Part 1

ESSAYS, OR DISCOURSES,

SELECTED FROM THE WORKS OF FEYJOO, AND TRANSLATED FROM THE SPANISH, BY JOHN BRETT, ESQ.

VOLUME THE FOURTH.

LONDON, Printed for the TRANSLATOR:

Sold by H. PAYNE, Pall-Mall; C. DILLY, in the Poultry; and T. EVANS, in the Strand.

MDCCLXXX.

CONTENTS OF THE FOURTH VOLUME.

PHYSICAL PARADOXES page 1

SCEPTICAL PHILOSOPHY 36

THE SHEW OR AFFECTATION OF LEARNING 137

MORAL AND POLITICAL PARADOXES 163

THE GREAT AND MASTERLY AUTHORITY OF EXPERIENCE 226

A DISPLAY OF THE INTELLECTUAL FACULTIES OF THE VARIOUS PEOPLE, WITH REMARKS ON THE TALENTS OF THE DIFFERENT ONES 329

PHYSICAL PARADOXES.

I. The Greek word Paradox, or Paradoxologia, does not properly signify a false or implicatory proposition, but an improbable or incredible one; and therefore, this word is commonly applied to those propositions, which in the eye of the generality of mankind, at first sight seem false and contradictory, and difficult to be assented to; but upon examining them strictly and with attention, appear to be either true or probable. In this discourse, we shall treat of some of the things of this species, which are to be found in the line of natural philosophy.

PARADOX I.

_Elemental Fire is not hot in the highest Degree._

SECT. I.

II. Vulgar physics, distribute the four qualities which are called first, among the four elements, assigning to each element one of them that is intense in the highest degree, and another which approaches, or comes near to the highest. Thus to fire they attribute heat in the highest degree, and dryness which is nearly approaching to the highest. To the air, humidity in the highest degree, and heat near to it. To the water, coldness in the highest degree, and moisture near to it. To the earth, dryness in the highest degree, and coldness near to it. This distribution, which if regulated, not by a nice examination of the nature of things, but only by an imaginary proportion, is exposed to three serious and weighty objections which are started against it by the modern philosophers; and it is only to the proposition that fire is hot in the highest degree, that they have hitherto made no difficulty of assenting; but that is the point I at present mean to controvert.

III. That elemental fire is not hot in the highest degree, may be evinced, by shewing there is another heat which is much greater, and that is the heat of the sun, when its rays are concentrated in a burning-glass. It is certain, that the most vigorous effects and operations of elemental fire, does not come up in any degree of comparison, to those of that most ardent star. This has been proved evidently, by the experiments made with the burning-glass invented and fabricated by Mons. Villete, an eminent artist of Lions in France; a description of which, was printed and published at Liege in 1715, and was afterwards inserted in the Memoirs of Trevoux of the year 1716. The instant the focus of this burning-glass was applied to any sort of wood, be it ever so green or moist, it set it as suddenly in a flame, as elemental fire would do dry tow. In less than a minute, it melted metals which were the most difficult of liquefaction, such as copper, iron, gold, and all minerals in general. The highest operation the chymists have found elemental fire capable of performing, is that of vitrifaction, which is so called from its reducing matter to a species of glass; but the most intense fire, besides its being tardy in this operation, can perform it only on particular subjects; whereas the burning-glass vitrifies in a short time, every kind of matter, tiles, bricks, cement, bones, stones of all sorts, even marble, and porphyry; and what is most extraordinary, it vitrifies those sort of stones also, with which they make the bottoms of furnaces for melting iron ore in, which although they will endure that intense heat for many years together, will begin to dissolve almost immediately, upon applying the focus of the burning-glass to them.

IV. Although this is very wonderful, what we are about to relate is still more so. The analytic resolution of gold, or what is the same thing, the separation or division of its principal component parts, had till then been deemed impossible; for the misers are not more tenacious of hoarding or preserving their gold, than the gold is of preserving its intrinsic texture; for in spite of all the tortures by fire, which the chymists could invent to break this texture, they could never make it lose its original form. Yet notwithstanding the valour of this generous metal, it submitted obediently to the power of the sun exerted through the burning-glass; as if that power to whom it is said to owe its existence, was the only one to which it could bear to be subject.

V. Mons. Homberg, of the Academy Royal of Sciences, was the first who experienced this rare phenomenon, by resolving into smoak, with the focus of the burning-glass, at the Palace Royal at Paris, a great portion of its mass, which this celebrated chymist judged to be the mercurial part of the gold, and when this was gone, the residue which remained, appeared to be a terrestrial matter, mixed with somewhat of sulphur, that afterwards vitrified. So that in the opinion of Mons. Homberg, sulphur, and mercury, together with a portion of earth, is what gold is composed of, and although the two first are by their nature volatile, and capable of being dissipated and divided by the power of fire in all other metals, and in all other mixtures, they in gold are so intimately united, that no other force or influence can separate them, but that of the sun; it follows then, that the heat of the sun is much greater than that of elemental fire, and that this last cannot be hot in the highest degree, which is what we undertook to prove.

PARADOX II.

_The Air ought rather to be esteemed cold, than hot._

SECT. II.

VI. The quality which Aristotle attributes to the air, is cold somewhat under the highest degree, or nearly approaching to the highest degree. Other philosophers, with more foundation of reason, esteem it indifferent to heat and cold; and I, without setting about to combat this second opinion, say it is more reasonable to suppose it cold than hot. Which I shall attempt to demonstrate in the following manner: in order to make a judgement of the qualities appertaining to a particular thing, we should consider it in a state, where it is divested of the influence of any extrinsic agent, by the operations of which it may be affected; the air then so circumstanced, will always be found to be cold; and from thence it should be inferred, that it naturally is cold. The minor of this proposition is proved, by the air being only warm while it is affected by the rays of the sun, and by its being found, that whenever that influence is withdrawn, it becomes cold again, and that it is by so much the more cold, in proportion to the absence of that influence. From whence it is observable, that in the temperate zones, the air is coldest when the nights are long; and that in the sub-polar, and circum-polar ones, it is extremely cold, on account of the influence of the sun being withdrawn from them for the space of six months together; and that when it returns to enlighten them, because of the obliquity of its rays, it still continues cold, far beyond the degree of mediocrity.

VII. Nor is saying that in the absence of the sun, the earth is the agent that cools the air any reply to this; for if this was so, the lower region of the air would be colder than the middle one, as being nearer to the infrigidating cause; but this is contradicted by our experience; for we very commonly see, that the water does not freeze in the lower region, when in the middle one it is frozen into hail in the clouds; and very often also, that which was frozen above, thaws suddenly upon its falling down.

VIII. If it should be objected to this, that Aristotle and the Peripatetics, when they say the air is warm, speak of the elemental air, and not of the air of the atmosphere which is mixed with an infinite number of heterogenous corpuscles, by some of which it may be made cold, and especially by the many nitrous ones with which it is impregnated. To this I answer first, that in the country where I am now writing, there is not the least appearance of the air being nitrous, for that there is not a grain of nitre to be found in the whole country, notwithstanding which, the cold in winter is sometimes pretty sharp. I answer secondly, that we can only talk of the pure elemental air by conjecture, for no mortal has yet ever breathed any of it, nor is it possible that any one ever should, on account of this element being an open expanse, exposed to the inroads of the effluvias of all other bodies; and we should reason upon sensible qualities, by pursuing the thread of palpable experiments; and not by pursuing that of ideal proportions, as Aristotle did in making the division of his elemental qualities; for the Author of nature is not confined to pursuing only such proportions as fall within the compass of our comprehension. This is the false principle, upon which all the Pythagorean and Aristotelic philosophy has proceeded, and with respect to the doctrine of the four elements, that seems to be tainted with the same vice, as I shall shew more fully in another place. All that I shall say at present is, that Aristotle dealt out, and distributed the four qualities among the four elements, as if he had been the absolute master of them all, and could dispose of and arrange them agreeable to his will and pleasure.

PARADOX III.

_Water considered according to its Nature, is rather disposed to be solid, than fluid._

SECT. III.

IX. This may be demonstrated, upon the same principle the antecedent paradox was; remove for any length of time, the interposition of any extrinsic agent that may contribute to warm the water, and it will always be found to be solid, that is, in a frozen state. This then being so, we may conclude, that is the state it is disposed to continue in agreeable to its nature. This is evinced by the sea under the Poles, and in the adjacent parts, being, during the whole six months the sun is absent from them, frozen to such a degree, that after the sun has revisited them, and continued its influence for the other six months, it is never totally thawed; and it is for this reason, that it has always been found impracticable to sail to China by that rout.

X. The water being under this influence, is a proof _ad hominem_, that it cannot, agreeable to the doctrine of Aristotle, be cold in the highest degree, for if that was the case it must ever continue in a frozen state; so that we can only say, that by its nature it is most disposed to solidity.

XI. Frozen water being easily made liquid by a moderate heat, is no proof that it is not naturally inclined to solidity. Metals may be liquified by an intense heat, but that does not shew that they are not of a solid nature; and a thing being more easily, or with more difficulty dissolved, makes no difference with respect to this mode of reasoning; and therefore the water being made liquid with a less intense heat, than is found necessary to liquify metals, does not prove, that it is not disposed in its nature to be solid as well as them.

PARADOX IV.

_Either all Qualities are occult, or none of them are so._

SECT. IV.

XII. The school philosophers call all those qualities occult, which are not reckoned among the four elemental ones, and which do not result from the various combinations of these elemental ones, because they suppose their operations move in a line superior to those which may be supposed to proceed from humidity, dryness, cold, heat, hardness, softness, colour, favour, &c. And although it is true, that some by pursuing the system of assigning second qualities, which result from the various combinations of the first; or third qualities, resulting from the various combinations of the second; and among these third, have placed the wonderful virtues of the load-stone, the operation of purges, and others of those which they call occult, and which by these means they have attempted to reduce to manifest ones; this mode of proceeding, has been abandoned by the generality of philosophers, and with reason; for it is very clear, that combine, and recombine, the qualities of humidity, dryness, heat, and cold, in what way you will, you will not be able to find out, that they are capable of directing the load-stone to the Pole, or of causing it to attract iron.

XIII. It is not my intention, to examine the nature and origin of all, or either of these qualities; but shall only say, that they are all equally occult, or are all equally manifest. In order to demonstrate this, we will compare the calefactive virtue of fire which is looked upon as the most manifest, with the attractive virtue of the load-stone, which is reputed the most occult. All that is known, or that is taught by the peripatetic doctrine, of the calefactory virtues of fire, may be reduced to this, that it is a property appertaining to that substance, or a quality that springs from, or arises out of its form, that produces the effect which we call heat, and that the action with which it causes it, is called calefaction; but so it is, that it is just in the same manner that we know the attractive virtue of the load-stone; _viz._ that it is a property or quality, springing from, or arising out of the form of this entity, that produces the sensible effect of drawing the iron to it, and that the action with which it causes it to approach towards it, is called attraction; it follows then, that we know just as much of the attractive virtue of the load-stone, as we know of the calefactory virtues of fire; and therefore, both of them are equally occult, and equally manifest.

XIV. And if we were to speak the truth, how could we deny, that the quality we call heat is occult, when it is even occult, whether it is or is not a quality? Not only the corpuscular philosophers deny it to be possessed of all quality or form, but many of those who admit those properties to be contained in it, constitute the heat to proceed from a vertical, or vibratory motion of the insensible particles of the body. And so long as we shall remain without an argument to convince us of the truth of these opinions, we shall not know which of them is right.

PARADOX V.

_It is false, in a general and comprehensive sense, that Virtue by being united becomes the stronger._

SECT. V.

XV. The axiom _Vis unita fortior_, I apprehend, applies more justly to civil and political things, than to natural ones. If we attend, we shall find that two agents, each of which is strong in proportion to four, by being joined together, will not be stronger than in proportion to eight. If two men separately can support but four half hundreds each, by joining them together, you would find them not able to support above eight. It is true, that a man who breaks arrows one by one, cannot break a bundle of arrows tied together, which is the comparison that Scilurus availed himself of (Plut. in Apophth.) to persuade his sons to continue in fraternal union; but we should not understand by this, that by binding them together, each arrow separately acquired any additional strength, for this example was only intended to shew, that he who could with ease break each arrow separately, was not sufficiently strong to break the whole bundle united together. Suppose, for instance, the bundle was to consist of twenty arrows, if there was any thing less than a twentieth part of the force exerted to break a single arrow, than it was necessary to exert to break the whole bundle, it is as certain that that single arrow would not be broke, as that the whole bundle would not. Thus this example does not prove, that there is any additional virtue or strength added to the wood of which the arrows are made, by uniting them together, but only, that twenty joined together can resist a greater force than one singly, which is a thing that is self-evident.

XVI. Nothing can be plainer than this; but abstracted from the force of this reasoning, experience has shewn us, that in some agents, in contradiction to the common opinion, their union has diminished their strength. It is the general sentiment, that two threads twisted together and united in one cord, will support more weight than they will separately; and that a rope made of many fine threads, is stronger than all these threads divided. Mons. Reamur, of the Academy Royal of Sciences, demonstrated in 1711, that the fact was quite otherwise, and that the threads separate would support a greater weight than they would united. He made this experiment with two single threads, and found that each by itself would support nine pounds and a half, which put together make nineteen pounds; after this he caused them to be twisted together, and they were broke with sixteen pounds. He made another experiment with three threads, one of which supported six pounds and a half; another eight, and another eight and a half; the sum of all which put together amounted to twenty-three pounds; and after causing them to be made into a cord, they would not sustain more than seventeen.

XVII. It may perhaps be answered to this, that the threads in twisting them together might be stretched and made finer, and their strength weakened; and that besides this, they might have been strained by supporting the weight in the first instance; but this objection, although specious, is insufficient; for by attending to the relation of this matter in the History of the Academy Royal, we shall find, that by order of the Academy, another experiment was made in a quite opposite way, for a small silk cord which supported a little more than five pounds, was afterwards untwisted, and they found that the single threads among them all sustained six pounds and a half.

XVIII. The true cause of this phenomenon in my judgment, is, that the threads in the twisted cord do not bear equally alike, because it seems to me morally impossible in the twisting, to preserve the exact length or bearing of all the fibres, but that some of them must be more tense or tight, and some of them more slack than others; in consequence of which, the bearing of some must vary more from the perpendicular or central line of gravity, than that of the others, and that some part of them are upon the stretch, and others rather slack at one and the same time. From hence it follows, that the weight at first is not supported by all the fibres, but only by those which are the most tense, and the least distant from the central line of gravity, which not being of themselves sufficient to resist the strain, give way, and that the weight afterwards falling upon the others, they do the same; and that this is the case may be evidently seen, by observing when more weight is hung to a rope than it is able to sustain, it does not break instantly, but successively, and although the total separation is performed in a very little time, there is space enough before it is compleated, for us to perceive, that some threads break first, and others afterwards.

XIX. But although my opinion should not exactly coincide with the experiments made in the academy, I conclude, that the judgment we should make of this matter is, that both in this, and all other physical agents, virtue united is the same that it is separate; for the cord breaking with a less weight than the threads sustained separate, did not result from these last being stronger separate than they were united, but from the fibres of the threads acting more together in their separate state, than they did in their united one, as in the last case, the resistance of the fibres to the force, was made more in succession than it was in the first; or to speak more properly, although the threads were united in the cord, their power or virtue of resistance to the force, was not united or exerted together.

PARADOX VI.

_The Sun in consequence of its own proper Nature, and intrinsic Disposition, heats and enlightens unequally at different Times._

SECT. VI.

XX. The common causes of our experiencing more or less heat, or more or less light from the sun, are the serene or loaded state of the atmosphere; the oblique direction with which the sun’s rays are reflected on us; the position, or situation of places; the length or shortness of the days; the tranquillity or agitation of the winds, and our vicinity to cold or warm places, such as snowy mountains, or warm subterraneous effluvia. But, abstracted from any of these sublunary or inferior causes, I say, that in the sun itself, is contained a cause, that occasions it to reflect more or less light or heat, and that it actually does reflect more or less light and heat, at some times than it does at others, and that this is in virtue of its own proper nature and disposition.

XXI. The reason of which phenomenon is, the transitory spots, which the astronomers have for some time past observed in the sun. These are a sort of darkish places, unequal in size and duration, which seem as if they were on the superficies of the star, and which at different times are more or less numerous, although it has happened, that for years together none of them have appeared. Some believe that the antient Chaldeans had some knowledge of them, for in the Book of Job, we read the following expression of Job’s friend Eliphaz to him, that the Heavens themselves are not exempt from their spots: _Cæli non sunt mundi in conspectu ejus._ On the other hand, the want of telescopes among the ancients, did not render their making observations on these things impossible; for some of these spots are so large, as to be visible without a telescope; as for example that was, which was seen in the year 1706, whose superficies according to the computation of the astronomers, was thirty-six times larger than the whole earth; and when they arrive at this magnitude, or if they are even much less, they may be discerned, by looking at the sun with a glass tinged with any dark colour.