Here can it and ought it to find and present to intuition its proper object- not only in itself, but in all its relations; or, if it employ conceptions, upon this ground it can always present the corresponding images in clear and unmistakable intuitions.It is quite unnecessary for it to renounce the guidance of nature, to attach itself to ideas, the objects of which it cannot know; because, as mere intellectual entities, they cannot be presented in any intuition.On the contrary, it is not even permitted to abandon its proper occupation, under the pretence that it has been brought to a conclusion (for it never can be), and to pass into the region of idealizing reason and transcendent conceptions, which it is not required to observe and explore the laws of nature, but merely to think and to imagine- secure from being contradicted by facts, because they have not been called as witnesses, but passed by, or perhaps subordinated to the so-called higher interests and considerations of pure reason.
Hence the empiricist will never allow himself to accept any epoch of nature for the first- the absolutely primal state; he will not believe that there can be limits to his outlook into her wide domains, nor pass from the objects of nature, which he can satisfactorily explain by means of observation and mathematical thought- which he can determine synthetically in intuition, to those which neither sense nor imagination can ever present in concreto; he will not concede the existence of a faculty in nature, operating independently of the laws of nature- a concession which would introduce uncertainty into the procedure of the understanding, which is guided by necessary laws to the observation of phenomena; nor, finally, will he permit himself to seek a cause beyond nature, inasmuch as we know nothing but it, and from it alone receive an objective basis for all our conceptions and instruction in the unvarying laws of things.
In truth, if the empirical philosopher had no other purpose in the establishment of his antithesis than to check the presumption of a reason which mistakes its true destination, which boasts of its insight and its knowledge, just where all insight and knowledge cease to exist, and regards that which is valid only in relation to a practical interest, as an advancement of the speculative interests of the mind (in order, when it is convenient for itself, to break the thread of our physical investigations, and, under pretence of extending our cognition, connect them with transcendental ideas, by means of which we really know only that we know nothing)- if, I say, the empiricist rested satisfied with this benefit, the principle advanced by him would be a maxim recommending moderation in the pretensions of reason and modesty in its affirmations, and at the same time would direct us to the right mode of extending the province of the understanding, by the help of the only true teacher, experience.
In obedience to this advice, intellectual hypotheses and faith would not be called in aid of our practical interests; nor should we introduce them under the pompous titles of science and insight.For speculative cognition cannot find an objective basis any other where than in experience; and, when we overstep its limits our synthesis, which requires ever new cognitions independent of experience, has no substratum of intuition upon which to build.
But if- as often happens- empiricism, in relation to ideas, becomes itself dogmatic and boldly denies that which is above the sphere of its phenomenal cognition, it falls itself into the error of intemperance- an error which is here all the more reprehensible, as thereby the practical interest of reason receives an irreparable injury.
And this constitutes the opposition between Epicureanism* and Platonism.
*It is, however, still a matter of doubt whether Epicurus ever propounded these principles as directions for the objective employment of the understanding.If, indeed, they were nothing more than maxims for the speculative exercise of reason, he gives evidence therein a more genuine philosophic spirit than any of the philosophers of antiquity.That, in the explanation of phenomena, we must proceed as if the field of inquiry had neither limits in space nor commencement in time; that we must be satisfied with the teaching of experience in reference to the material of which the world is posed; that we must not look for any other mode of the origination of events than that which is determined by the unalterable laws of nature; and finally, that we not employ the hypothesis of a cause distinct from the world to account for a phenomenon or for the world itself- are principles for the extension of speculative philosophy, and the discovery of the true sources of the principles of morals, which, however little conformed to in the present day, are undoubtedly correct.At the same time, any one desirous of ignoring, in mere speculation, these dogmatical propositions, need not for that reason be accused of denying them.
Both Epicurus and Plato assert more in their systems than they know.
The former encourages and advances science- although to the prejudice of the practical; the latter presents us with excellent principles for the investigation of the practical, but, in relation to everything regarding which we can attain to speculative cognition, permits reason to append idealistic explanations of natural phenomena, to the great injury of physical investigation.