The world of philosophy that German Idealism is responding and reacting against is the world of the so-called new science, Enlightenment philosophy, which can roughly be said to have begun with the publication of Sir Francis Bacon’s Novum Organum, the New Science, in 1620. Tied to the new science is Rene Descartes and his Meditations on First Philosophy; the two are brought together in the pursuit of the modern project: The conquest of nature (begun by Bacon) and the attempt to understand the self (begun by Descartes even though the quest for self-knowledge really began with the existential phenomenology of Saint Augustine).
Bacon was an English philosopher, scientist, and statesman who helped to establish the tradition of philosophy now known as empiricism; his was a philosophy of reductionist materialism that reduced the world to an instrumented object—this including subject beings. Humans were nothing more than a material mass of atoms composed together in motion as everything else in the object-world was. However, man had the unique ability to dominate; and, according to Bacon, to advance our knowledge man had interrogate nature on the rack of investigation. Empirical science is the outcome of the instrumental exploitation of nature; this also brings about the end of the science of vitalism, the “pre-modern” scientific worldview begun by the Greeks and inherited by Christianity through Neoplatonism which argued that the world and all lifeforms therein had distinct and particular life forces, and intelligibility in them. Vitalism can be summed up as the outlook that “living organisms are fundamentally different from non-living entities because they contain some non-physical element or are governed by different principles than are inanimate things.” In essence, Baconian science stripped man of his vitalism—his life essence—and turned into a material object of the world; ultimately no different than other objects in the world.
We are familiar with this outlook today—popular scientistic intellectuals and philosophers like Sam Harris, Richard Dawkins, and Daniel Dennett exhibit these views. Critics of this view call this reductionist materialist worldview the “nothing-but” outlook; humans are nothing but atoms composed and hitting each other in a certain manner which give the appearance of a human; trees are nothing but atoms composed and hitting each other in a certain manner which give the appearance of a tree; a dog is nothing but atoms composed and hitting each other in a certain manner which give the appearance of a dog; and so on. Man is reduced to an object in a world of objects for all objects follow mechanical and mathematical laws.
Although Bacon was, properly, a monistic materialistic, his sidestepping (or eradication) of consciousness produced a functional dualism: a dualism that pitted man against nature as the supreme object of force. Man could not dwell in nature. Man would simply overwhelm and destroy nature; the forces of science and industry would be unleashed by man’s motionary movement.
On the opposite end of Bacon was the French rationalist Rene Descartes. Descartes is probably best remembered to posterity as the philosopher who proved human existence by saying “I think, therefore I am” (the cogito ergo sum). The task of Descartes’ philosophy, Cartesian philosophy, was to affirm the subject’s own subjectivity; to affirm one’s own existence.
The problem that arises from Descartes’ philosophy is the classical mind-body problem. Are humans a mind inhabiting a body, or a body with a mind. What is the mind? Unwittingly, Descartes “dualism” (so-called) ended up advancing the Baconian outlook. Man was a body, and his mind was nothing but matter. But this wasn’t so much the problem with Descartes that the German idealists took. Later generations of Cartesian rationalists ended up becoming subjective solipsists; that is, I could only affirm my own existence. In a world where only the I-Think could prove its own existence, I am forever cut-off from others; the others that I perceive to be existing may or may not be existing, I can never know because I do not have access to their minds. I can never think as another beside myself, therefore, I can never affirm anyone’s own existence besides my own. The result is a detachment and flight from the material world and the world of others. Admittedly, this is not what Descartes intended but the tradition of philosophy spawned by his thought nevertheless exhausted itself into a solipsistic rationalism where the self was forever awash in a sea of isolated and atomized minds and particles.
It is this world of philosophy that German Idealism, coming into form with Immanuel Kant, is reacting against. The task of Kantian idealism, or simply the task that Kant dwelled upon for nearly a decade and finally published The Critique of Pure Reason in response to, was how to achieve the apperceptive unity of the I and Not-I, the I-Think with other I-Thinks and with the phenomenal world of space and time without allowing subjects to becoming objectified and instrumentalized into conformity with the determinacy of mathematical laws (which would reduce subject-beings into objects) and keeping subjects detached from each other. The I-Think, the thinking subject, must be able to accompany all representations it encounters and perceives, and this is what self-consciousness is.
Kant, then, revises the Cartesian and Baconian outlook by starting with the mind, like Descartes, but attaching the phenomenal world to the mind. Mind comes into existence with innates ideas. In this way Kant is following Plato and can be said to be a revisionist Platonist. The Categories of the mind are also lifted from Aristotle. While the mind comes into existence with innate ideas—thus denying the tabula rasa (blank slate) of John Locke (an outlook now also generally rejected by all except the most fervent defenders of the reductionist model of science)—space and time, the phenomenal realm of experience and sensation, are forms of a priori intuitions that the mind projects. That is, mind, not body, is the seat of sensation and experience.
It is wrong to deduce, as the reductionists do, that our bodily experiences and sensations are only tied to the body; Kant argues that they are really tied back to the mind as sensational experiences are rooted in consciousness, in thought, in the mind’s innate ideas, and so on. What we experience comes through mental faculties; and mental faculties are not reducible to a bland hunk of meat and atoms as the reductionist materialists claim. Plants, for instance, are material bodies with atoms but plants do not have sensory experiences because they do not have consciousness. Animals, which have material bodies and are also atoms, do feel because they have minds but they are not self-conscious; that is, they are not “rational” in the classical sense. Reason, for Kant, is that which permits man to know his nature, to know and experience the transcendentals: The Good, the True, and the Beautiful. Animals, as far as we know—back in Kant’s time and today—do not have this in-dwelling of reason which prevents them from having a unitive relationship with the transcendentals and a coming to understand nature though they do, unlike what Descartes argued, have the ability for basic sensory experiences precisely because they have raw animal minds.
The mind, according to Kant, cannot exist without this ability to project the phenomenal realm of objects which are, as stated, a projection of the mind.
This brings us to the synthetic a priori in Kantian philosophy. As the mind comes into being with innate ideas, this means that our innate ideas, from Kant’s perspective, can be confirmed in the world of phenomenon. The a priori is that which is known without experience. The a priori is that which is true by definition; like all bachelors are unmarried. One does not need to meet a bachelor to confirm this reality. It is an a priori (logical) truth. A posteriori is that which is known, or confirmed, by experience. One needs to have a direct experience to validate an a posteriori claim to knowledge. For example, John was planting a flower in the afternoon. This can only be known from experience; that I saw or encountered John planting a flower in the afternoon. If I do not have this direct experience, I cannot make a valid epistemological claim.
Kant’s synthetic a priori bridges the a priori and a posteriori together. Again, because the phenomenal realm (the world of a posteriori) is a projection of the mind (the world of a priori) which permits us to confirm a priori ideas. The synthetic a priori, then, is where the world of phenomenon is linked to the world of thought. The synthetic a priori is where thought and experience meet. And where they meet the apperceptive unity that was lost in the world of Bacon (by, ultimately, denying thought by objectifying everything) and Descartes (by only being able to confirm the a priori detached, entirely, from the phenomenal world). Moreover, the synthetic and a priori coming together also enriches knowledge because our experiences which confirm a priori knowledge ensures a priori knowledge isn’t dry intellectual thought; it has real-world reality and consequences.
But Kant’s philosophical project begins with mind. It does not begin with the phenomenal world of objects or nature. Instead, the phenomenal world is a projection of our mind, our thought, our consciousness. If I exist without thought, I am an object. But I would have no knowledge of my existence. A rock, for instance, has no knowledge of its existence. A rock exists because it exists as a projection of the human mind and its sensory experiences. Ergo, for Kant, existence and knowledge of existence is tied back to mind, which is tied to the self.
Besides being concerned with metaphysical-epistemological concerns, Kant was deeply interested in the question of identity and how identity was related to the larger metaphysical-epistemic crisis wrought by modern philosophy. Looking upon the empiricists, man was an empty body—the “hollow man” as T.S. Eliot would later go on to explain. Looking upon the rationalists, especially Descartes, the cogito ergo sum proved thinking but not that I was actually the one doing the thinking. For Kant, the question of identity was necessary for thinking: The I-Think.
The notion of the Transcendental Self, the I-Think, in Kant’s ontological philosophy is the grounding of the self with thought through the apperceptive unity of the synthetic a priori. Since my mind is the seat of sensation and I think and perceive, the self is behind perception and not an object of perception. Moreover, for Kant, the self is what we do. Selfhood is the activity of consciousness, action and engagement, with the phenomenal world of space and time. In this way Kant bequeaths to German philosophy the notion of being as action, a being in the process of doing or becoming and something that isn’t fixed in the classical sense. The only thing fixed about the being of man is that he is rational, i.e. to organize ideas and experiences.
Kant’s understanding of the self is twofold. There is the empirical ego and the transcendental ego. The transcendental ego is the true self; the self-in-itself, how we identify ourselves and understand ourselves. The empirical ego is how others identify us. In other words, the empirical ego is the self that others encounter and perceive from their minds but they do not have access to our transcendental, interior, self.
If the phenomenal world is a projection of the mind, and there exists other persons, other selves who are not me, this is the origin of the I/Not-I distinction in Kantian philosophy that will be picked up upon principally by Fichte and Hegel. The I is the total self: empirical and transcendental, though the true self is always the transcendental self. Only I can be the total self because I control how I appear to others and I know myself.
Sticking with how this relates to the synthetic a priori and the noumenon, the transcendental ego projecting into the realm of space and time therefore perceives others (the empirical ego). However, the noumenal not-I is the transcendental ego/“true self” that I do not have access to. Therefore, I can only ever know another person in the empirical sense. Kant’s philosophy of selfhood is intimately tied with, and the outgrowth of, his philosophy of the synthetic a priori and noumenon.
Thus, in Kant, as the famous saying goes, he had to limit knowledge to ensure knowledge. However, this was deeply unsatisfying to the post-Kantians, the first of whom was Johann Fichte who built from the spirit of Kantian philosophy but wanted total knowledge because the limited knowledge of Kant was insufficient in warding off the skeptics.