We are asking the question: How is experience itself possible?
We have experiences, and all empirical knowledge emerges from experience. So, empiricists believe that all knowledge (in toto) emerges from experience.
But what is the nature of experience itself? What makes experience possible?
To answer that question, we must first contrast the greatest empiricist, David Hume, with the transcendental idealist, Immanuel Kant. Please read the pages linked to from their names, and then return here to continue.
For Hume, experience is possible because we are awash in sensory impressions that the world gives us. Our ideas, then, emerge from the world and are thereby about the world. Depending upon how we think with such ideas, we are either just manipulating concepts (“relations of ideas”), or we are actually contemplating the world (“matters of fact”). Experience, then, is the passive receiver getting real-world data directly from the world and thereby having ideas about the world based upon the experiences the receiver has from the world.
This is a very common-sense view, and it is the very basis of science!
By contrast, Kant argues that not all of our “about the world” ideas emerge “from” the world. Thus, not all of the features of our experiences are “from the world,” even though they are indeed “about the world.” Some fundamental features of all of experience come “from us,” and the world itself conforms to those features of our experiences.
Imagine that you were born with rose-colored lenses implanted into your eyes. You never realize that you are seeing the world through rose-colored lenses. In fact, you cannot even imagine a world not rose-colored. The world for you just is rosy, and you have no clue that you are contributing this rosiness to all of your experiences. The rosiness is not “in the world.” The rosiness is “in you,” because you necessarily “filter” all of the world through this rosiness. You can never get in touch with the world as non-rosy, and you never even imagine to try to think about the world that way.
You think, instead, that the world itself, as it is in itself, is rosy because you see a universality to this rosiness. All of your “about the world” experiences are rosy. So the world itself must be rosy. Thus, you derive from your experiences what the world is “really” like. But your metaphysics is necessarily tainted by rosiness.
However, if you could somehow discover that you are contributing rosiness to “the world,” you would then be able to distinguish between “the world” of appearances (necessary as that world is for you) and the world of “things in themselves.” And you would then realize that you could never do metaphysics regarding things in themselves because you can never remove the rose-colored lenses nor imagine a non-rosy world! You would then realize that metaphysics must be about the world of appearances, but coupled with an awareness that “there is something that appears” about which you can say very little more!
Kant proved that space and time are like the rose-colored lenses for us. Moreover, Kant proved that some core metaphysical concepts, such as causality, substance, continuity, and coexistence (among others) are “in us” and are aspects that we contribute to all of our experiences. Thus, all of our experiences are in a world of causality among substances because those concepts are among the rose-colored lenses we necessarily wear and “see” the world through.
All metaphysicians (except for, perhaps, the deeply confused Hegel) have recognized the distinction that Kant called appearances vs. things in themselves. But none prior to Kant proved that all of metaphysics is necessarily limited to the realm of appearances, that metaphysics can never penetrate to saying anything about things in themselves. (Hegel misunderstood Kant and spent his philosophy trying to deny this very conclusion.) So, both metaphysics and science can only speak to appearances, never to how things “really are” in themselves as “unconditioned” by us.
Moreover, Kant proved that the very process of having an experience necessarily depends upon a process of “synthesis” that is prior to all experience, and that this synthesis is based upon rules that inhere in something that is beyond all possible experience; therefore there is something that does the synthesis logically prior to existence and experience.
This something, this “I think,” as Kant calls it, is not the “I” that we each experience when we look inward. That empirical “I” that we experience when we look inward is itself an experience! And even that experience is already “conditioned” by time (which we each contribute) and by the “categories” of possible experience that the “I think” contributes. Even our experience of ourselves is already processed, “synthesized,” and “categorized” by an “I think” that is forever beyond our awareness; about this “I” we can have no experience because all experience (even of ourselves) presumes its prior activities.
So, Kant argues that empiricism can never tell us about what we “really” are in ourselves, because empiricism must wait for experiences from which to have ideas about objects (including ourselves as objects). Yet, our experiences themselves necessarily depend upon the processing of the “I think,” so our knowledge of those processes cannot be empirical knowledge! Thus, whatever is this “I think,” it is forever beyond empirical perception. There can be no experience or awareness of it. Yet it must exist in order for us to have any experiences at all. Thus, Kant goes “below” empiricism to prove that empiricism rests upon the principles of transcendental idealism. He goes below “mind” that can be experienced and analyzed empirically to prove that mind must be something deeper and prior to the “mind” that we can experience.
For our purposes, then, whatever “mind” really is, we cannot know it empirically because it necessarily underlies all of our experiences, including our experiences of our own selves looking inward.
At this point, we’ve laid out some key terminology and where we are going with it.
Moving forward, we will outline Kant’s arguments that sustain these conclusions we’ve summarized.