Heidegger on Western philosophy
Ontotheology means the science of God and Being. It is about God-as-Being as much as Being-as-God.
God-Being is strange to think about. We usually emphasize one part or find them at odds with each other.
In his Two Treatises of Government, Locke argues in two different ways for the justification and limits of government, one religious and one secular, but paradoxically God features in both. Descartes wanted to give philosophy an absolute grounding that no skepticism could destroy in his Meditations. Descartes incorporated the skeptic as part of his own philosophy, reaching the absolute ground of the cogito ergo sum. When it comes to moving from the small but guaranteed ground of the cogito, Descartes brought God back into the fold.
Philosophy departments view Locke and Descartes as important for the canon and development of philosophy, but only teach their ontology. For Locke and Descartes, professors view the incorporation of God with philosophy as a regression, artificial, or dogmatic.
This narrative of progress and regression of secularism is especially true for Kant. The first Critique was revolutionary in breaking away from ontotheology. Kant's critique of the dogmatism of his predecessors aligns with our modern sensibility that concepts like God, the soul, and freedom do not belong in our more refined and scientific world. The second Critique disappointed readers, where these same concepts became necessary postulates of practical reason.
Following Kant, Hegel disappointed the reader more. One does not need to go far to see the distaste with Hegel for this, look to the entire British philosophical reactions, notably Russel and Moore, to the Hegelian influenced British idealists such as Green, Bradley, and McTaggart.
"Accordingly, logic is to be understood as the system of pure reason, as the realm of pure thought." — (Hegel, Science of Logic, 21.34)
The modern reader projects their own distinctions onto these philosophers, thus obscuring the text even further. Ontotheology is not something philosophers consciously thought of themselves as doing. This compound term was made up by Heidegger to articulate the original unity of thinking in Western philosophy.
The first time he used this word was lecturing on Hegel's Phenomenology of Spirit in 1930-31. Heidegger returned to this phrase in a 1957 postscript to another seminar on Hegel, titled "The Onto-theo-logical Constitution of Metaphysics". It appeared in English as part of a larger collection of writing on Hegel called Identity and Difference, which was a major influence on Robert Pippin's The Culmination.
"Why is 'science'...why is science theology? Answer: because science is the systematic development of knowledge, the Being of beings knows itself as this knowledge, and thus it is in truth." — (Heidegger, Identity and Difference, p. 54)
For Heidegger, we have forgotten what it means to think Being as Being. Being has manifested in Western metaphysics in various forms since Plato through Hegel, but all equate Being as the illuminated "idea".
"All metaphysics, including its opponent, positivism, speaks the language of Plato. The basic word of its thinking...is eidos, idea." — (Heidegger, Basic Writings, p. 444)
The positivism of the Neo-Kantians or British analytic philosophers of Heidegger's day, or even for the theologians of 400CE such as Saint Augustine, all treat Being as idea, intelligibility, presence, the light.
"For I did not know that the soul needs to be enlightened by light from outside itself...You will light my lamp, O Lord." — (Saint Augustine, Confessions, p. 68)
Theology emphasizes the Being-as-God aspect of ontotheology, but it is ontotheological nonetheless. Platonic philosophy, particularly Plotinus's neo-Platonism, heavily influenced Augustine. Plotinus, after the Bible, is probably the most referenced person in Augustine's Confessions, Cicero not far behind.
Philosophers have different terms for what plays the role of the "light" in their philosophy. Heidegger names many: Idea, will to power, will to will, monad, God, logos, hypokeímenon, substance, subject, self-consciousness. In all of these ontotheologies, Being is associated as the ground of beings. Only in the light of God are beings intelligible, only in the will to power are beings intelligible.
Each presencing of Being in the history of philosophy further obscures Being as Being. When there are so many competing philosophies that lay claim to the truth of Being, the task of philosopher is more of a destroyer than a builder. Just like Rashomon by Akira Kurosawa, the philosopher has to not only discern the truth, but has to peel away and untangle the layers built on top of Being.
Heidegger claims that all this presence and illumination not only obscures Being as Being, but is only made possible through a primordial relation to Being.
"But what remains unthought in the matter of philosophy as well as in its method? Speculative dialectic is a mode in which the matter of philosophy comes to appear of itself and for itself, and thus becomes present." — (Heidegger, Basic Writings, p. 441)
We call this openness that grants a possible letting appear and show "clearing". In the history of language the German word Lichtung is experienced in contrast to dense forest, called Dickung in our older language. The substantive Lichtung goes back to the verb lichten. The adjective licht is the same word as "light". To lighten something means to make it light, free and open, e.g., to make the forest free of trees at one place.
In addition to the philosopher as illuminator, there is the counter-philosopher, the skeptic. The skeptic is the darkness. These are well known in the history of philosophy, that there is nothing constant and there is only flux. There is no knowledge. There is no world or mind. There are no values. Language cannot communicate. There is no meaning. There is no logical argument for grounding logic.
But the darkness is also not what Heidegger is talking about. Heidegger is not a skeptic of truth as we know it from Plato or Hegel, or even the positivists idea of truth. Heidegger is after something more fundamental.
The early Heidegger of Being and Time was still too close to the type of philosophy he associates with presencing and illumination, that of Kant or Hegel. Heidegger agrees with the Kantian critique of dogmatism and transcendental realism. For things to be intelligible, there must be something about man that makes intelligibility possible, hence transcendental idealism. Heidegger's Dasein, the being who's being is a problem for itself, is greatly influenced by Kant. The influence is shown in his Kant and the Problem of Metaphysics and the Phenomenological Interpretation of Kant's Critique of Pure Reason.
The error in ontotheology that culminates in the philosophy of Hegel is that it is too subjective. Heidegger, in his "Letter on Humanism" essay, attempts to distance his idea of Dasein from the more subjectivist Being and Time.
"...man occurs essentially in such a way that he is the 'there' [das 'Da'], that is, the clearing of being." — Letter on Humanism
However, Dasein falls out of his vocabulary as we enter the later Heidegger's writing. Instead, there is the "clearing" and aletheia. It follows that if Western philosophy had forgotten Being, one should go to the beginnings. Heidegger's search for the truth of Being finds home in the pre-Socratic philosophers, especially Parmenides and Heraclitus who Heidegger view as closer to Being.
"We must think aletheia, unconcealment, as the clearing that first grants Being and thinking, and their presencing to and for each other." — (Heidegger, Basic Writings, p. 445-7)
Aletheia comes closer to Heidegger's long search for Being. Just as illumination and darkness depends on the clearing, certainty and uncertainty depend on unconcealment. Western philosophy thinks of truth as the certainty of judging and making intelligible that judging of beings. This is the difference between Being as Being and the Being of beings.
"The perdurance results in and gives Being as the generative ground...Before the causa sui, man can neither fall to his knees in awe nor can he play music and dance." — (Heidegger, Identity and Difference, p. 72)