Edmund Husserl, answered from the texts and cited to the page.
The natural attitude — the natürliche Einstellung — is the name I give to the pervasive, pre-theoretical stance in which we ordinarily inhabit the world, the stance that must be understood before it can be suspended. In this attitude, the world is simply there. I find constantly on hand opposite me the one spatiotemporal actuality to which I myself belong, as do all other human beings; and I take it to be there, as it affords itself to me, as being there.1
Doubts, corrections, the occasional revision of this or that particular belief — none of these disturb the underlying thesis. Even when I strike something from the world under the title of illusion or hallucination, I do not thereby cancel the world; I merely correct what I took to be in it, while the world itself, in the sense of the general thesis, remains always there.2
The natural attitude is thus not a theory about the world; it is something more primitive and more tenacious — the operative positing of the world as the constant background of all my acts. Within this attitude, a further distinction matters. One can direct theoretical attention exclusively toward nature — making nature thematic and nothing else — and this is a naturalistic attitude, though it is important to see that making nature thematic is in a certain sense an abstracting, a willful exclusion of everything merely subjective, a conscious restriction of the field.3
But the natural attitude is broader than the naturalistic one; one can equally orient it toward persons and personal communities, toward the concrete surrounding worlds in which we live alongside and with one another — and in that orientation we and our life are, as subjects for the world, anonymous, as long as we have not made ourselves thematic for ourselves.4
Pure phenomenology, as I characterize it in the introduction to Ideas I — my 1913 systematic account of the method and its results — is an essentially new science that lies far afield of this natural thinking.5 Its first and by no means easy task is to achieve the phenomenological attitude and to reflect on its distinctiveness relative to the natural attitude, elevating that contrast into scientific consciousness.6
What that means in practice is the epoché, the radical alteration of the natural thesis: instead of remaining in the natural attitude, we want to alter it radically, suspending or bracketing the general positing rather than abolishing it.7 The difficulty, as I work it out in Ideas II — my analyses of constitution in nature, soul, and spirit, drafted across many years — is that we slip quite effortlessly from one attitude into another, from the naturalistic into the personalistic, and the involuntary changes pass unnoticed from want of pure reflection.8
Only within the framework of phenomenology, through the return to absolute consciousness and to the nexuses of essence to be pursued in it, is it possible to preserve these distinctions without confusion.9 So the natural attitude is neither a mistake nor a defect. It is the ground from which all inquiry begins, and the sciences of the natural attitude — the goal of which is to know the world more comprehensively and reliably than naive experience can — are entirely legitimate in their own domain.10
What phenomenology requires is not their abolition but the methodological step back that first makes visible what the natural attitude itself cannot see: the constituting intentional life through which any world is given as world at all.
I find constantly on hand opposite me the one spatiotemporal actuality to which I myself belong, as do all other human beings who find themselves in it and related to it in a similar way. I find the 'actuality' (the word already says as much) to be there in advance and I also take it affords itself to me, as being there.Ideas I, pp. 52–53
No doubt or rejection of anything given in the natural world changes anything in the natural attitude's general thesis. As an actuality, 'the' world is always there; at most it is here or there 'other' than I supposed; this or that is to be stricken from it, so to speak, under the title of 'illusion,' 'hallucination,' and the like.Ideas I, pp. 52–53
underlying a scientific attitude oriented toward nature is ultimately a willful making of nature into one's subject matter—in fact, pure nature, with the conscious exclusion, or will to exclude, everything that is merely subjective.The Crisis of European Sciences and Transcendental Phenomenology, p. 380
in the natural attitude it is we who are the persons carrying out the investigation; and thus, already in advance, it is we who live alongside one another and with one another. But here, as subjects for the world, we and our life are anonymous—as long as we have not made ourselves thematic for ourselves.The Crisis of European Sciences and Transcendental Phenomenology, p. 380
Pure phenomenology is an essentially new science, one that, by virtue of its very distinctiveness, lies far afield of natural thinking and consequently presses now, for the first time, for development.Ideas I, p. 3
achieving the phenomenological attitude, reflecting on its distinctiveness and that of the natural attitudes, as a means of elevating them into scientific consciousness—that is the first and by no means easy task.Ideas I, p. 3
Instead now of remaining in this attitude, we want to alter it radically. What is now required is to convince ourselves of the intrinsic possibility of this alteration.Ideas I, pp. 52–53
we constantly slip, quite effortlessly, from one attitude into another, from the naturalistic into the personalistic, and as to the respective sciences, from the natural sciences into the human sciences. The difficulties lie in the reflection and in the phenomenological understanding of the transformation of apprehension and experience.Ideas II, pp. 208–209
Only in the framework of phenomenology, through the relation of the ontological distinctions of the constituted objects to the correlative essential nexuses of the corresponding constituting manifolds, is it possible to preserve these distinctions without confusion, in absolutely certain distinctness, free from all misunderstandings which have their source in the involuntary changes in attitude.Ideas II, pp. 208–209
To know it more comprehensively, more reliably, and more perfectly in every respect than the naive experiential information can, to solve all the tasks of scientific knowledge that present themselves on its basis, that is the goal of the sciences in the natural attitude.Ideas I, pp. 52–53