Department of History
University of California, Irvine
Instructor:    Dr. Barbara J. Becker

Week 2.  Transmission Trouble

Concerning the Marvelous Power of Art and of Nature and
Concerning the Nullity of Magic (c.1240)

a letter of Roger Bacon (c.1214-1294)
trans. from Latin by Tenney L. Davis (1923)


I am responding to your request.  Even if Nature is powerful and marvelous, yet Art using Nature for an instrument is more powerful by virtue of Nature, as we see in many instances.  Indeed whatever is beyond the operation of Nature or of Art is not human or is a fiction and the doing of fraudulent persons....

Chapter 2

Symbols, Characters, and Magic Practices

What beliefs ought to be held about magic symbols and characters and about similar things is the next matter for my consideration.  For I doubt very much whether all things of this complexion are now false and dubious, for certain of these irrational inscriptions have been written by philosophers in their works about Nature and about Art for the purpose of hiding a secret from the unworthy, so that it should be as if it were wholly unknown--as that lodestone attracts iron, for instance--and someone wishing to achieve his work under the eyes of the multitude might make magic symbols and proffer characters with the intention of representing the force of attraction.  Yet this may be an entirely erroneous interpretation.  Therefore, while many things are hidden by many means in the books of the Philosophers, the wise man ought to be prudent in dealing with them, to the end that he may reject the magic symbols and characters and study the work of Nature and of Art.  Thus animate and inanimate will be seen to concur with Nature, because of the Conformity of Nature, not because of the virtue of magic symbols and characters.  And so, many secrets of Nature and of Art are esteemed magic by the untaught, and Mages stupidly seize upon symbols and characters because they ascribe a virtue to them, and, in the pursuit of them, relinquish the work of Nature and of Art because of the error of magic symbols and characters.  Each class of these men through its own stupidity deprives itself of the use of the others' wisdom.....

Disposition of the Stars

Moreover, men who carry out their affairs according to the face of the heavens and the disposition of the constellations are at liberty to ascribe not only these figures themselves but all of their works as well, directly, to the virtue of Art and of Nature as, less directly, to the virtue of the heavens.  But since it is difficult to perceive the certitude of the heavens, there is much error abut these matters among many people--and there are few who know how to conduct the matter usefully and veraciously.  Because of this the crowd of Mathematicians who judge and act according to magic stars accomplish but little, while those who are well-skilled and understand the art sufficiently may be able, at chosen times, to do many useful things both in act and in judgment.

Charms in Medical Practice

These matters, however, are worthy of consideration to this extent, that a skilled doctor, or any other who has some art to practice, is able to apply symbols and characters (by which is understood fictions) usefully (according to the manner of Constantine, the Physician), not because these characters and symbols are really efficacious in themselves but in order that the medicine may be taken more faithfully and with greater avidity and that the spirit of the patient shall be active and shall later settle and be glad, and that the active spirit shall be able to bring about many renovations in the body which properly appertains to it--so that by gladness and confidence it convalesces from infirmity to health.  If therefore a doctor, for the improvement of his work, in order to excite the patient to the hope and confidence of health, does anything of this sort, it is not to be regarded as something which is done because it is efficacious in itself (if we believe Constantine, the Physician) nor to be despised as a fraud.  For Constantine himself in his letter Concerning Charms which are Hung about the Neck concedes symbols and characters to the neck, and defends them for this use.  The spirit is powerful mightily over its body through its strong effections, as Avicenna teaches in his book de Anima and in that de Animalibus, and as all wise men agree.  Games and plays are effective against infirmities, and delectable dishes are offered to whatever appetite rejects plain food.  Wherefore the mental state triumphs, and desire of spirit is hope over disease.....

Chapter 4

Natural Marvels

Now that these matters are understood, I shall tell of certain marvels wrought through the agency of Art and of Nature, and will afterwards assign them to their causes and modes.  In these there is no magic whatsoever, because, as has been said, all magical power is inferior to these works and incompetent to accomplish them.  First, then, of mechanical devices.

Mechanical Devices

It is possible that great ships and sea-going vessels shall be made which can be guided by one man and will move with greater swiftness than if they were full of oarsmen.

It is possible that a car shall be made which will move with inestimable speed, and the motion will be without the help of any living creature.  Such, it is thought, were the currus falcati which the ancients used in combat.

It is possible that a device for flying shall be made such that a man sitting in the middle of it and turning a crank shall cause artificial wings to beat the air after the manner of a bird's flight.

Similarly, it is possible to construct a small-sized instrument for elevating and depressing great weights, a device which is most useful in certain exigencies.  For a man may ascend and descend, and may deliver himself and his companions from peril of prison, by means of a device of small weight and of a height of three fingers and a breadth of four.

It is possible also easily to make an instrument by which a single man may violently pull a thousand men toward himself in spite of opposition, or other things which are tractable.

It is possible also that devices can be made whereby, without bodily danger, a man may walk on the bottom of the sea or of a river.  Alexander used these to observe the secrets of the sea, as Ethicus the astronomer relates.

These devices have been made in antiquity and in our own time, and they are certain.  I am acquainted with them explicitly, except with the instrument for flying which I have not seen.  And I know no one who has seen it.  But I know a wise man who has thought out the artifice.  Infinite other such things can be made, as bridges over rivers without columns or supports, and machines, and unheard of engines.

Chapter 5

Optical Phenomena and Devices.

Certain physical figurations are especially marvelous, for mirrors and perspective devices can be so arranged that one appears many, one man an army, and the sun and moon as many as we wish.  So, mists and vapors sometimes occur in such manner that two suns, or even three, or two moons, appear simultaneously in the heavens, as Pliny narrates in 2 Nat. Histor.  Since one thing by this means may appear to be many or to be infinite in number, and since it thus actually exceeds its own virtue, then there is no number that is determinate, as Aristotle argues in the chapter de vacuo.  By this means infinite terror may be cast upon a whole city or upon an army so that it will go entirely to pieces because of the apparent multitude of the stars or of men congregated about it, especially if there be joined to this device another by which perspectives are contrived so that the most distant objects appear near at hand and vice-versa.

We may read the smallest letters at an incredible distance, we may see objects however small they may be, and we may cause the stars to appear wherever we wish.  So, it is thought, Julius Caesar spied into Gaul from the sea shore and by optical devices learned the position and arrangement of the camps and towns of Brittany.  Devices may be so contrived that the largest objects appear smallest, that the highest appear low and infamous, and that hidden things appear manifest.  Just as Socrates discovered the hiding-place among the hills of a dragon who was corrupting the city and region roundabout with his breath and pestilential influence, so may all that is going on in a city or in a hostile army be learned from the enemy.

Devices may be built to send forth poisonous and infectious emanations and influences wherever a man may wish.  Aristotle taught this to Alexander, so that by casting the poison of the basilisk over the walls of a city which held out against his army he conveyed the poison into the city itself.

Mirrors may be so arranged that a man coming into a house shall really see gold, and silver, and precious stones, and whatever a man desires, but whoever approaches the place will find nothing.

But of sublimer powers is that device by which rays of light are led into any place that we wish and are brought together by refractions and reflections in such fashion that anything is burned which is placed there.  And these burning glasses function in both directions, as certain authors teach in their books.

The greatest of all devices, however, and the greatest of all things which have been devised is that in which the heavens are described, according to longitude and latitude, with models which actually go through the diurnal movement.  This device is worth more than a kingdom to a wise man....

Chapter 6

Incendiary Compositions.

In addition to these marvels, there are certain others which do not involve particular constructions.  We can prepare from saltpeter and other materials an artificial fire which will burn at whatever distance we please.  The same may be made from red petroleum and other things, and from amber, and naphtha, and white petroleum, and from similar materials.  Pliny reports in his second book that he defended a certain city against the Roman Army, and, by throwing down many incendaries, burned the soldiers in spite of their armor.  Greek Fire and many other combustibles are closely akin to these mixtures.

Further:  perpetual lamps may be made, and baths which retain their heat forever, for we know of substances which are not burned by fire but which are purified.


Beyond these are still other stupendous things in Nature.  For the sound of thunder may be artificially produced in the air with greater resulting horror than if it had been produced by natural causes.  A moderate amount of proper material, of the size of the thumb, will make a horrible sound and violent corruscation.  Such material may be used in a variety of ways, as, for instance, in a case similar to that in which a whole army and city were destroyed by means of the strategy of Gideon who, with broken jugs and torches, and with fire leaping forth with ineffable thunder, routed the army of the Midianites with three hundred men.  These are miracles, if accepted according to their account in size and in substance.

I mention many wonders of another sort, which, though they may have no usefulness, still provide an ineffable spectacle of wisdom and can be applied to inquiring into all those occult matters which the unlearned crowd disbelieve.  They are similar to the attraction of iron by the lodestone:  for who would believe this attraction unless he should actually see it?  There are many wonders of Nature which are not known to the crowd in this attraction of iron, as experience teaches the solicitous inquirer.

But there are still more and still greater than these.   For similarly there is an attraction of all metals by the stone of silver and gold.  A stone thus runs to vinegar, plants mutually seek one another, and the locally divided parts of animals concur in a natural movement.  After I have perceived these things, there is nothing that I find difficult to believe when I reflect that it is either divine or human in its origin.

Self-Activated Working Model of the Heavens

But there are greater than these.  The great power of mathematics can build a spherical instrument, like the artifice of Ptolemy in Almagest, in which all heavenly bodies are described veraciously as regards longitude and latitude, but to make them move naturally in their diurnal movement is not within the power of mathematics.  A faithful and magnificent experimenter might aspire to construct an instrument of such materials and of such an arrangement that it would move naturally in the diurnal motion of the heavens, a thing which seems possible because many things are determined by the movement of the heavens, such as comets, and the tides of the sea, and other things wholly and in part.  In the presence of this instrument all other apparatus of the Astrologers, whether the product of wisdom or mere vulgar equipment, would cease to count any more.  The treasure of a king would scarcely merit comparison with it....

Chapter 7

Prolongation of Life

The ultimate attainment, in which the whole complement of Art joined with all of the power of Nature is effective, is the prolongation of life for a long time.  Many experiences show moreover that this is possible.  For Pliny tells of a soldier strong in mind and body who lived in his probity beyond the accustomed age of man, concerning whom, when Octavianus Augustus asked what he did that he lived so long, the enigmatic reply was made that he used oil externally and mulsum internally.  Later examples confirm the same opinion.  A farmer who was tilling his field plowed up a golden flask filled with noble liquor, and, judging it to be the dew of heaven, he washed his face and drank with the result that the was renewed in body and spirit and in the goodness of wisdom--and from a ploughman he was made porter to the king of Sicily.  This happened in the time of king Ostus.  And there is a case attested by the evidence of a papal letter, that Almanicus, while a captive among the Saracens, took a medicine through the effect of which he prolonged his life five hundred years.  For the king who held him captive had received his medicine from the ambassadors of the Great King; he was suspicious of it and wished to try it on the captive who was released to him.  The Lady of Tormery in England, while searching for a white hind, found an ointment with which the keeper of the woods anointed his whole body except the soles of his feet--and he lived three hundred years without any corruption save pains and suffering in the feet.  Many of us are well aware in our own times that farmers living without the advice of medical men frequently attain the age of a hundred and sixty years or thereabouts.  The same is also confirmed by the case of animals, like deer, eagles, and serpents, which renew their youth through the virtue of plants and stones.  Accordingly, wise men, stimulated by the case of the animals and judging that a thing conceded to brute animals is possible also for man, have devoted themselves to the study of this secret.  Because of this, Artephius, who wisely studied the forces of animals, stones, etc., for the purpose of learning the secrets of Nature, especially the secret of the length of life, gloried in living for one thousand and twenty-five years.

Care of Health

The possibility of the prolongation of life is confirmed by the consideration that the soul naturally is immortal and capable of not dying.  So, after the fall, a man might live for a thousand years; and since that time the length of life has been gradually shortened.  Therefore it follows that this shortening is accidental and may be remedied wholly or in part.  And if we wish to investigate the accidental cause of this corruption, we shall find that it is not from the heavens nor from anything else except from defects in the care of the health.  In our own life time fathers are corrupt and for this reason produce children of corrupt complexion and constitution, and the children of these in their turn are corrupted from the same cause; the corruption descends from father to children--and the abbreviation of life increases continuously.  But it is not to be inferred that life will continue to be abbreviated forever, for the life of man has been fixed so that in many cases men live three score and ten years and the days thereof are labor and sorrow.

A real remedy against specific corruption might be found if a man from his youth would exercise a complete regulation of his health in all matters pertaining to food and drink, sleep and walking, movement and rest, evacuation, retention, air, and passions of the soul.  For if anyone will observe this regimen from his birth, he will live to the utmost that is permitted by the nature which he has inherited from his parents and will be led to the limit of nature fallen from its original uprightness.  Beyond this he cannot go, for the regimen of health is not a remedy for the corruption of our ancient parents....

Chapter 8

The Wisdom of Keeping Secrets

Now that some few examples of the power of Nature and of Art have been enumerated--in order that we may infer many from few, all from parts, universals from particulars, in order that we may see that it is unnecessary for us to aspire to magic since Nature and Art suffice--I wish to pursue certain singulars in their order and causes and to give their method in particular.   But I recall that secrets of Nature are not committed to the skins of goats and of sheep that anyone may understand them, as Socrates and Aristotle have pointed out, and as the latter says in his liber Secretorum, "He is a breaker of the heavenly seal who communicates the secrets of Nature and of Art," adding that "Many evils follow the man who reveals secrets."  And again in the book Noctium Atticarum de collatione sapientium, "It is stupid to offer lettuces to an ass since he is content with his thistles," and in lib. Lapidum it is written that "The man who divulges mysteries diminishes the majesty of things, and a secret loses its value if the common crowd knows about it."...

Seven Ways of Concealing Secrets

The cause of the obscurity in the writings of all wise men has been that the crowd derides and neglects the secrets of wisdom and knows nothing of the use of these exceedingly important matters.  And, if by chance, any magnificent truth falls to its notice, it seizes upon it and abuses it to the manifold disadvantage of persons and of the community.  A man is crazy who writes a secret unless he conceals it from the crowd and leaves it so that it can be understood only by effort of the studious and wise.  Accordingly, the life of wise men is conducted after this principle, and secrets of wisdom are hidden by a variety of methods.  some are hidden under characters and symbols, others in enigmatical and figurative expressions, as in the case where Aristotle says in his liber Secretorum, "O, Alexander, I wish to show you the greatest of secrets, and it behooves you to conceal this arcanum and to perfect the proposed work of this stone of art which is no stone, which is in every man, and in every place, and in every time, and which is called the goal of all philosophers."  Such expressions are found in many books and sciences, and innumerable writings are obscured in this fashion, so that no one may understand them without his teacher.  Others hide their secrets in a third manner by their method of writing, as by writing with consonants only like the Hebrews, Chaldeans, Syrians, and Arabians, and as the Greeks do, for there is much among them which is obscured in this way.  And there is especially much among the Hebrews, for Aristotle says in the above mentioned book, "God gave then all wisdom long before they were philosophers, and all nations get their principles of philosophy from the Hebrews," and Albumasar in his book Introductorii maloris, and other philosophers, and Josephus in the eighth book Antiquitatum, teach the same thing plainly enough.  Fourthly, the obscuring is produced by intermixing various kinds of letters, for so Ethicus the Astronomer hides his wisdom by writing Hebrew, Greek, and Latin letters in the same word.  Fifthly, authors hide their secrets by means of special letters, devised by their own ingenuity and will, and different from those which are anywhere in use.  This is a most serious impediment, and was used by Artephius in his book de Secretis naturae.  Sixthly, actual letters are not used but other geomantic figures which function as letters according to the arrangement of points and marks--and this method also Artephius used in his science.  Seventhly, there is still a better way of obscuring which is comprehended in the ars notaria which is the art of noting and writing with whatever brevity we wish and with whatever rapidity we desire--and by this means many secrets are hidden in the books of the Latins.

I have judged it necessary to touch upon these ways of concealment in order that I may help you as much as I can.  Perhaps I shall make use of certain of them because of the magnitude of our secrets.

Go to:
  • the "cave parable"  from The Republic (c. 360 BCE), by Plato (428-348 BCE);
  • Quaestiones Naturales [Natural Questions] (c. 1116), by Adelard of Bath (c. 1075-1160); and
  • De Naturis Rerum [On the Nature of Things] (c. 1190), by Alexander Neckam (1157-1217).
Weekly Readings
Lecture Notes