LET US STOP FOR A MOMENT. Why does Hume’s Treatise (in comparison to which the Essay Concerning Human Understanding is badly watered down) represent such a great historical event? What happened there? The Cartesian radicalism of presuppositionlessness, with the goal of tracing genuine scientific knowledge back to the ultimate sources of validity and of grounding it absolutely upon them, required reflections directed toward the subject, required the regression to the knowing ego in his immanence. No matter how little one may have approved of Descartes’s epistemological procedure, one could no longer escape the necessity of this requirement. But was it possible to improve upon Descartes’s procedure? Was his goal, that of grounding absolutely the new philosophical rationalism, still attainable after the sceptical attacks? Speaking in favour of this from the start was the immense force of discoveries in mathematics and natural science that were proceeding at breakneck speed. And so all who themselves took part in these sciences through research or study were already certain that its truth, its method, bore the stamp of finality and exemplariness. And now empiricist scepticism brings to light what was already present in the Cartesian fundamental investigation but was not worked out, namely, that all knowledge of the world, the prescientific as well as the scientific, is an enormous enigma. It was easy to follow Descartes, when he went back to the apodictic ego, in interpreting the latter as soul, in taking the primal self-evidence to be the self-evidence of “inner perception.” And what was more plausible than the way in which Locke illustrated the reality of the detached soul and the history running its course within it, its internal genesis, by means of the “white paper” and thus naturalised this reality? But now, could the “idealism” of Berkeley and Hume, and finally scepticism with all its absurdity, be avoided? What a paradox! Nothing could cripple the peculiar force of the rapidly growing and, in their own accomplishments, unassailable exact sciences or the belief in their truth. And yet, as soon as one took into account that they are the accomplishments of the consciousness of knowing subjects, their self-evidence and clarity were transformed into incomprehensible absurdity. No offence was taken if, in Descartes, immanent sensibility engendered pictures of the world; but in Berkeley this sensibility engendered the world of bodies itself; and in Hume the entire soul, with its “impressions” and “ideas,” the forces belonging to it, conceived of by analogy to physical forces, its laws of association (as parallels to the law of gravity!), engendered the whole world, the world itself, not merely something like a picture – though, to be sure, this product was merely a fiction, a representation put together inwardly which was actually quite vague. And this is true of the world of the rational sciences as well as that of experientia vaga.
Was there not, here, in spite of the absurdity which may have been due to particular aspects of the presuppositions, a hidden and unavoidable truth to be felt? Was this not the revelation of a completely new way of assessing the objectivity of the world and its whole ontic meaning and, correlatively, that of the objective sciences, a way which did not attack their own validity but did attack their philosophical or metaphysical claim, that of absolute truth? Now at last it was possible and necessary to become aware of the fact – which had remained completely unconsidered in these sciences – that the life of consciousness is a life of accomplishment: the accomplishment, right or wrong, of ontic meaning, even sensibly intuited meaning, and all the more of scientific meaning. Descartes had not pondered the fact that, just as the sensible world, that of everyday life, is the cogitatum of sensing cogitationes, so the scientific world is the cogitatum of scientific cogitationes; and he had not noticed the circle in which he was involved when he presupposed, in his proof of the existence of God, the possibility of inferences transcending the ego, when this possibility, after all, was supposed to be established only through this proof. The thought was quite remote from him that the whole world could itself be a cogitatum arising out of the universal synthesis of the variously flowing cogitationes and that, on a higher level, the rational accomplishment of the scientific cogitationes, built upon the former ones, could be constitutive of the scientific world. But was this thought not suggested, now, by Berkeley and Hume – under the presupposition that the absurdity of their empiricism lay only in a belief that was supposedly obvious, through which immanent reason had been driven out in advance? Through Berkeley’s and Hume’s revival and radicalisation of the Cartesian fundamental problem, “dogmatic” objectivism was, from the point of view of our critical presentation, shaken to the foundations. This is true not only of the mathematising objectivism, so inspiring to people of the time, which actually ascribed to the world itself a mathematical-rational in-itself (which we copy, so to speak, better and better in our more or less perfect theories); it was also true of the general objectivism which had been dominant for millennia.
Edmund Husserl, The Crisis of European Sciences and Transcendental Phenomenology