There are two types of intuitions. The matter, which is the correspondence between the object of perception and the sensations, is known to us only through experience (a posteriori), and is relatively uncontroversial. The other type of intuition, the forms, is found in those intuitions which, as Kant asserts, must be present a priori to allow for an ordering of our sensations. To find these necessary forms one must bracket out all contingent sense data. When this is done those forms are found to be Space and Time. Forms do not exist in themselves (there are no noumena which relate directly to either), nor are they particular relations between appearances (merely contingent properties of an appearance), but Space and Time are instead the outer and inner senses, respectively.
To defend this position he offers metaphysical and transcendental expositions of the forms. His metaphysical exposition begins with Space and embarks on an analysis of what the idea must contain, namely that it is both a priori and an intuition. To justify his position our perception of Space must occur before all other experiences and before our understanding.
The first argument he offers asserts that “Space is not an empirical concept that has been drawn from outer experiences.” It is the case that our experiences are ordered in part by certain relations between ourselves and other objects, these objects are thought in Space. Without the representation of Space we would find ourselves incapable of any outer experiences. We do not come to know of Space through our experience, but rather it is through Space that our experience of objects which are distinct from our selves and from other objects is made possible. If this is so, then the form of Space must be a priori to all other particular intuitions. I have the sense of “out there” and can therefore distinguish between self and other/object, it is not logical to suppose that my experiences with distinct objects came before an immediate perception of ‘there.’
His second argument builds on the a priori nature of Space, asserting that it “is a necessary representation . . . that is the ground of all outer intuitions.” This is a stronger proposition that the first. Having shown that Space has an a priori nature, Kant now asserts that Space is necessarily a priori for our experience of the world. The representation of ‘not Space’ is not a possibility. While a person is capable of conceiving of emptiness or even a vacuum, she finds herself up against the limits of reason and unable to conceive no Space at all. It is Space which sets down the groundwork for our empirical experience of the external world. Just as above it was asserted that Space must precede any specific outer experience, in this section of the argument it is asserted that Space must precede all outer experiences. It is this outer sense, Space, which is the medium through which the external world is made sensible to us. According to Kant, the very fact that we have experience with appearances is proof of the necessary, a priori nature of Space. Our experience of the external world is conditioned by Space.
Kant now turns his attention to a proof of Space as an intuition. This is an essential movement as Kant must show to us that the forms of appearance are what compose the groundwork for our sensation; to do this the forms must occur in the sensibility as opposed to being in themselves concepts which mediate sensation via the understanding. For Space to be a necessary condition for the possibility of appearances, it must be found before the actual experience. He grounds this third argument in the differing natures of the intuitions and the concepts.
As the intuitions are in reference to particular objects, each intuition must refer to a particular, unified perception; the concepts, conversely, refer to a general group or classification and as such refer to a plurality. Intuitions, being the immediate experience of perception, act as atoms in building of concepts. Each intuition is singular and self-sufficient, being given to the passive sensibility, and only conditioned into concepts by the active faculty of our understanding. I do not have a singular experience or sensation which is ‘tulip.’ Instead my concept ‘tulip’ is made up of the individual sense perceptions which are given to my mind, through the forms. I receive a scent, a color, shapes, etc. and then sort these experiences into a general category which I label ‘tulip.’
Space is a unity and not a plurality. As Kant states, “one can only represent a single space.” Actual possible worlds and theoretically possible parallel universes aside, it is outside of the realm of human reason to think of a multiplicity of Space, just as one cannot conceive of no Space at all; the thoughts that we label ‘multiple spaces’ would be more accurately described as ‘parts of Space.’ Space is the platform upon which phenomena are represented to us; we do not have the choice of the second stage. While it enables concepts by making possible our perception of external objects, one cannot look within ‘Space’ to find its component parts.
Having thus shown what stems from our understanding of Space through the metaphysical exposition, Kant shifts his gaze to a transcendental exposition which will show that our actual experiences of the world follow from an a priori intuition, viz., Space. This argument is anchored to an idea that was contemporary with Kant which held mathematics and geometry to be synthetic rather than analytic judgments. He assumes that “geometry is a science that determines the properties of space synthetically and yet a priori.” This assumption in part stems from his third example within the metaphysical exposition. The axioms of geometry, for Kant, come to us ready-made. We need not, and indeed in some sense cannot, have a direct experience with a circle to be able to derive certain necessary properties pertaining to a circle. In applying the science of geometry to these axioms one is able to construct propositions and thus acquire synthetic knowledge a priori. As a concept is subject only to analysis, being merely an ordering tool (any additions to our knowledge of a concept would lead only to another concept), the Space with which we practice our science of geometry must itself be an intuition as we are capable of synthetic judgments within the science. As these axioms of geometry are necessary, as are all forms of mathematics, and the structure upon which we achieve these axioms of geometry is the intuition Space, it is the case that Space must be a priori. Were the basis of geometry to be a posteriori geometry would have to be contingent, as experience cannot offer certainty, but only probability.
Thus does Kant succinctly offer his justification for his proposal of the nature of Space.
It is important to note that for Kant’s project to succeed it is essential that Space and Time be a priori intuitions. By locating these ideas within the realm of appearances rather than as qualities of the transcendental noumena Kant offers a means for our limited reason to achieve knowledge of the external world which we collectively experience. By identifying Space and Time as the conditions for all possible experience rather than the concepts which organize experience he saves himself from a solipsistic reading of his transcendental idealism. If we are to have such a revolution of thought as he proposes, there is a real danger that we would find ourselves with purely subjective, and incommunicable, knowledge. If it is our minds that order our experience with things, how does objectivity obtain? With Space and Time acting as necessary conditions for appearances we all participate in the same empirical world. These outer and inner senses respectively set up how it is that we as human beings are able to conceive of the world. As Space and Time are only conditions for the representation of appearances, we are not committing ourselves to any specific knowledge of the unknowable things-in-themselves. It is possible that a being other than us experiences the world in a radically different manner, according to its specific subjective ordering. Space operates as our sense of ‘out there,’ where we can discriminate between experiences with distinct appearances just as Time acts as an inner sense, giving us the concept of causality. Thus are our experiences “transcendentally ideal,” that is particular to our human understanding of the appearances of things-in-themselves, and at the same time “empirically real,” or well founded and justified within our particular human reason.
Does Kant succeed in his project? This radical revolution of understanding appears at first blush to answer many of the empiricist’s concerns while avoiding the solipsistic pure idealism of the rationalist. However, should anyone of his founding assumptions be proven false Kant would be pressed to find an equally valid argument.
Works cited.
Guyer, Paul and Allen W. Wood, introduction to Critique of Pure Reason, by Immanuel
Kant, Guyer and Wood, trans. Cambridge: Cambridge University Press, 1998.
Kant, Immanuel. Critique of Pure Reason, Paul Guyer and Allen W. Wood, trans.
Cambridge: Cambridge University Press, 1998.
Paul Guyer and Allen W. Wood, introduction to Critique of Pure Reason, by Immanuel Kant, Guyer and Wood, trans (Cambridge: Cambridge University Press, 1998): 6
Immanuel Kant, Critique of Pure Reason Guyer and Wood, trans (Cambridge: Cambridge University Press, 1998): 110-1
There is debate around how strictly a priori must be read. For the purposes of this paper, I will be reading ‘a priori’ to be simply ‘prior to particular experience’, and not ‘without any previous experiences at all.’ This is, it seems, how Kant intended it to be read in this section.
