On the other hand, a second question arises: is not nihilism, whose power of negation affects everything, similar to scepticism, is not it a kind of scepticism?

Here again, I believe that these two forms of thought are incommensurable. Scepticism doubts the possibility of truth. Nihilism puts its stamp not on the notion of truth, but on the notion of value.
On the other hand, and this is the most important point, the sceptic doubts everything, and does not even know if the truth is attainable or not. Through epoché, he no longer takes a position, in other words, he no longer judges or affirms. On the contrary, nihilism asserts loud and clear that nothing has value. It is all certainty. It claims to be knowledge.

So we see: nihilism is a way of thinking that is irreducible to pessimism and scepticism, a confusion that we suspect is constitutive of modern thought. It is a mode of thought whose specificity must be grasped in its own right.

Once nihilism has been better identified in its theoretical aspect, we then realise that there is a philosopher who was explicitly nihilist, or at least explicitly displayed the nihilist position. In other words, there is a Manifesto of Nihilism in the history of philosophy, and we can understand it as such now that we have a better idea of what nihilism is.

Surprisingly, perhaps extraordinarily, we find him at the very beginning of the emergence of philosophy as a way of thinking and a way of being: the first philosopher, Thales. Here is what we find in a fragment: Death is not different from life he said – So why are you not killing yourself? someone said to him. Because, he replied it does make no difference ¹.
If we accept that it is not only an identity of essence between life and death that Thales wishes to signify, but also an equality of value, then what can we deduce? Not that Thales was a nihilist. That we do not know, and perhaps we would be doing him the injustice of attributing to him a thought that he did not have, committing an anachronism. However, Thales expresses in a particularly clear way what could be a dialogue with an authentic nihilist: he would not answer anything else.

We also find this idea in Cioran, who sometimes displays, in the midst of classic pessimistic musings, for example: Wouldn't it be better if I buried my tears in the sand on a seashore in utter solitude? But I never cried, because my tears have always turned into thoughts. And my thoughts are as bitter as tears ² genuinely nihilistic musings, for example: Although life for me is torture, I cannot renounce it, because I do not believe in the absolute values in whose name I would sacrifice myself. If I were to be totally sincere, I would say that I do not know why I live and why I do not stop living. […] Why should I bother? Let death appear in a ridiculous light; suffering, limited and unrevealing; enthusiasm, impure; life, rational; life's dialectics, logical rather than demonic; despair, minor and partial; eternity, just a word; the experience of nothingness, an illusion; fatality, a joke! ³.

Cioran is therefore aware that the traditional solutions of pessimism - despair, tears - are of no help to him, because to do so would be to confer a value on them, and that the axiological position he defends forbids him from doing so. He obscurely senses that he is in a completely different sphere from classic pessimism, and he lacks the words to express the radicalness of the position he has reached: I do not know whether I am desperate or not, since lack of hope does not automatically imply despair. I could be called anything because I stand to lose nothing. I've lost everything! flowers are blooming and birds are singing all around me! How distant I am from everything! ⁴.

At one point, he succeeds magnificently in linking, in the same sentence, the content of nihilism and his awareness of its radical nature: Why don't I commit suicide? Because I am as sick of death as I am of life. I should be cast into a flaming caldron! Why am I on this earth? I feel the need to cry out, to utter a savage scream that will set the world atremble with dread. I am like a lightning bolt ready to set the world ablaze and swallow it all in the flames of my nothingness. I am the most monstrous being in history, the beast of the apocalypse full of fire and darkness, of aspirations and despair. [...] My symbol is the death of light and the flame of death. Sparks die in me only to be reborn as thunder and lightning. Darkness itself glows in me ⁵.

1. Lives and Opinions of Eminent Philosophers, Book 1
2. On the heights of despair, Nothing is important
3. Ibid.
4. Ibid., I do not know
5. Ibid., The monopoly of suffering