# On the Vital Principle/Preface

Having, after careful study of this Treatise, been led to the conclusion that Aristotle's object, in its composition, was to put before the world his own opinions as well as those of former and contemporaneous writers upon the Vital Principle, I have been induced to undertake a translation of it, in order to give the general reader the theories, hypotheses, and opinions which prevailed, at that early period of natural and physiological knowledge, upon life and its manifestations. The Treatise, indeed, records all the prevailing opinions upon living beings and sentient properties, which lie scattered through Aristotle's other physiological writings; and it displays, perhaps more than any other of his works, the extent of his knowledge, and the perspicacity of his intellect. Should it, however, be questioned whether a work, composed at a time when the special sciences pertaining to its subject were yet in their infancy, can be now of any value, it might be answered that, irrespective of any positive result, an interest must ever be taken in the investigation, truthfully conducted, of nature's operations; and that this, brief ​as it is, comprises many of the dogmata, of an otherwise enlightened age, upon the more abstruse topics of natural philosophy and physiology.
It is scarcely necessary to observe, that several versions of this Treatise are extant, but as they have been written under an impression that its design is rather psychological than physiological, this misapprehension has tended to vitiate, or render unintelligible what otherwise, as literary productions, might have done justice to the original. Some of the translators, besides, seem to have been but imperfectly acquainted with physiology, and this want of preliminary knowledge has sometimes led to a misapprehension of the text, and sometimes to an inadequate appreciation of what could be only suggestive. Thus, the causes which have contributed to make the text abstruse, and even in places unintelligible, have concurred in making the translations obscure, and occasionally incomprehensible; for besides indications of imperfect anatomical knowledge, the arguments in the Treatise can be regarded but as suggestions, and be elucidated only by reference to the more matured science of modern times. It cannot derogate from what is due to Aristotle, to admit that physiology, in his age, was not only encumbered with the hypotheses of earlier schools, but also dwarfed and distorted by imperfect acquaintance with those systems and organs of the living body, which ​he perceived, intuitively, to be necessary to a full comprehension of his subject. But although the opinions and conjectures of this Treatise may, from the advanced state of anatomy and physiology, have but little intrinsic value, the method adopted by Aristotle may not be undeserving the attention of those who, with a wider range of special knowledge, are better prepared for the undertaking; unless, indeed, the Vital Principle is to be set down among those final causes, which, lying beyond the human comprehension, are to be admitted as ultimate facts. Although this may be the case, however, some interest must be taken in a Treatise which is, not only indicative of Aristotle's style and mode of argument, but pregnant also, by allusion, with collateral information.
This version has been made with the intention of rendering it, in so far as the analogies of language would allow, a faithful transcript of the opinions and manner of Aristotle; and notes are added for the elucidation of passages which by no periphrasis could be made intelligible to the general reader. It may be observed that the mind, (ὁ νοῦς), although nowhere defined, appears, in this Treatise, to represent the abstract immaterial principle usually attributed to the ψυχή; for it alone is excluded from all direct participation in corporeal functions or changes.
​Although the title given to this version embodies, as I believe, Aristotle's idea, yet it is not pretended that the writers cited by him always employed the term ψυχή in his sense; or even that he, himself, was always consistent in the use of it. Plato was certainly not engaged upon material agencies or properties in his Phædo, and in the Timæus, which partakes of a physiological character, and as such has been criticised in this Treatise, the animating motor principle is treated of rather as an abstraction than as the originating and natural cause of life, through all its manifestations. The term Vital Principle, however, has been retained throughout, even where it may seem to be less apposite, as well to avoid the misapprehension which might be occasioned by the substitution of another term, (that of soul I mean,) which might then to some appear to be its synonym, as on account of the extreme difficulty of determining the point where the metonymy might, without question, be adopted.
This Translation is from the Oxford edition, collated with that of Trendelenburg; and this allusion to that eminent scholar affords me the opportunity of acknowledging the assistance which has been derived from his comments upon passages, which require, for elucidation, all the light that can be thrown upon them by tradition and learning.