c) Is nihilism a kind of skepticism?

Nietzsche certainly does not equate nihilism with scepticism, because for him scepticism is not an illness but, on the contrary, a strength of will and thought. Scepticism is a symbol of strength, insofar as it embodies honesty of thought: I put aside a few sceptics, the types of decency in the history of philosophy: the rest haven’t the slightest conception of intellectual integrity ¹.

Above all, scepticism is synonymous with fortitude, because it does not allow itself to be locked into a belief, whereas the need for belief, like any need, is synonymous with weakness:
Do not let yourself be deceived: great intellects are sceptical. Zarathustra is a sceptic. The strength, the freedom which proceed from intellectual power, from a superabundance of intellectual power, manifest themselves as scepticism. Men of fixed convictions do not count when it comes to determining what is fundamental in values and lack of values. Men of convictions are prisoners. […] On the contrary, the need of faith, of something unconditioned by yea or nay, of Carlylism, if I may be allowed the word, is a need of weakness. The man of faith, the “believer” of any sort, is necessarily a dependent man—such a man cannot posit himself as a goal, nor can he find goals within himself ².

The scepticism that Nietzsche has in mind here is perhaps that of Montaigne, with whom he seems to have had deep intellectual affinities ³. We know that, on Christmas Day 1870, Nietzsche received Montaigne's Essays from Cosima Wagner. On several occasions, he declared: Basically it is a small number of the older Frenchmen to whom I return again and again and explicitly refers to the author of the Essays: I have something of Montaigne’s mischievousness in my spirit, who knows? Perhaps also in my body ⁴. Like Montaigne, who saw himself as always learning and making trial ⁵, Nietzsche claimed for himself the perilous prerogative of spending a life in experiment and of running adventurous risks ⁶.

In fact, what brings nihilism and scepticism together, and seems to make them comparable to each other for some authors (such as B. de Saint-Sernin, as we have seen), is the radical rejection of the world to which they both seem to lead. It is this point in common that we will retain as justification for bringing them together.

d) Criticism of this confusion of nihilism with pessimism and scepticism

These difficulties arise perhaps only because we have assimilated the authentic meaning of nihilism with its historical meaning. Now we see that this meaning fluctuates, and that it is attributed to doctrines that may not be nihilistic. In other words, the search for nihilism is based on a study of examples of what is considered nihilist, without being sure. The logical vicious circle is obvious.

We therefore prefer another method. We will discard the alleged examples of nihilism, since we are not sure that they are really nihilistic. So we will not seek the meaning of nihilism from the study of pessimism, or Christianity, and so on. The problem then arises: from what can we seek the meaning of nihilism, now that we seem to have deprived ourselves of the only means of grasping it? In fact, we will examine nihilism on the basis of the only thing we know about it: its name, "nihilism".

What does 'Nihil' actually mean, the 'nothing' that nihilism conveys in its very name? What is the "nothing" of the man of "nothing"? We think it refers to the following proposition: In fact, if we grasp the reality of things, nothing has any value, really, objectively.

From this initial definition, which nihilism conveys in its very name, we can use the principle according to which a concept only really has a meaning if it is distinct from other neighbouring concepts. Instead of assimilating it directly to scepticism, pessimism or Christianity, which would make it disappear instead of enriching its meaning, we will look to see if it can be distinguished from all these doctrines.

Pessimism can be defined as the axiological doctrine which holds that life, the world and things have no value, and which therefore falls into the mode of being of sadness, resentment and suicide. This brings us to the radical difference between pessimism and nihilism: if nihilism claims that life, the world and things have no real value, it similarly claims that death, sadness, resentment and nothingness have no real value either. Indeed, as "contents of meaning", death and sadness suffer the fate that the nihilist inflicts on all contents of meaning: the deprivation of all real value. Admittedly, this distinction seems purely formal, even sophistical: it is like splitting hairs, it seems. I think it brings with it a major consequence: nihilism is not pessimism.

Indeed, pessimism is that doctrine which considers sadness or death to have great value, insofar as, for example, they are the only authentic attitudes of the wise man (even if this doctrine does not say so explicitly, without using the concept of value verbatim). As such, it is one of those thoughts that "still give value to something".
The nihilist has the specificity of being the only one who places no value on anything, on any content of meaning. He attributes meaning, truth, to things and concepts, but no value. He therefore stands on radically different ground, which needs to be thought through.

Nihilism, as Nietzsche presents it, is not authentic nihilism, but classic pessimism, since the author tells us that it is by noticing that his three ideals - purpose, unity, truth - are not embodied in the real world that the "nihilist" comes to despair of the world. It is on the basis of his ideal that the "nihilist" condemns the world, so Nietzsche paints us a portrait of a nihilist who has ideals - a true contradiction in terms - in other words, who still places a value (and the greatest!) on many things.

This meaningless conception of an idealist nihilism is reflected here: The philosophical nihilist is convinced that all that happens is meaningless and in vain; and that there ought not to be anything meaningless and in vain. But whence this: there ought not to be ⁷.

So we can see how pessimism and nihilism can in no way be confused, and form two consistent axiological positions: whereas nihilism is the denial of the value of any content of meaning=X, pessimism gives value to certain actions and thoughts, and the origin of its painful feelings and negative thoughts can even be... an ideal.

1. The Antichrist, 12
2. The Antichrist, 54
3. N. Panichi, in the Revue Noésis, n°10, 2006, p.93-112
4. Ecce Homo, Why I am so clever, §3
5. Essays, II, 2, 805 B
6. Human, All Too Human, Preface, §4
7. The Will to power, Book 1 : the European Nihilism, 36, p. 49