I've recently finished reading Being and Time and have attempted to supplement my understanding with different takes on the piece. One interesting angle that I've mused upon myself but haven't seen in the reception history concerning object-subject phenomenology is how Heidegger would address Descartes' notion that reason is needed to understand being as it is.

My hunch is he would bring up disclosedness or a functional candle is a light-source for me, akin to the Heidegger's famous hammer analogy, taking the equipment to its most primordial interface. Going a bit deeper, maybe anticipating that the candle will eventually melt into a pile of wax is akin to Heidegger's take on death, that anticipation on one's finitude affords a more comprehensive understanding of being. However, at this point, I can't tell Heidegger and Descartes apart.


If Heidegger and Descartes are so far apart in terms of their principles of phenomenology, then what objections or criticisms would Heidegger likely have on Descartes' candle example? (going from what we know about Heidegger's ontological leanings in Being and Time).
  • Heidegger would emphasize the earlier disclosed read-to-hand inauthentic thrown phase of the said candle transitioned to a present-at-hand being of authentic distinctness and independence, while Descartes being a skeptical dualist with his eyes seeing these two ephemeral states of material process perhaps would conclude such perceptions from the bodily senses are both illusions which could be transcended by a distinct and clear rational mind... Commented Sep 8, 2023 at 6:18

1 Answer 1


In The Principal of Reason (1957) Heidegger links reason to being, so whereas Descartes says:

“I now know that even bodies are not strictly perceived by the senses or the faculty of imagination but by the intellect alone and that this perception derives not from their being touched or seen but from their being understood” (Descartes 22).

If I hear this right, Heidegger goes a step further and doesn't just say rationalisation makes the being of the wax understood; he says rationalisation makes the being of the wax. Intelligibility not only makes the thing understood, it makes the thing.

Being leads to beings and reason, by rationalising, also leads to beings.

Here is a glimpse of how Heidegger connects reason and being in The Principal of Reason:

[Finally] we hear the principle of reason in a different tonality. Instead of "Nothing is without reason," it now sounds like this: "Nothing is without reason." The pitch has shifted from the "nothing" to the "is" and from the "without" to the "reason". The word "is" in one fashion or another invariably names being. This shift in pitch lets us hear an accord between being and reason. Heard in the new tonality, the principle of reason says that to being there belongs something like ground/reason. The principal now speaks of being. What the principal now says, however, easily falls pray to a misinterpretation. "Ground/reason belongs to being"—one might be inclined to understand this in the sense of "being has a reason," that is, "being is grounded." The popularly understood and presumably valid principium rationis never speaks of this. According to the principal of reason, only beings are ever grounded. On the contrary, "ground/reason belongs to being" is tantamount to saying: being qua being grounds. Consequently, only beings ever have their grounds.

The new tonality reveals the principle of reason as a principle of being. Correspondingly, if we now discuss the principle in the new tonality, we move in the realm of what one can, with a general term, call the "question of being." (p.50-51)

Hence, there is a peculiar state of affairs with the "is" and "being". In order to respond to it, we articulate what the principle of reason says as a principle of being as follows: Being and ground/reason: the same. Being: the abyss. As we remarked, to say "being" "is" ground/reason is inadmissible. This way of speaking, which is virtually unavoidable, does not apply to "being"; it does not hit upon its proper character. (p.51)

The principle of reason is not only a principle in the sense of a supreme fundamental principle. The principle [Satz] of reason is a Satz in the eminent sense of being a leap. [The German] language knows the form of speech: With a vault, that is, with a sudden leap he was out the door. The principle of reason is a vault into the essence of being in the sense of such a leap. We really ought not any longer say the principle of reason is a principle of being; rather, we should say that the principle of reason is a leap into being qua being, that is, qua ground/reason. (p.53)

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