Introduction to Western Humanities - Baroque & Enlightenment

Selections from Francis Bacon's

the Interpretation of Nature
and the Kingdom of Man
The First Book

There is a Study Guide to accompany this reading.  There is also an introduction to Francis Bacon and a discussion of Bacon's and Descartes' departures from scholasticism in philosophy.

1. Man, being the servant and interpreter of nature, can do and understand so much and so much only as he has observed in fact or in thought of the course of nature; beyond this he neither knows anything nor can do anything.

2. Neither the naked hand nor the understanding left to itself can effect much. It is by instruments and helps that the work is done, which are as much wanted for the understanding as for the hand. And as the instruments of the hand either give motion or guide it, so the instruments of the mind supply either suggestions for the understanding or cautions.

3. Human knowledge and human power meet in one; for where the cause is know known the effect cannot be produced. Nature to be commanded must be obeyed; and that which in contemplation is as the cause is in operation as the rule.

9. The cause and root of nearly all evils in the sciences is this - that while we falsely admire and extol the powers of the human mind we neglect to seek for its true helps.

11. As the sciences which we now have do not help us in finding out new works, so neither does the logic which we now have help us in finding out new sciences.

12. The logic now in use serves rather to fix and give stability to the errors which have their foundation in commonly received notions, than to help the search after truth. So it does more harm than good.

14. The syllogism consists of propositions, propositions consist of words, words are symbols of notions. Therefore if the notions themselves (which is the root of the matter) are confused and overhastily abstracted from the facts, there can be no firmness in the superstructure. Our only hope therefore lies in a true induction.

19. There are and can be only two ways of searching into and discovering truth. The one flies from the senses and particulars to the most general axioms, and from these principles, the truth of which it takes for settled and immovable, proceeds to judgment and to the discovery of middle axioms. And this way is now in fashion. The other drives axioms from the senses and particulars, rising by a gradual and unbroken ascent, so that it arrives at the most general axioms last of all. This is the true way, but as yet untried.

25. The axioms now in use, having been suggested by a scanty and manipular experience and a few particulars of the most general occurrence, are made for the most part just large enough to fit and take these in; and therefore it is no wonder if they do not lead to new particulars. And if some opposite instance, not observed or not known before, chance to come in the way, the axiom is rescued and preserved by some frivolous distinction; whereas the truer course would be to correct the axiom itself.

26. The conclusions of human reason as ordinarily applied in the matter of nature, I call for the sake of distinction Anticipations of Nature (as a thing rash or premature). That reason which is elicited from facts by a just and methodical process, I call Interpretation of Nature.

31. It is idle to expect any great advancement in science from the superinducing and engrafting of new things upon old. We must begin anew from the very foundation, unless we would revolve forever in a circle with mean and contemptible progress.

36. On method of delivery alone remains to us; which is simply this: we must lead men to the particulars themselves, and their series and order; while men on their side must force themselves for awhile to lay their notions by and begin to familiarize themselves with facts.

38. The idols and false notions which are now in possession of the human understanding, and have taken deep root therein, not only so beset men's minds that truth can hardly find entrance, but even after entrance obtained, they will again in the very instauration of the sciences meet and trouble us, unless men being forewarned of the danger fortify themselves as far as may be against their assaults.

39. There are four classes of idols which beset men's minds. To these for distinction's sake I have assigned names, -- calling the first class Idols of the Tribe; the second, Idols of the Cave; the third, Idols of the Market-place; the fourth, Idols of the Theater.

41. The Idols of the Tribe have their foundation in human nature itself, and in the tribe or race of men. For it is a false assertion that the sense of man is the measure of things.  On the contrary, all perceptions, as well of the sense as of the mind, are according to the measure of the individual and not according to the measure of the universe.  And the human understanding is like a false mirror, which, receiving rays irregularly, distorts and discolors the nature of things by mingling its own nature with it.

42. The Idols of the Cave are the idols of the individual man. For everyone (besides the errors common to human nature in general) has a cave or den of his own, which refracts and discolors the light of nature; owing either to his own proper and peculiar nature or to his education and conversation with others; or to the reading of books, and the authority of those whom he esteems and admires; or to the differences of impressions, accordingly as they take place in a mind preoccupied and predisposed or in a mind indifferent and settled; or the like. So that the spirit of man (according as it is meted out to different individuals) is in fact a thing variable and full of perturbation, and governed as it were by chance. Whence it was well observed by Heraclitus that men look for sciences in their own lesser world, and not in the greater or common world.

43. There are also idols formed by the intercourse and association of men with each other, which I call Idols of the Market-place, on account of the commerce and consort of men there. For it is by discourse that men associate; and words are imposed according to the apprehension of the vulgar. And therefore the ill and the unfit choice of words wonderfully obstructs the understanding. Nor do the definitions or explanations wherewith in some things learned men are wont to guard and defend themselves, by any means set the matter right. But words plainly force and overrule the understanding and throw all into confusion, and lead men away into numberless empty controversies and idle fancies.

44. Lastly, there are idols which have immigrated into men's minds from the various dogmas of philosophies, and also from wrong laws of demonstration. These I call Idols of the Theater; because in my judgment all the all the received systems are but so many stage plays, representing worlds of their own creation after an unreal and scenic fashion. Nor is it only of the systems now in vogue, or only of the ancient sects and philosophies, that I speak; for many more plays of the same kind may yet be composed and in like artificial manner set forth; seeing that errors the most widely different have nevertheless causes for the most part alike. Neither again do I mean this only of entire systems, but also of many principles and axioms in science, which by tradition, credulity, and negligence have come to be received.

95. Those who have handled sciences have been either men of experiment or men of dogmas. The men of experiment are like the ant, they only collect and use; the reasoners resemble spiders, who make cobwebs out of their own substance. But the bee takes a middle course; it gathers its material from the flowers of the garden and of the field, but transforms and digests it by a power of its own. Not unlike this is the true business of philosophy; for it neither relies solely or chiefly on the powers of the mind, nor does it take the matter which it gathers from natural history and mechanical experiments and lay it up in the memory whole, as it finds it; but lays it up in the understanding altered and digested. Therefore from a closer and purer league between these two faculties, the experimental and the rational (such as has never yet been made), much may be hoped.

99. Again even in the great plenty of mechanical experiments, there is yet a great scarcity of those which are of most use for the information of the understanding. For the mechanic, not troubling himself with the investigation of truth, confines his attention to those things which bear upon his particular work, and will not either raise his mind or stretch out his hand for anything else. But then only will there be good ground of hope for the further advance of knowledge, when there shall be received and gathered together into natural history a variety of experiments, which are of no use in themselves, but simply serve to discover causes and axioms; which I call experiments lucifera, experiments of light, to distinguish them from those which I call fructifera, experiments of fruit.

Now experiments of this kind have one admirable quality and condition; they never miss or fail. For since they are applied, not for the purpose of producing any particular effect, but only of discovering the natural cause of some effect, they answer the end equally well whichever way they turn out; for they settle the question.

101. But even after such a store of natural history and experience as is required for the work of the understanding, or of philosophy, shall be ready at hand, still the understanding is by no means competent to deal with it offhand and by memory alone. . . .   And yet hitherto more has been done in matter of invention by thinking than by writing; and experience has not yet learned her letters. Now no course of invention can be satisfactory unless it be carried on in writing. But when this is brought into use, and experience has been taught to read and write, better things may be hoped.

102. Moreover, since there is so great a number and army of particulars, and that army so scattered and dispersed as to distract and confound the understanding, little is to be hoped for from the skirmishings and slight attacks and desultory movement of the intellect, unless all the particulars which pertain to the subject of inquiry shall, by means of Tables of Discovery apt, well arranged, and as it were animate, be drawn up and marshalled; and the mind be set to work upon the helps duly prepared and digested which these table supply.

105. In establishing axioms, another form of induction must be devised than has hitherto been employed; and it must be used for proving and discovering not first principles (as they are called) only, but also the lesser axioms, and the middle, and indeed all. For the induction which proceeds by simple enumerations is childish; its conclusions are precarious, and exposed to peril from a contradictory instance; and it generally decides on too small a number of facts, and on those only which are at hand. But the induction which is to be available for the discovery and demonstration of sciences and arts, must analyze nature by proper rejections and exclusions; and then, after a sufficient number of negatives, come to a conclusion on the affirmative instances; which has not yet been done or even attempted, save only by Plato, who does indeed employ this form of induction to a ce4tain extent for the purpose of discussion definitions and ideas. But in order to furnish this induction or demonstration well and duly for its work, very many things are to be provided which no mortal has yet thought of insomuch that greater labor will have to be spent in it than on the syllogism. and this induction must be used not only to discover axioms, but also in the formation of notions. And it is in this induction that our chief hope lies. And this induction must be use not only to discover axioms, but also in the formation of notions. And it is in this induction that our chief hope lies.

119. There will be met with also in my history and experiments many things which are trivial and commonly known; many which are mean and low; many lastly, which are too subtle and merely speculative, and that seem to be of no use; which kind of things may possibly avert and alienate men's interest.

And first for those things which seem common; let men bear in mind that hitherto they have been accustomed to do no more than refer and adapt the causes of things which rarely happen to such as happen frequently; while of those which happen frequently they never ask the cause, but take them for granted. And therefore they do not investigate the causes of weight, of the rotation of heavenly bodies, of heat, cold, light, hardness, softness, rarity, density, liquidity, solidity, animation, inanimation, similarity, dissimilarity, organization, and the like; but admitting these as self-evident and obvious, they dispute and decide on other things of less frequent and familiar occurrence.

But I, who am well aware that no judgment can be passed on uncommon or remarkable things, much less anything new brought to light, unless the causes of common things, and the causes of those causes, be first duly examined and found out, am of necessity compelled to admit the commonest things into my history. Nay, in my judgment philosophy has been hindered by nothing more than this - that things of familiar and frequent occurrence do not arrest and detain the thoughts of men, but are received in passing without any inquiry into their causes; insomuch that information concerning things which are not known is not oftener wanted than attention concerning things which are.


The syllogism consists of propositions, propositions consist of words, words are symbols of notions. There are many different sorts of syllogism. By way of illustration we will focus here on an instance of what is known as the universal affirmative categorical syllogism:

(1) All human beings are rational animals. (2) All cannibals are human beings. Therefore, (3) all cannibals are rational animals.

What Bacon means here by "words" is a bit different from what you might think. In this example, the phrase "human being" is a word, in Bacon's sense of the term. So is the phrase "rational animal." The third word is the word (in our familiar sense of "word" [!]) "cannibal." In other words, the particles "all," "are," and "therefore" are not "words" as Bacon is using the term. We might say that "word" in Bacon's sense here is a "substantive word [our sense] or phrase," a general term (or, in some cases, a proper noun) referring to a class of things (or an individual), even if there don't happen to exist any individual instances of that class (maybe there aren't any cannibals in fact and never have been).

By "notion" Bacon means the concept that a word conveys or "stands for." If we are asked to point to the notion which "cannibal" stands for, we find ourselves in an interesting position. We will probably cast about for another "word" (term) that "means the same thing." That is, we won't be able to produce the notion directly, but will have to point at it by producing a different verbal formula that conveys (Bacon says "symbolizes") the same idea. We say the word "cannibal" stands for a human being who eats the flesh of other human beings. Actually, what we have done is produce another verbal formula (a longer one, "a human being who eats the flesh of other human beings") that (we hope) gives our hearer a clearer recipe for formulating or "constructing" an idea (in his mind) of the notion (something not private to his mind or yours or Bacon's) that the word "cannibal" is presumably carrying, in our example.

In our example, sentences (1), (2) and (3) are what Bacon is terming "propositions" - i.e., assertions, or statements that can be either true or false. (A sentence like "Do squids eat shrimp?" is not a proposition, although both "Squids eat shrimp" and "Squids do not eat shrimp" are propositions. The sentences "I now declare you man and wife" and "You may kiss the bride" and "Please pay the ushers on the way out" are also not propositions in Bacon's sense of the term.)

Sentences (1) and (2) function as premises in the syllogism. Sentence (3) functions as its conclusion. A syllogism is, then, a set of propositions that functions as an argument: it gives us reasons for accepting the conclusion. What sort of reasons? A syllogism combines two sorts: its form and its content. In virtue of its content is says (by asserting the premises) that the premises are true. In virtue of its form, it says that if the premises are true, the conclusion must be true. Syllogisms, unlike propositions, are not "true" or "false." They are, rather, valid or invalid. Whether they are one or the other depends on their form.

To appreciate what we mean by "form" here (our term, not Bacon's), we need to contrast our example with some others with other forms. Consider the following:

Syllogism X.

(1) All human beings are rational animals.
(2) All cannibals are human beings.
(3) all cannibals are rational animals.

Syllogism Y.

(1) All human beings are rational animals.
(4) No rational animals are cannibals..
(5) no cannibals are human beings.

Syllogism Z.

(1) All human beings are rational animals.
(5) No cannibals are human beings.
(4) no rational animals are cannibals.

Syllogism W.

(6) All computers are electronic devices.
(7) All pocket calculators are computers.
(8) all pocket calculators are electronic devices.

Syllogisms X, Y, and Z are all confined to the same notions. But none has the same form. Syllogisms X and W, however, are clearly about quite different subjects. But they share the same form. We can abstract the form from a concrete argument by replacing its terms (what Bacon calls its "words") with variables. We just have to be sure to replace each occurrence of a given term with the same variable. Doing this with our examples, we get

FORM OF Syllogisms W and X.

(1) All A is B.
(2) All C is A.
(3) all C is B.

FORM OF Syllogism Y.

(1) All A is B.
(4) No B is C.
(5) no C is A.
FORM OF Syllogism Z.
(1) All A is B.
(5) No C is A.
(4) no B are C.

It happens that the form of Syllogisms W and X is valid. So is the form of Syllogism Y. But the form of Syllogism Z is invalid. That is, no matter what we substitute for A, B, and C, in the scheme common to Syllogisms W and X, we will always end up with a true conclusion if the premises are true. The same goes for any syllogism with the form embodied in Syllogism Y. With a syllogism of the form we see in Z, however, the case is otherwise: sometimes we get a true conclusion when the premises are true, and sometimes we don't.  Recall the FORM OF Syllogism Z:

(1) All A is B. (5) No C is A. Therefore, (4) no B are C

Contrast the results of the following substitutions:

A = dogs.  B = mammals.  C = squid
A = dogs.  B = mammals.  C = cats

If we come up with even one substitution, in an argument form, that yields true premises with a false conclusion, we have demonstrated that all arguments of that form are invalid: that is, the truth of their premises lends no support whatsoever to the conclusion. (Even if the conclusion happens to be true, that fact is accidental with respect to the premises.) However, demonstrating that an argument form is valid is not so simple: the mere fact that we haven't turned up a concrete example in which the premises are true but the conclusion false doesn't mean by itself mean that we won't in the future: perhaps we just aren't being clever enough in our imaginings.

The Greek philosopher Aristotle (384-322 BC) made a systematic study of the ways in which argument form determines validity in syllogisms, and of the ways in which arguments can sound persuasive but actually be invalid. His achievement was impressive. The six treatises on logic in which he accomplished this are collectively known as the Organon (or "instrument," since logic is a basic tool of learning).  It has been justly influential in the history of philosophy (and in its modern descendants, including the natural sciences), though additional proofs of validity have been devised, and "modern logic," which dates from the work of the English logician George Boole (whose The Mathematical Analysis of Logic appeared in 1847), has introduced a host of new techniques and issues.

But validity is not the only necessary condition for a deductive argument to be sound. Just as it is no good if the premises are true if the form of the argument is invalid, so it is no good if the form of the argument is valid but one of the premises are false! Valid deductive arguments guarantee the truth of the conclusion only if both premises are true. Aristotle of course was perfectly aware of this.  Bacon, however, is convinced that the followers of Aristotle, chiefly among the scholastic philosophers, including those in his own day, do not give enough attention to the problems of assuring the truth of the most general premises (see the next note) in their argument chains. This is why he proposes to write a Novum Organon -- a new guide -- for doing "philosophy," and specifically "natural philosophy," or what we would call "natural science."  He does not propose to replace Aristotle's Organon (that would be silly, since we still need deductive argument!).  Rather, he proposes to supplement it: his aim is to develop the techniques that will enable investigators of nature to arrive at true formulations of natural laws and true causal hypotheses.

He does not altogether succeed in this project. But what is groundbreaking is that he conceives this project, and convinces his audience (over time) of its essentiality and feasibility.  Both the modern science of statistics and sampling, and the ingenuity of countless experimental designs in the natural and social sciences from his day to ours attest to the importance of the way he opens up in the work you are now attempting.


the most general axioms:   By "axiom" here Bacon means "generalization" or "rule" or "law." Generalizations are more or less general according to whether they cover more or fewer particular instances or cases. Thus the claim "human beings can talk" is more general than the claim "all Athenians can talk" (and also the claim "all Athenians love garlic"). If being able to talk is included in being able to think (i.e., if all thinking beings are capable of speech), then the claim "human beings can think" is more general than the claim "human beings can think." Bacon associates both Aristotelianism and Scholasticism with reasoning too confidently via syllogism from highly general principles that have not been carefully established on the basis of prior examination of the sorts of cases they are supposed to cover.


middle axioms:   these would be more specific principles deduced from "the most general axioms." If we know that human beings are rational beings and that cannibals are people, then we can infer the "middle axiom" that cannibals are rational beings.


assertion that the sense of man is the measure of things:   The reference here is to the famous maxim of a 5th-century BC Greek philosopher, Protagoras (c.  490-420 BC): "Man is the measure of all things." Protagoras seems to have had a reputation in his day for agnosticism concerning the existence of the gods, though it may be that he was skeptical rather of the traditionally understood nature of the gods. He may have meant his thesis as an assertion that human reason rather (or, which is something quite different, particular customs of different peoples) are the true standard of morality (instead of the pronouncements or examples of the gods according to traditional lore). Others believe he meant the thesis was meant to convey a radical relativism, i.e., to express the idea that all beliefs (including sensory appearances) are true for whatever individual holds them.


the errors common to human nature in general:   that is, the Idols of the Tribe, just discussed.


Heraclitus:   Another ancient Greek philosopher, who was active c. 500 BC. About a hundred sentences survive (in quotations by other ancient philosophers). They are famously tough nuts to crack, not only because of the fragmentary quality of the remains as a whole but because of their aphoristic style. One of his sayings is that "People step into the same rivers, and different waters flow on to them." Through Plato and Aristotle, Heraclitus came to be associated with the view that "nothing remains the same," that "there is no being, only becoming," - the so-called thesis of "universal flux." Bacon, however, points to Heraclitus here in virtue of a different thesis associated with him.


Tables of Discovery:   Bacon describes and illustrates what he means by "Tables of Discovery" in Aphorisms 10-13 of the Second Book.


the induction which proceeds by simple enumeration: This is one form of what Bacon earlier refers to as a "rash or premature" conclusion (#26) about a general class of things from a small and probably unrepresentative sample of particular instances. (See also #14 on "notions overhastily abstracted from the facts" and the description in #19 of the wrong way to arrive at generalizations.) Suppose I one day attend the Grace Baptist Church over in Columbia, Missouri, and , in talking to some of the deacons there after the service, am appalled to here them griping about people out of work as "parasites" and "scum." I may be tempted to conclude that Baptists are unsympathetic with people in poverty. Bacon goes on to warn, a few lines down, that if we are really concerned to know the truth of the matter, we "must analyze nature by proper rejections and exclusions." Bacon, is of course, speaking of nature; but the same principle applies to our would-be social-science generalization about "the nature of Baptists": we need to be careful to seek out possible negative cases, instances of Baptists who are sympathetic with unemployed people. Clearly, even if I polled the entire congregation of the Grace Baptist Church and found that 90% of them shared these deacons' attitudes, I would still not have a proper basis for concluding that "90% of Baptists are unsympathetic with the poor." Bacon here is hitting on the fundamental problem of induction. The goal is to reach a universal conclusion about a class of things (categorical induction) or, sometimes instead, a conclusion about the probability of a characteristic arising within a whole population of instances (statistical induction). But the job is to reach this conclusion - of the form all A is B (or, in statistical generalization, of the form for all A, the probability that A is B is x% - by looking at only a limited number of A's. It is almost always impracticable to inspect every case we want to pronounce upon.  Indeed, it is in many cases strictly impossible: if we want to know about persons with type O-negative blood, we can't resuscitate those who have died, nor can we examine people who haven't yet been born. We want to know about those dead and those unborns on the basis of what we can find out about (some sample of) people who are alive. And in those relatively rare cases when we can get what statisticians call a "census" - i.e., register every individual in the target population (e.g., all persons who took Dr. Demonic's LSD batch #109)  - we are not making an inductive inference:  whatever universal propositions we are able to make merely summarize the results of past observations.


Aristotle's Organon:  The six treatises that make up this portion of Aristotle's oeuvre are known as Categoriae (The Categories), De interpretation (On Interpretation), Analytica priora (The Prior Analytics), Analytica posteriora (The Posterior Analytics), Topica (The Topics), and Sophistici elenchi (The Refutation of Sophisms, a "sophism" being an argument that often succeeds in persuading the unwary but which in fact is invalid, or fallacious).  


  Go to excerpts from Book II of the Aphorisms concerning the Interpretation of Nature and the Kingdom of Man.

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      From The Philosophical Works of Francis Bacon, transl. Robert Leslie Ellis and James Spedding, 1905.

Notes copyright 1999 by Lyman A. Baker

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      This page last updated 23 September 1999.