This is the fifth post in the Novum Organum sequence. For context, see the sequence introduction.

We have used Francis Bacon's Novum Organum in the version presented at Translated by and copyright to Jonathan Bennett. Prepared for LessWrong by Ruby.

Ruby's Reading Guide

Novum Organum is organized as two books each containing numbered "aphorisms." These vary in length from three lines to sixteen pages. Titles of posts in this sequence, e.g. Idols of the Mind Pt. 1, are my own and do not appear in the original.
While the translator, Bennett, encloses his editorial remarks in a single pair of [brackets], I have enclosed mine in a [[double pair of brackets]].

Bennett's Reading Guide

[Brackets] enclose editorial explanations. Small ·dots· enclose material that has been added, but can be read as though it were part of the original text. Occasional •bullets, and also indenting of passages that are not quotations, are meant as aids to grasping the structure of a sentence or a thought. Every four-point ellipsis . . . . indicates the omission of a brief passage that seems to present more difficulty than it is worth. Longer omissions are reported between brackets in normal-sized type.

Aphorism Concerning the Interpretation of Nature: Book 1: 53–68

by Francis Bacon

53. The idols of the cave—·my topic until the end of 58·— arise from the particular mental and physical make-up of the individual person, and also from upbringing, habits, and chance events. There are very many of these, of many different kinds; but I shall discuss only the ones we most need to be warned against—the ones that do most to disturb the clearness of the intellect.

54. A man will become attached to one particular science and field of investigation either because •he thinks he was its author and inventor or because •he has worked hard on it and become habituated to it. But when someone of this kind turns to general topics in philosophy ·and science· he wrecks them by bringing in distortions from his former fancies. This is especially visible in Aristotle, who made his natural science a mere bond-servant to his logic, rendering it contentious and nearly useless. The chemists have taken a few experiments with a furnace and made a fantastic science out of it, one that applies to hardly anything. . . .

[In this work ‘chemists’ are alchemists. Nothing that we would recognize as chemistry existed.]

[[We might see Bacon here as claiming that "seeing everything as a nail" can be very harmful.]]

55. When it comes to philosophy and the sciences, minds differ from one another in one principal and fairly radical way: some minds have more liking for and skill in •noting differences amongst things, others are adapted rather to •noting things’ resemblances. The •steady and acute mind can concentrate its thought, fixing on and sticking to the subtlest distinctions; the •lofty and discursive mind recognizes and puts together the thinnest and most general resemblances. But each kind easily goes too far: one by •grasping for ·unimportant· differences between things, the other by •snatching at shadows.

56. Some minds are given to an extreme admiration of antiquity, others to an extreme love and appetite for novelty. Not many have the temperament to steer a middle course, not pulling down sound work by the ancients and not despising good contributions by the moderns. The sciences and philosophy have suffered greatly from this, because these attitudes to antiquity and modernity are not judgments but mere enthusiasms. Truth is to be sought not in •what people like or enjoy in this or that age, but in •the light of nature and experience. The •former is variable, the •latter is eternal. So we should reject these enthusiasms, and take care that our intellect isn’t dragged into them.

57. When you think ·hard and long and uninterruptedly· about nature and about bodies in their simplicity—·i.e. think of topics like matter as such·—your intellect will be broken up and will fall to pieces. When on the other hand you think ·in the same way· about nature and bodies in all their complexity of structure, your intellect will be stunned and scattered. The difference between the two is best seen by comparing the school of Leucippus and Democritus with other philosophies. For the members of that school were so busy with the ·general theory of· particles that they hardly attended to the structure, while the others were so lost in admiration of the structure that they didn’t get through to the simplicity of nature. What we should do, therefore, is alternate between these two kinds of thinking, so that the intellect can become both penetrating and comprehensive, avoiding the disadvantages that I have mentioned, and the idols they lead to.

58. Let that kind of procedure be our prudent way of keeping off and dislodging the idols of the cave, which mostly come from

  • intellectual· favouritism (54),
  • an excessive tendency to compare or to distinguish (55),
  • partiality for particular historical periods (56), or
  • the largeness or smallness of the objects contemplated (57).

Let every student of nature take this as a general rule for helping him to keep his intellect balanced and clear: when your mind seizes on and lingers on something with special satisfaction, treat it with suspicion!

59. The idols of the market place are the most troublesome of all—idols that have crept into the intellect out of the contract concerning words and names [Latin verborum et nominum, which could mean ‘verbs and nouns’; on the contract, see 43]. Men think that their reason governs words; but it is also true that words have a power of their own that reacts back onto the intellect; and this has rendered philosophy and the sciences sophistical and idle. Because words are usually adapted to the abilities of the vulgar, they follow the lines of division that are most obvious to the vulgar intellect. When a language-drawn line is one that a sharper thinker or more careful observer would want to relocate so that it suited the true divisions of nature, words stand in the way of the change. That’s why it happens that when learned men engage in high and formal discussions they often end up arguing about words and names, using definitions to sort them out—thus •ending where, according to mathematical wisdom and mathematical practice, it would have been better to •start! But when it comes to dealing with natural and material things, definitions can’t cure this trouble, because the definitions themselves consist of words, and those words beget others. So one has to have recourse to individual instances. . . .

[[Bacon grokked that misuses of words were a great cause of confusion. He probably would have like the A Human's Guide to Words Sequence. See Where to Draw the Boundary? and 37 Ways That Words Can Be Wrong.]]

60. The idols that words impose on the intellect are of two kinds. (1) There are names of things that don’t exist. Just as there are things with no names (because they haven’t been observed), so also there are names with no things to which they refer—these being upshots of fantastic ·theoretical· suppositions. Examples of names that owe their origin to false and idle theories are ‘fortune’, ‘prime mover’, ‘planetary orbits’, and ‘element of fire’. This class of idols is fairly easily expelled, because you can wipe them out by steadily rejecting and dismissing as obsolete all the theories ·that beget them·.

[[See Empty Labels.]]

(2) Then there are names which, though they refer to things that do exist, are confused and ill-defined, having been rashly and incompetently derived from realities. Troubles of this kind, coming from defective and clumsy abstraction, are intricate and deeply rooted. Take the word ‘wet’, for example. If we look to see how far the various things that are called ‘wet’ resemble one other, we’ll find that ‘wet’ is nothing but than a mark loosely and confusedly used to label a variety of states of affairs that can’t be unified through any constant meaning. For something may be called ‘wet’ because it

  • easily spreads itself around any other body,
  • has no boundaries and can’t be made to stand still,
  • readily yields in every direction.
  • easily divides and scatters itself,
  • easily unites and collects itself,
  • readily flows and is put in motion,
  • readily clings to another body and soaks it,
  • is easily reduced to a liquid, or (if it is solid) easily melts.

Accordingly, when you come to apply the word, if you take it in one sense, flame is wet; if in another, air is not wet; if in another, fine dust is wet; if in another, glass is wet. So that it is easy to see that the notion has been taken by abstraction only from water and common and ordinary liquids, without proper precautions.

Words may differ in how distorted and wrong they are. One of the •least faulty kinds is that of names of substances, especially names that

  • are names of lowest species, ·i.e. species that don’t divide into sub-species·, and
  • have been well drawn ·from the substances that they are names of·.

·The drawing of substance-names and -notions from the substances themselves can be done well or badly. For example·, our notions of chalk and of mud are good, our notion of earth bad. •More faulty are names of events: ‘generate’, ‘corrupt’, ‘alter’. •The most faulty are names of qualities: ‘heavy’, ‘light’, ‘rare’, ‘dense’, and the like. (I exclude from this condemnation names of qualities that are immediate objects of the senses.) Yet in each of these categories, inevitably some notions are a little better than others because more examples of them come within range of the human senses.

61. The idols of the theatre ·which will be my topic until the end of 68· are not innate, and they don’t steal surreptitiously into the intellect. Coming from the fanciful stories told by philosophical theories and from upside-down perverted rules of demonstration, they are openly proclaimed and openly accepted. Things I have already said imply that there can be no question of refuting these idols: where there is no agreement on premises or on rules of demonstration, there is no place for argument.


This at least has the advantage that it leaves the honour of the ancients untouched ·because I shall not be arguing against them. I shall be opposing them, but· there will be no disparagement of them in this, because the question at issue between them and me concerns only the way. As the saying goes: a lame man on the right road outstrips the runner who takes a wrong one. Indeed, it is obvious that a man on the wrong road goes further astray the faster he runs. ·You might think that in claiming to be able to do better in the sciences than they did, I must in some way be setting myself up as brighter than they are; but it is not so·. The course I propose for discovery in the sciences leaves little to the acuteness and strength of intelligence, but puts all intelligences nearly on a level. My plan is exactly like the drawing of a straight line or a perfect circle: to do it free-hand you need a hand that is steady and practised, but if you use a ruler or a compass you will need little if anything else; and my method is just like that.


But though particular counter-arguments would be useless, I should say something about •the classification of the sects whose theories produce these idols, about •the external signs that there is something wrong with them, and lastly •about the causes of this unhappy situation, this lasting and general agreement in error. My hope is that this will make the truth more accessible, and make the human intellect more willing to be cleansed and to dismiss its idols.

62. There are many idols of the theatre, or idols of theories, and there can be and perhaps will be many more. For a long time now two factors have militated against the formation of new theories ·in philosophy and science·.

  • Men’s minds have been busied with religion and theology.
  • Civil governments, especially monarchies, have been hostile to anything new, even in theoretical matters; so that men have done that sort of work at their own peril and at great financial cost to themselves—not only unrewarded but exposed to contempt and envy.

If it weren’t for those two factors, there would no doubt have arisen many other philosophical sects like those that once flourished in such variety among the Greeks. Just as many hypotheses can be constructed regarding the phenomena of the heavens, so also—and even more!—a variety of dogmas about the phenomena of philosophy may be set up and dug in. And something we already know about plays that poets put on the stage is also true of stories presented on the philosophical stage—namely that fictions invented for the stage are more compact and elegant and generally liked than true stories out of history!

What has gone wrong in philosophy is that it has attended in great detail to a few things, or skimpily to a great many things; either way, it is based on too narrow a foundation of experiment and natural history, and decides on the authority of too few cases. (1)Philosophers of the reasoning school snatch up from experience a variety of common kinds of event, without making sure they are getting them right and without carefully examining and weighing them; and then they let meditation and brain-work do all the rest. (2) Another class of philosophers have carefully and accurately studied a few experiments, and have then boldly drawn whole philosophies from them, making all other facts fit in by wildly contorting them. (3) Yet a third class consists of those who are led by their faith and veneration to mix their philosophy with theology and stuff handed down across the centuries. Some of these have been so foolish and empty-headed as to have wandered off looking for knowledge among spirits and ghosts. So there are the triplets born of error and false philosophy: philosophies that are (1) sophistical, (2) empirical, and (3) superstitious.

[To explain Bacon’s second accusation against Aristotle in 63: A word ‘of the second intention’ is a word that applies to items of thought or of language (whereas things that are out there in the world independently of us are referred to by words ‘of the first intention’). Now Aristotle in his prime held that the soul is not a substance but rather a form: rather than being an independently existing thing that is somehow combined with the rest of what makes up the man, the soul is a set of facts about how the man acts, moves, responds, and so on. Bacon has little respect for the term ‘form’: in 15 he includes it among terms that are ‘fantastical and ill-defined’, and in 51 he says that ‘forms are fabrications of the human mind’. This disrespect seems to underlie the second accusation; the class of forms is not a class of independently existing things but rather a class of muddy and unfounded ways of thinking and talking, so that ‘form’ is a word of the second intention.]

63. The most conspicuous example of (1) the first class was Aristotle, whose argumentative methods spoiled natural philosophy. He

  • made the world out of categories;
  • put the human soul, the noblest of substances, into a class based on words of the second intention;
  • handled the issues about density and rarity (which have to do with how much space a body takes up) in terms of the feeble distinction between what does happen and what could happen;
  • said that each individual body has one proper motion, and that if it moves in any other way this must be the result of an external cause,

and imposed countless other arbitrary restrictions on the nature of things. He was always less concerned about the inner truth of things than he was about providing answers to questions—saying something definite. This shows up best when his philosophy is compared with other systems that were famous among the Greeks. For

  • the homogeneous substances of Anaxagoras,
  • the atoms of Leucippus and Democritus,
  • the heaven and earth of Parmenides,
  • the strife and friendship of Empedocles, and
  • Heraclitus’s doctrine of bodies’ being reduced to the perfectly homogeneous condition of fire and then remolded into solids,

all have a touch of natural philosophy about them—a tang of the nature of things and experience and bodies. Whereas in Aristotle’s physics you hear hardly anything but the sounds of logical argument—involving logical ideas that he reworked, in a realist rather than a nominalist manner, under the imposing name of ‘metaphysics’. Don’t be swayed by his frequent mentions of experiments in his On Animals, his Problems, and others of his treatises. For he didn’t consult experience, as he should have done, on the way to his decisions and first principles; rather, he first decided what his position would be, and thenbrought in experience, twisting it to fit his views and making it captive. So on this count Aristotle is even more to blame than his modern followers, the scholastics, who have abandoned experience altogether.

64. The (2) empirical school of philosophy gives birth to dogmas that are more deformed and monstrous than those of the sophistical or reasoning school. The latter has as its basis the •light of vulgar notions; it’s a faint and superficial light, but it is in a way •universal, and applies to many things. In contrast with that, the empirical school has its foundation in the •narrowness and •darkness of a few experiments. Those who busy themselves with these experiments, and have infected their imagination with them, find such a philosophy to be probable and all but certain; everyone else finds them flimsy and incredible. A notable example of this ·foolishness· is provided by the alchemists and their dogmas; these days there isn’t much of it anywhere else, except perhaps in the philosophy of Gilbert. Still, I should offer a warning relating to philosophies of this kind. If my advice ever rouses men to take experiments seriously and to bid farewell to sophistical doctrines, then I’m afraid that they may—I foresee that they will—be in too much of a hurry, will leap or fly ·from experiments straight· to generalizations and principles of things, risking falling into just the kind of philosophy I have been talking about. We ought to prepare ourselves against this evil now, ·well in advance·.

65. The corruption of philosophy by (3) superstition and input from theology is far more widespread, and does the greatest harm, whether to entire systems or to parts of them. ·Systems thus afflicted are just nonsense judged by ordinary vulgar standards, but that doesn’t protect men from accepting them, because· the human intellect is open to influence from the imagination as much as from vulgar notions, ·and in these philosophies it is the imagination that wields the power·. Whereas the contentious and sophistical kind of philosophy combatively traps the intellect, this ·superstitious· kind, being imaginative and high-flown and half-poetic, coaxes it along. For men—especially intelligent and high-minded ones—have intellectual ambitions as well as ambition of the will.

A striking example of this sort of thing among the Greeks is provided by Pythagoras, though ·his form of it wasn’t so dangerous, because· the superstition that he brought into it was coarser and more cumbrous ·than many·. Another example is provided by Plato and his school, whose superstition is subtler and more dangerous. Superstition turns up also in parts of other philosophies, when they

  • introduce abstract forms—·i.e. forms that aren’t the forms of anything·,

and when they do things like

  • speaking of ‘first causes’ and ‘final causes’ and usually omitting middle causes.

[Bacon’s point is: They discuss the first cause of the whole universe, and the end or purpose for which something happens (its ‘final cause’), but they mostly ignore ordinary causes such as spark’s causing a fire. Putting this in terms of first-middle-final seems to be a quiet joke].

We should be extremely cautious about this. There’s nothing worse than the deification of error, and it is a downright plague of the intellect when empty nonsense is treated with veneration. Yet some of the moderns have been so tolerant of this emptiness that they have—what a shallow performance!—tried to base a system of natural philosophy on the first chapter of Genesis, on the book of Job, and other parts of the sacred writings, ‘seeking the living among the dead’ [Luke 24:5]. This makes it more important than ever to keep down this ·kind of philosophy·, because this unhealthy mixture of human and divine gives rise not only to •fantastic philosophy but also to •heretical religion. It is very proper that we soberly give our faith only to things that are the faith.

66. So much for the mischievous authority of systems founded on •vulgar notions, on •a few experiments, or on •superstition. I should say something about bad choices of what to think about, especially in natural philosophy. In the mechanical arts the main way in which bodies are altered is by composition or separation; the human intellect sees this and is infected by it, thinking that something like it produces all alteration in the universe. This gave rise to •the fiction of elements and of their coming together to form natural bodies. Another example: When a man surveys nature working freely, he encounters different species of things—of animals, of plants, of minerals—and that leads him smoothly on to the opinion that nature contains certain primary forms which nature intends to work with, and that all other variety comes from •nature’s being blocked and side-tracked in her work, or from •conflicts between different species—conflicts in which one species turns into another. To the first of these theories we owe ·such intellectual rubbish as· first qualities of the elements; to the second we owe occult properties and specific virtues. Both of them are empty short-cuts, ways for the mind to come to rest and not be bothered with more solid pursuits. The medical researchers have achieved more through their work on the second qualities of matter, and the operations of attracting, repelling, thinning, thickening, expanding, contracting, scattering, ripening and the like; and they would have made much greater progress still if *it weren’t for a disaster that occurred. The two short-cuts that I have mentioned (elementary qualities and specific virtues) snared the medical researchers, and spoiled what they did with their correct observations in their own field.

[The passage flagged by asterisks expands what Bacon wrote, in ways that the small-dots system can’t easily indicate.]

It led them either •to treating second qualities as coming from highly complex and subtle mixture of first or elementary qualities, or •to breaking off their empirical work prematurely, not following up their observations of second qualities with greater and more diligent observations of third and fourth qualities.* ·This is a bigger disaster than you might think, because· something like—I don’t say exactly like—the powers involved in the self-healing of the human body should be looked for also in the changes of all other bodies.

But something much worse than that went wrong in their work: they focused on

  • the principles governing things at rest, not on •the principles of change; i.e. on
  • what things are produced from, not •how they are produced; i.e. on
  • topics that they could talk about, not •ones that would lead to results.

The vulgar classification of ·kinds of· motion that we find in the accepted system of natural philosophy is no good—I mean the classification into

  • generation,
  • corruption,
  • growth,
  • diminution,
  • alteration, and
  • motion.

Here is what they mean. If a body is moved from one place to another without changing in any other way, this is •motion; if a body changes qualitatively while continuing to belong to the same species and not changing its place, this is •alteration; if a change occurs through which the mass and quantity of the body don’t remain the same, this is •growth or •diminution; if a body is changed so much that it changes substantially and comes to belong to a different species, this is •generation or •corruption. But all this is merely layman’s stuff, which doesn’t go at all deeply into nature; for these are only measures of motion. . . .and not kinds of motion. They [= the notions involved in the classification into generation, corruption etc.] signify that the motion went this way or that, but not how it happened or what caused it. They tell us nothing about the appetites of bodies [= ‘what bodies are naturally disposed to do’] or about what their parts are up to. They come into play only when the motion in question makes the thing grossly and obviously different from how it was. Even when ·scientists who rely on the above classificatory system· do want to indicate something concerning the causes of motion, and to classify motions on that basis, they very lazily bring in the ·Aristotelian· distinction between ‘natural’ motion and ‘violent’ motion, a distinction that comes entirely from vulgar ways of thinking. In fact, ‘violent’ motion is natural motion that is called ‘violent’ because it involves an external cause working (naturally!) in a different way from how it was working previously.

[Bacon himself sometimes describes a movement as violens, but this is meant quite casually and not as a concept belonging to basic physics. These innocent occurrences of violens will be translated as ‘forceful’.]

Let us set all this aside, and consider such observations as that bodies have an appetite for

mutual contact, so that separations can’t occur that would break up the unity of nature and allow a vacuum to be made;

or for

resuming their natural dimensions. . . ., so that if they are compressed within or extended beyond those limits they immediately try to recover themselves and regain their previous size;

or for

gathering together with masses of their own kind—e.g. dense bodies ·moving· towards the earth, and light and rare bodies towards the dome of the sky.

These and their like are truly physical kinds of motion; and comparison of them with the others that I mentioned makes clear that the others are entirely logical and scholastic.

An equally bad feature of their philosophies and their ways of thinking is that all their work goes into investigating and theorizing about the

  • fundamental· principles of things. . . .—so they keep moving through higher and higher levels of abstraction until they come to formless potential matter—and
  • the ultimate parts of nature—so they keep cutting up nature more and more finely until they come to atoms, which are too small to contribute anything to human welfare—

whereas everything that is useful, everything that can be worked with, lies between ·those two extremes·.

67. The intellect should be warned against the intemperate way in which systems of philosophy deal with the giving or withholding of assent, because intemperance of this kind seems to establish idols and somehow prolong their life, leaving no way open to reach and dislodge them.

There are two kinds of excess: •the excess of those who are quick to come to conclusions, and make sciences dogmatic and lordly; and •the excess of those who deny that we can know anything, and so lead us into an endlessly wandering kind of research. The •former of these subdues the intellect, the •latter deprives it of energy. The philosophy of Aristotle ·is of the former kind·. Having destroyed all the other philosophies in argumentative battle. . . . Aristotle laid down the law about everything, and then proceeded to raise new questions of his own and to dispose of them likewise, so that everything would be certain and settled—a way of going about things that his followers still respect and practice.

The ·Old Academy·, the school of Plato, introduced acatalepsy—·the doctrine that nothing is capable of being understood·. At first it was meant as an ironical joke at the expense of the older sophists—Protagoras, Hippias, and the rest—whose greatest fear was to seem not to doubt something! But the New Academy made a dogma of acatalepsy, holding it as official doctrine. They did allow of some things to be followed as probable, though not to be accepted as true; and they said they didn’t ·mean to· destroy all investigation; so their attitude was better than. . . .that of Pyrrho and his sceptics. (It was also better than undue freedom in making pronouncements.) Still, once the human mind has despaired of finding truth, it becomes less interested in everything; with the result that men are side-tracked into pleasant disputations and discourses, into roaming, rather than severely sticking to a single course of inquiry. But, as I said at the start and continue to urge, the human senses and intellect, weak as they are, should not be •deprived of their authority but •given help.

68. So much for the separate classes of idols and their trappings. We should solemnly and firmly resolve to deny and reject them all, cleansing our intellect by freeing it from them. Entering the kingdom of man, which is based on the sciences, is like entering the kingdom of heaven, which one can enter only as a little child.

Edited: The next post in the sequence, Book 1: 69-92 (13 Causes of Bad Science), will be posted Thursday, October 3rd at latest by 6:00pm PDT.

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I've read all of these so far, but may be you can post them a little less frequently?

Hmm, sure. Let's space them out at like one a week.


Huh, I think we're getting caught between the people who want them more frequently and less. I agree that every 2-days might be a bit much, so yeah, let's go with less. For the enthusiastic, I can note that the full text is already online at