Quite apart from its truth or falsity the theory of sensation has played a momentous historic role. With the advent of this theory modern philosophy began, striking out on a strange new path, which in the main it has followed for three centuries. Shortly after its first appearance the sensation theory shed its identity as a theory and assumed the guise of a pretheoretical certainty. In this guise it found obscurity in the murky background of the theory of ideas and of its companion piece, monadism. With ideas and monadism thus in tow the theory of sensation became the sovereign predilection which supplied the framework and ground rules for philosophizing in the modern vein, from Descartes to Husserl, much as revelation supplied the framework and ground rules for philosophizing in the medieval vein. Doubtless the time will come when the historian of philosophy on looking back will find the “modern” prepossession with sensations no less strange than the medieval prepossession with revelation.

In playing this sovereign role the sensation theory committed modern philosophy to a program of speculative theorizing. This speculative program has one central theme: how on the basis of sensations to account for scientific knowledge and how to overcome the monadic dualism which the theory of sensation entails. In placing this theme beyond the reach of inquiry modern philosophy in effect abandoned inquiry and gave itself over to the free construction of hypothetical systems. From the ensuing display of speculative ingenuity arose the many “isms” which make up the distinctive fabric of modern philosophy: idealism, empiricism, parallelism, materialism, pragmatism, phenomenalism, behaviorism, and the like, all of them but variations on the one central theme.

In one respect the most interesting of these variations is that of transcendental phenomenology. For it introduced into the traditional framework an alien element, intentionality, the very absence of which had made possible the inception of the sensation theory. In construing the relation of sensations to outer things as that of inner effects to outer causes, not that of awareness to object, Descartes substituted a causal relation for the intentional relation. This substitution was bound to be threatened when Brentano and Husserl revived intentionality and strove to fit it into the modern framework. But the threat was no less great to intentionality. For the two are so incompatible that one must yield to the other. With Brentano and Husserl intentionality gave way and suffered accordingly. It is now time, I submit, that the sensation theory give way to intentionality.

This is to imply, of course, that the theory of sensation is quite untenable. It is also to suggest that modern philosophy from Descartes to Husserl has been a monumental fallacy. This is a harsh verdict and far too sweeping. No great movement of thought can be thus summarily indicted. Fortunately, modern philosophy had other bases than the sensation theory and other interests than those of epistemology. Obviously the movement as a whole cannot be brought under this indictment, only that segment which derives directly from the theory of sensation. This segment, however, is so central and so large that its removal is bound to entail a vast renovation of the whole edifice.

There are signs that such a renovation is in the making, that speculation is giving way to inquiry. There is a growing suspicion of sense data. “Idea” has fallen into disuse, as though debased by its inherent ambiguity. Even monadism, the most stubbornly ingrained of all, appears on occasion to be relaxing the grim hold which it has taken on the modern mind. Heartening as all this is, it is not enough. Repudiation must be explicit. The whole complex must be disowned and with it the language which it has spawned, the language of sensations, which has become in effect the lingua franca of modern philosophy. In this language and its rules of use the sensation theory is so deeply sedimented as to become a vast predilection, a set of fixed habits of expression and thought. Here lies the sinister power of the tradition. Here is where the unwary is most likely to be betrayed and to relapse into the Cartesian malady.

To cure this Cartesian malady, to purge us of the incubus of sensations, would seem to be one of the aims implicit in the turn which contemporary philosophy has taken. Curiously, this turn was foreshadowed by Husserl himself in the great work of his later years, Die Krisis der Europäischen Wissenschaften. Here at the close of his career Husserl returned to the Lebenswelt, this time however not with the design of neutralizing and reducing it, as in the Ideas, so that he might abandon it for the transcendental realm, but with the design of probing its inner depths, its many-layered structures or “sedimentations,” so that he might recover the primal insights which gave rise to modern natural science and philosophy. In this penetrating inquiry into the “genesis” of modern thought Husser! led phenomenology away from speculation into the path of investigation.*

Heidegger, if I understand him at all, is relentlessly pursuing this course. He has completely abandoned transcendental phenomenology for genetic phenomenology. But the source which he is seeking lies even deeper than that of modern science and philosophy; it is the primordial insights or revelations that underlie the whole life of man, the life of mind passionately striving, in its encounter with “beings” to detect and express the deeper reverberations of “Being” itself.

From Husserl existentialism, too, has absorbed a profound concern for the Lebenswelt and is desperately at pains to lay bare its hidden sense and structure. To this end Sartre retains the reduction and so far reverts to transcendental phenomenology. But his reversion is also an alteration. For what the reduction discloses to Sartre is not a sublime transcendental ego but a terrible freedom of consciousness not only to disengage itself from a world it has constituted but, more imperatively, to recover this engagement, now recognized as an awesome task. In this highly ethical and activist context constitution is but a moment in an agonizing exercise of freedom, an inescapable mandate to transform self and society, even though by the conditions of that effort one is condemned to fail. As existence is prior to essence, so ethics is prior to ontology. And frustration is the crown of authentic existence—or so it would seem.

Merleau-Ponty, too, reverts to the reduction. But what the reduction reveals to him is not a transcendental consciousness, pure or empty; it is rather a consciousness so wedded to the world that it cannot even in idea disengage itself therefrom. The effort to disengage (the reduction) brings to awareness with finality the inextricable involvement of consciousness with the world, an involvement which is one with the existence of consciousness. Thus the reduction reveals the transcendence of the world, rather than that of consciousness. The inalienable presåïñå of the world is manifest in perception, through which we find ourselves in the Lebenswelt with its characteristic confusion and profusion, neither wholly senseless nor wholly sensible, rather “ambiguous.” To live in this ambiguity, to labor at its unending resolution, is to live in the secular world of history, as perforce we must. Philosophy is but a more acute awareness of this existential involvement.

From quite another side, a side where empirical rather than metaphysical motives tend to prevail, the Lebenswelt has moved covertly to the fore. I refer to linguistic analysis, which has found in language the key to philosophic understanding. The great promise of this movement lies in its growing tendency to see in language not only a “game” with its “rules of use,” but also and more importantly a luminous access to rerum natura, a great refracting medium, so to speak, through which man and nature come philosophically into view, as Plato pointed out long ago. The “language game” would then be seen to be virtually one with the great game of life itself. For language is in sooth the most distinctive creation of the natural attitude and its proper vehicle. Language is the Lebenswelt rendered articulate. As such it is a genuine prius, a genuine pretheoretical basis for philosophical inquiry. Also, the very use of language would seem to commit us to the “realism” of the Lebenswelt with a finality which precludes any “suspension” with its illusory “transposition of standpoints.”

Thus, from many sides contemporary philosophy seems to be converging on the Lebenswelt as though impelled by a common aim to return to the living center of human existence and value. Here, if anywhere, is the source of that understanding which will permit philosophy once again to enter into the mainstream of our feverish existence and to address itself to “the real business and fortunes of the human race.” If the mood of this aim is militantly secular, its secularism is not doctrinaire, not that of a preemptive formula religious or philosophical. Hence it is not inherently opposed to a possible life beyond the grave nor to a possible transcendence with which we must ultimately reckon. It is opposed, however, to allowing our preoccupation with these possibilities to interfere with the pressing business at hand: the “relief of man’s estate” through a conquest of nature in which all may share. Life this side of the grave can no longer be deferred.

If this be genuinely the aim which more or less unconsciously is drawing philosophy back to the Lebenswelt after three ñåïturies of wandering in the wasteland of sensations, it is none other than the grand motive which originally gave birth to the world we call “modern,” the motive of scientific humanism. In contemporary philosophy this motive would seem to be reasserting itself, calling for a return to sober inquiry after the long orgy of speculative theorizing initiated by Descartes. The brew which sustained this orgy was concocted of sensations, ideas, and monadism. If we are to eschew this brew, we must purge its noxious ingredients.

Just such a purge seems to be in the making: not as a project in its own right, but as the concomitant of a new spirit of inquiry impelled by a new sense of urgency. In this ferment we appear to be returning to the wellsprings of western thought. From this fresh stirring of the waters a truly classical revival may emerge—if, indeed, it is not already upon us.

* It is a pleasure at long last to say something favorable of Husserl. From my negative criticisms one might infer that I owe him nothing. Quite the contrary. My debt to Husserl is immense, as is evident on every page of this essay. If I have felt free to criticize unsparingly his transcendental phenomenology, it is chiefly because the genetic phenomenology of the Krisis has showed me another and better way.