of this Critique, the poffibility of pure rational knowledge, fuch as Metaphyfics can furnish, has been eftablished. But that knowledge extends no further, than to the world of sense, consequently only to the univerfal and neceffary laws of nature. A demonftrably certain Syftem of Metaphyfics is indeed poffible, but a very different one from what we have had hitherto, which, as its name indicates, fets out with propofitions for judging dogmatically, upon things discoverable beyond the region of Phyfics, i. e. without the limits of Nature.If the principles above delineated be just, the only possible Metaphyfics, so far as we are entitled to proceed doginatically, are the Metaphyfics of Nature.-Confequently the Critique of Kant confiders all the Metaphyfical Systems, which have been hitherto propofed, as false ware, and maintains that we have as yet no just Metaphyfics. His own work is important and profound, and deserves to be carefully examined by those who are converfant in such studies. Whatever the refult of this examination may be, philofophy will undoubtedly gain by it: aud although the Critique of Kant should not stand the teft of future, perhaps more fuccefsful researches, it will nevertheless form a remarkable epoch in the hiftory of Metaphyfical Science.

II. CHRONOLOGICAL ANALYSIS.

Exordium.

In venturing upon this effential part of the Elements, which are defigned to afford a concife, though comprehenfive view of the diverfified labours of KANT, I deem it a duty incumbent upon me to state that, both his fyftematic works *, as well as thofe

* That thefe may be more eafily diftinguished from others, I have arranged them by a fecond number enclosed in ( ).

those which treat upon general fubjects of philosophy, are here fucceffively fubmitted to the confideration of the reader.

I must however remark that, confiftent with the plan and extent of these Elements, the review of fo great a variety of subjects cannot abound in Criticism; but I hope it will be found the more complete in the analytical part of it, comprehending every subject * treated by the illuftrious author, during a period now exceeding half a century.

Though my abilities-the limited compafs of which is best known to myself-were adequate to do the works of KANT that justice in reviewing them critically, to which they are certainly entitled; I would ftill hefitate to engage upon an undertaking, obviously not the most grateful, and in my relative fituation, as a former pupil to the most renowned Profeffor in Europe, perhaps unbecoming. Hence I shall content myself with the humble province of briefly commenting upon the aim of every individual publication, and then of exhibiting the contents of each through a precise translation.

The difficulty of understanding the peculiar terms and expreffions of KANT muft, I have reason to hope, in great meafure vanish; if the reader, in every instance, with patient and diligent application, reforts to the Glossary.

In order to characterize the early genius of the author, who, in the twenty-fecond year of his age, published an Effay upon one of the most abftrufe fubjects of inquiry, I fhall conclude these preliminaries with the fingular Motto prefixed to this juvenile production:

Nihil

* Those Effays, which have not been feparately printed, and the most of which were published in the Monthly Magazine of Berlin, I could not procure from Germany; but I have still introduced them in this review, merely for the fake of completeness, upon the authority of Prof. WILL of Altdorf, and Prof. SCHMID of Jena.

Nihil magis præftandum eft, quam ne pecorum ritu fequamur antecedentium gregem, pergentes, non qua eundum eft, fed qua itur.

SENECA de vita beata; Cap. I.

I. Gedanken von der wahren Schätzung der lebendigen Kräfte.-Reflections upon the true computation of living (moving) powers. Königsberg, 220 pp. large 8vo. with two plates, 1746.

After having paid handsome and due compliments to his meritorious countrymen LEIBNITZ, WOLF, HERRMANN, BERNOULLI, BULLEINGER, and many other eminent philofophers, the young author examines the different theories and proofs advanced" on the living (inherent) powers of bodies," and endeavours to fhew, that their notions on this intricate fubject were far from being correct, and that the diffentions prevailing among them arose chiefly from having, each of them, confidered the fubject in a different point of view. Thus their understandings were mifled by paying an undue regard, partly to the obftacles overcome by weight; partly to matter as acted upon, or moved, by weight; partly to the pressure suffered by elaftic bodies; and finally to the velocities arifing from compound motion. He attacks LEIBNITZ moft feverely, while he enters upon a fundamental inquiry into the origin of his theory concerning the moving powers. It appears obvious to KANT, that LEIBNITZ had been led to this theory, by implicitly proceeding on the known rule from which DESCARTES explains the nature of the lever. Prior to LEIBNITZ, the world had admitted the fimple propofition of DESCARTES," that the mere velocity of bodies, even fuch as are in actual motion, ferves as a rule for afcertaining their power." But LEIBNITZ fuddenly roused the reasoning powers of man, by propofing a new law which, fince that period, has offered rich materials for difcuffion to the most learned and acute. DESCARTES had computed the powers of bodies in motion by mere velocity. But LEIBNITZ adopted the fquare of velocities in this computation. Whatever

Whatever merit may be due, from this CHRONOLOGICAL ANALYSIS, to the Recorder of KANT'S COLLECTIVE WORKS, and from baving engaged in a task-perhaps the most toilfome in life;-I have ftill to lament the impoffibility, or rather the impracticability of giving the refpective contents of each work at full length; efpecially when I confider, both the limited fize of thefe ELEMENTS, and the almost boundlefs region of KANT's fpeculations.

Nothing, therefore, but the well-founded hope, that no reasonable man will expect to find in these CONTENTS more, or less, than I have promifed, can fupport me in this laborious undertaking.

CONTENTS.

CHAPTER FIRST. Of the power of bodies, in general. § 1. Every mechanical body poffeffes an effential power. 2. This power of bodies LEIBNITZ expreffed by the common name, effective power. 3. It ought to be called vis motrix (moving power). 4. On the method of explaining motion from the effective powers in general. 5. Of the difficulties arifing from the theory of reciprocal operation of body and mind, if we attribute to the former no other power, than the vis motrix. 6. Of the obstacles thence arifing in the explanation of the manner, in which the mind affects the body; of the method of removing them, if we adopt a common vis activa. 7. There may exift things, the prefence of which cannot be at all demonftrated. 8. It is not improbable, in a ftrict metaphyfical fenfe, that there may be more than one world 9. If bodies, or fubftances, had no power to operate externally, there would be neither extenfion nor space. 10. The triple dimension of space is probably derived from the law, according to which the powers of substances affect each other. 11. Of the condition which renders the exiftence of a plurality of worlds probable. 12. Some Metaphysicians maintain, that bodies, by means of their (peculiar) powers, incline towards motion in all directions

13, 14. Two objec tions against this opinion: a.) That the moving body does not advance in an equal ratio with the body moved; b.) That the effort towards motion, which substances manifeft in all directions, must have a certain degree of intenfity; for it cannot be infinite, and a finite (limited) exertion, without a certain degree of effort, involves a contradiction. 15. Motion must be confidered to be of two different kinds. 16. Motion of the first kind is analogous to dead (inert) preffure. 17. 18. 19. Mo tion of the fecond kind prefuppofes a power, which corresponds with the square of velocity.

CHAPTER SECOND. Inquiry into the principles, upon which the adherents of LEIBNITZ explain the living powers. § 20, 21 BUELFINGER's advice in fettling differences between parties 22. LEIBNITZ's and DESCARTES's method of computing powers. 23. Firft error of LEIBNITZ, in afferting "if a body is in actual motion,

its power is equal to the square of its velocity." 24. Actual motion is that, which is not merely at the point of beginning, but during which a certain time has elapfed. This intermediate time, between the beginning of motion and the mo ment in which the body moves, properly constitutes what is called actual motion. 25. Second error of Leibnitz, " that the time confumed during motion is the true and only character of living power, and that from this alone the difference of computing dead and living powers must result." 26. Further proof against Leibnitz, from the law of continuity. 27. The time elapfed during motion, confequently the reality of motion, is not the true criterion of computing the living power of bodies. 28, 29. Mathematics cannot prove the reality of living powers. 30. Leibnitz was first misled in the computation of living powers, by Defcartes's explanation of the lever. 31. HERRMANN's affertion, that the powers are in proportion to the heights, to which they may rife. 32. Refutation of this affertion. 33. The followers of Descartes commit the fame error. 34, 35. LICHTSCHEID'S doubts upon this head removed. 36. 37. 38. An instance which proves, that in the computation of power arifing from weight, time must be neceffarily taken into account. 39. Summary of all the proofs derived from the motion of elaftic bodies. 40. The Leibnitzians refute their own conjectures, through the Systenis of Mechanics which they establish. 41. Herrmann's statement, refpecting the repulfion of three elastic bodies, examined. 42, 43. The origin of the fallacy in the reafoning, by which he established his conclufion. 44. This conclusion was unknown to Mad. de CHASTELET. 45, 46, 47. JURIN's objection concerning the reciprocal pulfion of two elastic and unequal bodies ;——BERNOUILLI'S answer to this objection, in comparing it with the preffure fuffered by elastic bodies;—his ideas on the fubject are refuted by his own premifes, which confirm KANT's opinion. 48. Defence of the living powers, fupported by the conftant balance of power in the world. 49, 50. Two different ways of explaining this affertion. 51. The fource of Leibnitz's hypothesis relative to the prefervation of a uniform power, with proposals for fettling this controversy, and a conclusive answer to bis affertion. 52. According to the law established by LEIBNITZ, the power exercised in the touch, hetween a small and a larger elastic body, is the fame before as after this contact. 53. The fallacy of this observation itself refutes the theory of the living powers, as maintained by the Leibnitzians. 54. This appears ftill more obvious, by inverting the case; if, namely, a larger claftic body is brought into contact with a smaller one. 55. Calculation affords proofs of the Cartefian law, that " if a larger body touches a smaller one, there remains an equal proportion of power." 56. The power, with which a smaller body recoils from a larger one, is called minus. 57. Mad. de CHASTELET has very improperly ridiculed this determination, which M. de MAIRAN firft proposed. 58. The Leibnitzians fhrink from the inquiry into the living powers, by means of the pulfion obferved in unelaftic bodies. 59. The latter is more decifive in determining the living powers, than the resistance of elastic bodies. 60, 61. The Leibnitzians give a frivolous answer to these objections, by saying, that " in the repulfion of unelastic bodies, one half of the power is confumed in the impreffion