Kierkegaard evidently read Descartes, because he objected to the latter’s famous argument, “I think, therefore I am”, and the notion that doubt is derived from knowledge. It might appear that the two of them belong to different camps, but I have reason to believe that Descartes influenced/inspired Kierkegaard in his conception of “subjective certainty”.
It was Descartes who first brought “subjective certainty” to the forefront of philosophical thought, although he didn’t use the term explicitly. His seminal treatise “Meditations on First Philosophy” is, among other things, a demonstration of the pursuit of subjective certainty.
Descartes is certain of three things:
1. his own existence
2. his knowledge of geometry
3. the existence of God
The first, his own existence, is evident to his conscious mind. No logical proof necessary. It is, nevertheless, subjective and existential, not objective.
The second, knowledge of geometry, is objective truth, independent of his existence or awareness. However, Descartes can appropriate the knowledge as his own, and thereby attain to a type of subjective certainty. To do that, he cannot simply memorize the conclusions of geometrical deductions, like children parroting adult speech, but he must be able to make those deductions himself, by fully understanding the inner intricacies of geometry. Once he does that, he has taken full ownership of the knowledge, and can build upon it further. The whole body of mathematical knowledge would resemble an organic growth with each mathematician contributing his part.
Up to this point, there are no objections to Descartes’ certainties from either atheists or scientists. All men possess certainty of the first kind, and Descartes addresses them in a language of the common people, French; some elite possess certainty of the second kind, Descartes addresses them in Latin, the language of the learned. He then proceeds to proclaim, in Latin, and prove in the manner of geometrical deduction, that the existence of God is as “clear and distinct” to him as his own existence and his knowledge of geometry. In other words, he is as certain, if not more so, of the existence of God, as his own existence and his knowledge of geometry. The reaction? People either stopped paying attention, or raised objections of all sorts.
It dawned on me, as I was mulling over this, that Descartes was getting at the true nature of certainty. What exactly is certainty? What do we really mean when we say that we are “certain” of something?
Certainty is the feeling or manifestation of a firm relation.
Certainty does not lie in the senses or the corporeal world, because they’re in a state of constant flux. It is impossible to be certain of something that is constantly in flux, just as it is impossible to build a solid foundation in sand.
All of us are certain of our own existence, because we are necessarily always related to ourselves; Some scientists are certain of scientific truth, as they have grasped the knowledge firmly; Some are certain of the existence of God, being firmly related to Him, or in the words of Kierkegaard, “grounded in God”.
Doubt is the feeling or manifestation of an unstable relation.
Descartes’ method of doubt is not the doubt of the skeptics, who suspend all their judgments, but a method of elimination like that of Socrates. He eliminates false opinions by proving their incompatibility with knowledge that are certain.
Being in doubt, in the manner of true skeptics, is being in suspense, and to doubt all things is to be always in suspense, and never enter into a firm relation with anything, not even oneself. It is a very unstable state and very difficult, if not impossible, to maintain. Eventually, a stable relation must be established, and one becomes either grounded in truth or entrenched in falsehood.
When our relation to ourselves is out of balance, we experience self-doubt, and despair is the entrenched state, as Kierkegaard wrote in The Sickness Unto Death; When our relation with God is non-existent or unstable, doubt is the symptom. This doubt does not originate from God, who is everlasting and immutable, but from ourselves, the fickleness of our nature and our free will. It can be and must be resolved into one of two states, either faith or unbelief. When the heart becomes hardened and the neck stiffened, one is entrenched in unbelief. This is why Kierkegaard insists that doubt and unbelief are the result, not of knowledge, but of choice.
I tend to think that the increasing sense of uncertainty and the breakdown in human relationships also result from the fickleness of human nature. Divorce is forbidden, precisely because fickleness and restlessness are the opposite of the Divine Nature, but it was permitted, because of the hardness of our hearts.
For a Christian, the pursuit of certainty is none other than the pursuit of God. In the words of St. Paul, “that I may lay hold of that for which Christ Jesus has also laid hold of me.”