[Descartes' model of perception; Image from the University of Bern Magazine]
[Based on the lectures of Greg Schufreider]
At the dawn of modernity (which launches it), Descartes asks, “What can I know for certain?” Doubting everything, he concludes, “Cogito, sum”: “I think, I am.” I don’t care how much I’m deceived; I must exist before I am deceived. There is no therefore: intuition (of a clear and distinct idea) is instant and immediate; no inference is needed—and that is precisely what distinguishes my certainty of myself from my certainty of other things. From the very moment that I think: I exist. That I know (and not just believe) for certain. Of myself, I have indubitable knowledge.
There are things around me that, unlike myself, I cannot change, things I have no control of. The external world, then, must exist, independent of consciousness. They exist indubitably, however, I can only be fully certain of them—in fact of anything, except myself—as long as I do not assume external correspondence, i.e. as long as I do not think that they correspond to anything outside my mind. I can be fully certain of my knowledge of things, but only as I am thinking them. I can be certain of all thoughts that I have, as long as I assume that they’re just that: thoughts. Yes, external things must exist, but the only way I can be indubitable about my knowledge of them is if I think of them only as things I am thinking of: as thoughts. Just by inspecting an idea, I can prove that it exists—but only as that, an idea, not (even though it exists) as a thing.
But they’re not just ideas, argues Husserl. Those things, after all, do appear to consciousness. Thus, we can be certain of those things (and not just of ideas of those things). We can be certain of those things, we can have indubitable knowledge of them—but if we analyze them only as they appear in consciousness, i.e. as phenomena. Unlike Kant, who had earlier defined phenomena as the appearance of something that does not appear (the noumena) (thus understanding is no longer a posteriori, but refers to the a priori categories of the mind; a priori because we never get to the noumena, but not straightforward rationalism/un-empiricism either because it is still the noumena that causes the phenomena to appear), Husserl’s phenomena is actually the appearance of something that appears. In Kant, we never get to the noumena (Kant missed time, the pregnant present affected by both the retention of what is past and the anticipation of what is future (such as in the formation of a unified perception as you take one-sided perspectives of an object and then combine them into a consistent whole); thus Kant thought of a priori structures as structures of the mind, when he should have seen them as structures of the experience itself, perceived through time.). In Husserl, the thing’s right there—but we’re sure of it only as it appears to us, i.e. as a phenomenon.
Thus we can be certain of things, but only as they appear to consciousness. We can make claims about them, but not about their independent existence, not about our metaphysical conceptions about them. We bracket off all those considerations and focus solely on how the experience appears to consciousness. We employ, in other words, the phenomenological reduction. We thus don’t think of thought as a mental event, as though there are external things out there causing thoughts in the mind. We do this not because what we get from our (empirical) perception of external things is false, but because it is dubitable. Instead, we think of the Cogito, consciousness, and the cogitata, the object of consciousness, which, the intending consciousness, in its intending, always has, and which, in its self-givenness, is intuited, given to the intending consciousness as an experience, as a phenomenon that is presented to consciousness. We are thus no longer merely indubitable about ideas: we have certain knowledge of things—but as phenomena, as they appear to consciousness. From what we can be fully certain, from foundations that are indubitable, we are then able to erect our notion of truth.