in which certificate it is declared that you had not abjured nor had been punished, but merely that the declaration made by his Holiness, and promulgated by the Holy Congregation of the Index, had been announced to you, which declares that the opinion of the motion of the earth and stability of the sun is contrary to the Holy Scriptures, and, therefore, cannot be held or defended. Wherefore, since no mention is there made of two articles of the order, to wit, the order “not to teach” and “in any manner,” you argued that we ought to believe that, in the lapse of fourteen or six...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• PREFACE BY DAVID PAPINEAU
• PREFATORY NOTE TO THE SECOND EDITION
• INTRODUCTION
• PART I Scientific Knowledge
• PART II Scientific Technique
• PART III The Scientific Society
• NOTES