Kant's thought is thus key to understanding that these philosophies, which appear on the surface to be widely different, are in fact quite similar.
In classical analytic philosophy, such as that of Aristotle, you have the a priori, (that which is before, and is given or assumed, which is an abstract general), and the a posteriori, that which comes after, the particular, the concrete, the data. Knowledge is obtained by confirming the former with the concrete data of the later. The concrete data might be a concrete perception, an image. The a priori its abstract meaning or name.
Kant's revolutionary idea was to give a method for obtaining knowledge of the a priori from the a posteriori, something never done before other than by empirical observation, and show their inverse dissimilarity. In this he provided a method to obtain the a priori from the mind itself, through its judgements. There are few achievements in western philosophy as enormous as this.
This can be referred to as the pragmatic approach to synthesis-- what the mind DOES- This turn to the mind of man as a necessary ingredient in metaphysics was crucial to Heidegger's -- and thus Rahner's -- enormous successes.
An important point I had overlooked with regard to free will, and the scholastics, from what you say, seem to have overlooked as well, was Paul's observation In Romans-- and it is also found in Augustine -- that man by himself can will only evil. And as Luther found from his reading of Romans, it is only through God's grace that man can will (and do) anything good.
The dualism of mind and space is sometimes referred to as the Double Aspect theory, which you can Google on. Kant probably spelled it out most precisely, but I can't give you a reference, other than the page cited below, I am also studying it.
Kant's Transcendental Deduction
In my view, the key to understanding what the mind is is to study Kant's transcendental deduction, which is the central section of his Critique of Pure Reason. It is a deduction of the properties of mind (what it is) from its behavior (what it does). The basic idea is that the mind is so constructed that we can make sense of objects. By examing the possible types of objects we can perceive, Kant arrives at a set of categories necessary to do the job. Necessary is the key word.
An interesting observation that emerges from such an approach is the behavioral description of the self or observer. It does not change in time. This says to me that it is beyond the realm of everday existence. The taoists speak of two realms of existence which emerge from, and later return to, the T'ai Chi or timeless universal spirit-energy: the timeless symmetical space-ordered world of Early Heaven of Fu Xi, and that of Later Heaven of King Wen, which is the everyday world of time and space.
These roughly correspond repsectively to Kant's a priori and a posteriori worlds. What Kant did was to place mind between these two worlds to deduce the categories of Fu Xi or the a priori (sounds like Early Heaven, doesn't it !) from the a posteriori (posteriori is like Later-> later heaven).
You could also use Peirce's categories for Kant's deduction if you flip the inside/out and the time order:
Thirdness == a priori or Law (possibly Sheldrake's morphisms)
Secondness == the mind or thinking, quantity
Firstness == a posteriori or quality
While the deduction can be notoriously difficult to understand because of the technical terms involved, and some have spent entire careers studying it, there are several accounts on the web, such as that found at
Peirce's categories align to it as well.
Kant's theory of space and time
Kant's theory of space and time shows that his concept of space,
"........that space and time do not really exist outside of us but are "forms of intuition," i.e. conditions of perception, imposed by our own minds"
is essentially that of inclusionality. The phase "do not really exist outside of us" is true, for the space we observe is not space itself, but what is IN space.
For more details, see below.
- Roger Clough
What space and time are:
Kant proposes that space and time do not really exist outside of us but are "forms of intuition," i.e. conditions of perception, imposed by our own minds. This enables him to reconcile Newton and Leibniz: agreeing with Newton that space is absolute and real for objects in experience, i.e. for phenomenal objects open to science, but agreeing with Leibniz that space is really nothing in terms of objects as they exist apart from us, i.e. with things in themselves.
How space is known:
Kant does not believe that the axioms of geometry are self-evident or true in any logically necessary way. They are logically "synthetic," which means that they may be denied without contradiction. That is a significant claim because it would mean that consistent non-Euclidean geometries are possible (which would involve the denial of one or more of the axioms of Euclid, as Bolyai, Lobachevskii and Riemann actually accomplished). Nevertheless, Kant did believe that the axioms of geometry are known "a priori," i.e. that they are known to be true prior to all experience, because Euclidean axioms depend on our "pure intuition" of space, namely space as we are able to imaginatively visualize it. Only if non-Euclidean space can be visualized would Kant be wrong.
The cosmology of space and time:
Kant does not think we can know, or even imagine, the universe as either finite or infinite, in space or in time, because space and time are only forms of perception and cannot be imagined or visualized as absolute wholes. The universe, as the place of things in themselves, is not in space or in time and so is neither finite nor infinite in space or in time. Thus there cannot be an a priori, rational or metaphysical, cosmology. Kant's Antinomies are intended to show that contradictory metaphysical absolutes can be argued and justified with equal force, meaning that neither can actually be proven. It can be argued however, that Einstein answered Kant by proposing a non-Euclidean (Riemannian) universe that is finite but unbounded (i.e. without an edge).
Joseph Marechal was the first to apply Kant's transcendental deduction
to Aquinas, by modifying Kant's treatment -- essentially extending his
set of categories-- in such a way that the Divine (presumably in the
form of the Holy Spirit) can act through the mind.
This is of great interest in understanding how we might relate with or
communicate with God, but it is also somewhat controversial.
Kant's transcendental deduction is the central section of his Critique of Pure Reason.
It is a deduction of the properties of mind (what it is) from its behavior (what it does).
The basic idea of Kant was that the mind is so constructed that we can make
sense of objects. By examing the possible types of objects we can perceive,
Kant arriveds at a set of categories necessary to do the job.
While the deduction can be notoriously difficult to understand
because of the technical terms involved, and some have spent
entire careers studying it, there are some fairly readable accounts on the web,
such as that found at
Although Marechal's description includes a more Thomistic type of anthropolgy,
to my mind at least, Marechal, in effect by allowing divine activity to act on or
interface with the mind, extended Kant's set of categories to include categories
such as Absolute, Infinite Being, God. That is where the controversy centers,
in the same space as the human categories of Kant.
The suggestion is that the divine activities belong to a higher realm of
potential categories, as I understand it.
Perhaps there is some help available with an analogy to Taoist thought,
a topic I am familiar with. An interesting observation that emerges from Kant's deduction is
the behavioral description of the self or observer. It does not change in time.
This says to me that it is beyond the realm of everday existence.
The taoists speak of two realms of existence which emerge from,
and later return to, the T'ai Chi or timeless universal spirit-energy:
the timeless symmetical space-ordered world of Early Heaven of Fu Xi, and that
of Later Heaven of King Wen, which is the everyday world of time and space.
These roughly correspond repsectively to Kant's a priori and a posteriori worlds.
What Kant did was to place mind between these two worlds to
deduce the categories of Fu Xi or the a priori (sounds like Early Heaven,
doesn't it !) from the a posteriori (posteriori is like Later-> later heaven).
The T'ai Chi would correspond to Rahner's and Tillich's ground of all being,
Early heaven to Kant's a priori and Later heaven to Kant's a posteriori.
In this way everything is grounded in God.
Rahner, the transcendental Heideggerian
After Catholic theologian Karl Rahner became a Jesuit, he was asked to obtain a doctorate in philosophy at Freiburg, Germany, where Martin Heidegger was rector. Rahner was greatly influenced by Heidegger's existential philosophy, but appalled at Heidegger's then-enthusiastic support of Nazism, so he studied under Honecker instead, although he attended Heidegger's seminars. One aspect of his doctoral thesis, Spirit in the World, concerned itself with an issue I am very interested in, what happens when we read the Bible.
When later asked what he had learned trhere from Heidgger, his standard reply was "He taught me how to think",
or a variant, "He taught me what happens when I read the Bible." In his thesis, Rahner had incorporated transcendence from Kant into the secular existentialism of Heidegger, a notable achievement. Here's more on this transcendence:
"Karl Rahner's approach to theology is characteristic of the 1930's: a Christian response to the secular loss of the transcendence of God. Whereas earlier generations met this challenge through liberalism and modernism, Rahner and his circle argued that the recovery of the sense of the transcendent could only be achieved through a reappropriation of the classical sources of Christian theology, especially Augustine and Aquinas. His approach fused German idealism and existentialism with Thomism.
Rahner believed that the polarity between "transcendence" and "immanence" was false, being imposed upon Christianity by secular world views. Human experience is unintelligible unless it is interpreted in light of the transcendent mystery of God through "transcendental reflection." Humans transcend themselves in every act of questioning and thinking, by which they demonstrate themselves to be both part of the natural world and yet simultaneously oriented towards the mysterious horizon of being that Christians know as God, the infinite horizon of hope and love. The dilemma of immanence or transcendence of God must thus be overcome without sacrificing either. Due to the ability of humans to discern the transcendent element of their situation, there is an implicit knowledge of God latent within humanity, which it is the function of transcendental reflection to identify. The sense of relation to God, a natural knowledge of God, he terms "transcendental revelation," but is inadequate in itself and needs to be supplemented by a supernatural knowledge of God, or "categorical revelation." This revelation reaches its climax and fulfillment in Jesus Christ."
Rahner's transcendental anthropology
"How does Rahner develop this philosophical theology? It is clear that in building his own system, Rahner always starts from the human as an existential unity, who is simultaneously historical and transcendental. On the one hand, the historical dimension of human being refers to the fact that we are always connected to the world through our spatio-temporal and actual (“categorical” in Rahner’s terms) experiences. In this sense, categorical experience is a posteriori experience. Even, Rahner maintains, our transcendental knowledge or experience of God, which is conditioned by our transcendentality, is also a posteriori, since it is “mediated by a categorical encounter with concrete reality in our world, both the world of things and the world of persons” (FCF, 52). "
To me, two modes of Rahner's anthropology look like the two halves of the brain given by Sperry's cerebral hemisphere
model of the brain- (for mind, really, not the brain)- with the right and left brain metaphors being:
left brain metaphor right brain metaphor
in time timeless
in the world transcendent/spiritual/inclusional
Rahner's transcendental psychology
Anton Losinger's "The Anthropological Turn - The Human Orientation of the
Theology of Karl Rahner" is a fairly slim volume minimizing the use of highly
technical terms, and so is a good concise introduction to Rahner's
"Foundations of Christain Faith", which even as a summary can be difficult
going. Yet even Losinger requires meditative slow reading.
On p. 24, an account of given of Rahner's tripartite psychology,
which is parallel to conventional tripartite psychology, even
to Peirce's categories, but including the transcents to/from God.
Peirce and conventional tripartite psychology can be described thusly:
Thirdness = doing & communication with others in the world
Secondness = thinking (communication with self)
First = sensing/feeling= raw perception
These seem to be roughly parallel or analogous to Rahner's transcendental
Communio = interactive communion in God's presence
God's communication to us through the Word (nature and grace)
Self-awareness (the possibility of transcendence)