The idea of slave morality was first introduced in “Human, All Too Human” and later explored in greater detail in “On the Genealogy of Morality”, where Nietzsche gives an account of the origins of this moral system and how dangerous this can be. Nietzsche feels that this is particularly important because of the implications that slave morality has had in the European way of thinking, living and acting. The objective of this essay is to first understand the concept of slave morality and then reason why it can be considered a dangerous moral standpoint. Furthermore, we will look for what we ought to replace slave morality with and the main objections and considerations if we were to accept Nietzsche’s ideas.
Nietzsche, like Callicles – an Athenian philosopher well known for his “amoral” position, rejected that the worth of moral values was something that should be taken as given, self-evident or beyond all dispute.  To justify this position, he takes a perspectivist view to argue that objective metaphysics are impossible. He claims that because valuations can’t transcend cultural or subjective formations, objective valuations of truths are impossible.
This perspectivist view extends to the truth and meaning of concepts such as morality, good, bad, evil and any other human concepts that come from the circumstances surrounding an individual or society  – these concepts have suffered a historical evolution. In the first essay of “On the Genealogy of Morals”, Nietzsche takes an historical view on the evolution of the word “good” and he claims that, in all languages, this word has suffered a transformation of ideas. 
What Nietzsche claims to have found was that originally, in Ancient Rome times, the word good actually meant spiritually noble, aristocratic, spiritually high-minded and privileged. The word good was used to describe the powerful and the aristocrats – “the masters”. On the other end of the spectrum, bad was the word describing the opposite or absence of good, meaning common, vulgar and low and this was often associated with plebs and slaves. This meaning of good/bad was characteristic of the aristocratic mode of valuation. It is fundamental to note that these two words were merely a statement of a particular social position, devoid of moral connotation. 
Nietzsche then claims that another mode of valuation branched off from the aristocratic mode of valuation, called the priestly mode of valuation. He argues that this arose as a response to the differences in power between the priestly caste and the warrior caste. What happens is that the heightened differences in power and possible oppression from the powerful (masters) made the priests and those who were powerless develop a venomous hatred and resentment towards those in power. 
The priestly values start out with the opposition of pure and impure. Initially, a pure man is simply “a man who washed himself, who forbids himself of certain foods (…), who had a horror of blood”.  But these were also the characteristics of the priestly caste, and thus, priests called these good. At the same time, the word evil appeared to describe the behaviours that were contrary to what priestly people were themselves. With this, there was a process of revaluation of values, where good took a whole new meaning. According to Nietzsche, the “slave revolution” had origin when “the Jews, in opposing their enemies and conquerors were ultimately satisfied with nothing less than a radical revaluation of their enemies’ values, . . . an act of the most spiritual revenge” . What was achieved from this spiritual revenge was the redefinition of good and bad (now labelled as evil), with a clear moral connotation. The characteristics of the “slaves”, humility, kindness, sympathy, become the ones that were praised. It happened to be that, from the slave morality’s perspective, “only those who suffer are good; the poor, the powerless, the low are the only good people; the suffering, those in need, the sick, the ugly are also the only pious people; only they are blessed by God” , and in turn, the privileged and powerful people, are the evil, cruel, lecherous, the godless.
The way Nietzsche justifies that slave morality is a dangerous position is by appealing to the origins of this morality, particularly, by pointing out to one of the foundations of this slave morality – resentment. For Nietzsche, slave morality is created when “resentment itself becomes creative and gives birth to values”. What he claims is that, in juxtaposition with the noble morality, developed from the affirmation and pride in oneself, slave morality was born out of resentment and hatred. Such morality rejects the exterior and what is different. In fact, the whole grounding of slave morality comes from the existence of a hostile external world. Comparing with the master morality, where one would seek revenge through action, a slave would seek revenge through the imaginary – which in turn, needs enemies in order to exist. What happens is that slaves deceive themselves into thinking they are the good and the strong are the evil. 
Another characteristic of the slave morality is that it is “life denying” – slave morality preaches for contempt and acceptance, forbidding actions that are natural to humans. In the light of this morality, “everything becomes more dangerous, not only cures and remedies, but also arrogance, revenge, acuteness, profligacy, love, lust to rule, virtue, disease.”  The natural impulses of humans are suppressed and are drawn away from action, turning hatred inwards, making it deeper and more evil. Taking Christianity as an example, a form of slave morality for Nietzsche, he describes “‘the Christian faith” as “a sacrifice of all freedom, all pride, all self-confidence of the spirit; at the same time, enslavement and self-mockery, self-mutilation”.  Nietzsche goes further and argues that, given the nature of the slave morality, which is a morality that rejects the values from master morality, it must follow that when nobles would affirm life and enjoy living it, the slave morality would reject embracing life. 
Furthermore, Nietzsche argues that slave morality is repressive of the ones who are naturally more talented, the higher individuals, stating that “everything that elevates an individual above the herd and intimidates the neighbour is called evil” . This type of morality hinders progress and independent thinking, advocating complacency and comfort. We can find similarities with this line of thought and Callicles’, who claimed that morality was just a measure of prudence of the weak, unable to do what the strong do, choose to protect themselves from the actions of the strong by banning them. 
One of the core points of his criticism was that slave morality was the predominant morality in the XIX century Europe. One of his concerns was that slave morality would ultimately lead individuals into a Nihilist position, as the constant search for an objective morality – something that Nietzsche considered impossible, given he rejected objective truths – and not finding it would make individuals unable to believe in anything. For Nietzsche, Nihilism is the natural extension to the dualist view of morality.
Nietzsche’s critiques on mass morality are put quite clearly in “Daybreak”. He questions why one becomes moral and points out that “submission to morality can be slavish or vain or selfish or resigned or obtusely enthusiastic or thoughtless or an act of desperation, like submission to a prince”. In the same line of thought, he criticizes the blind acceptance of faith as accepting faith out of customs is to be dishonest, coward and lazy. He asks the reader: “Could these be the presupposition of morality?” 
It is to note, however, that Nietzsche admits that it is only with the introduction of good and evil that humans finally become an interesting creature. 
But then we must ask: with what should we replace slave morality? Nietzsche has an interesting conception of this. His philosophy is not a political philosophy, he differs from other moral philosophers as he is not trying to give us a method to follow and be moral.  In fact, he questions the real value of morality because to him, moral values are manifestations of a deeper physiological condition, physiological state or attitude toward life, not something that stand on their own.
In some of his later works, he places a strong focus on affirming and feeling the power of life and on becoming better, individually. What I believe he means is that higher individuals should forge their own morality and release themselves from the herd morality. Here, it seems he adopts a moral relativist view, where the individual is allowed to do anything as long as it’s his own morality.
He introduces the key concept “will to power”, which might’ve been what Nietzsche believed to be the main driving force in man: achievement, ambition, the striving to reach the highest position in life. As such, embracing life would be embracing “will to power”.
Although seemingly approaching Social Darwinism, Nietzsche’s conception of “way of living” is not the survival of the fittest itself, but the expansion of life, rejecting moral systems and even laws that are aimed for the herd. Nietzsche makes a brutal distinction between weak/lower and strong/higher individuals. He accepts the need of slave morality for the weak, but this type of morality, a morality-for-all is harmful to the exceptional people – these should follow their own inner law.
It is worth noting that Nietzsche doesn’t advocate the master morality either, as he disapproves of crude hedonism and claims self-control as essential.  In fact, for an authentic life, one should liberate himself from trivial pleasures and discover new, higher ones. We can ask: what are these higher things? Nietzsche rejects that faith –in patriotism, art, religion, for instance, are the higher things. He tries to abolish the need of fundamental truths and with that, to abolish a world that is created from our need for comfort and certainty. He advocates for an active and relentless scepticism, where “the spirit would take leave of all faith and every wish for certainty, being practiced in maintaining himself on insubstantial ropes and possibilities and dancing even near abysses“. 
Through the study of Nietzsche’s method, could one argue that there is any one definition of good that is better than another definition of good? Could we speculate that rather than the concepts of good and bad being purely human constructions, that we are actually approximating a conception that is better than the previous one? Nietzsche would point out the evolutionary character of concepts to show their subjectivity. However, could this evolution have a direction towards something that is in essence better, rather than just unjustified whims of particular culture or society? Could it be that the current conception of “good” is actually better than (for example) the Roman conception of good, regardless of its initial origins? However, Nietzsche’s perspectivism would ask “What do you mean by better?”
The brutal nature of Nietzsche’s views on equality and democracy seem to throw humans back into the wild, where the naturally stronger are completely entitled to exploiting the weaker. Could it be that there is something inherent to human nature that makes us feel natural sympathy towards other human beings, like David Hume suggests? But perhaps, this conception of sympathy towards others itself is derived from the 2000 year old Christian morality, that is so ingrained in society that leads us to believe that “sympathy” is something innate. Even so, the master morality leaves a lot to desire as it seems to throw humans back into the animal kingdom where only the strongest is supposed to prevail. However, Nietzsche would respond that he himself isn’t advocating the return of the master morality, pointing that the “overman” wouldn’t take pleasure in plain vain or hedonistic actions.
There is also criticism in the method Nietzsche uses to criticize the slave morality, recurring to an “ad hominem” argument to dismiss this type of morality. However, by taking a perspectivist view, Nietzsche makes it impossible to separate the morality from the person/collective that generates that morality. 
His perspectivism and his negative criticism to moral theory became the roots of various movements such as modern relativism in moral theory. In my opinion, I believe it would be incredibly contradictory if Nietzsche gave us anything even close to a moral theory with the purpose to replace the slave morality. What Nietzsche does is to invite the individual to find out their own truth and their own morality, by showing that whatever seems to be granted or self-evident is actually not; all concepts, including morality and moral values are in fact, just a product of human evolution.
 Nietzsche, Friedrich. 1887. On the Genealogy of Morals – A Polemical Tract
 Lindstedt, David. 1966. The progression and regression of slave morality in Nietzsche’s Genealogy: The moralization of bad conscience and indebtedness
Nietzsche, Friedrich. 1886. Beyond Good and Evil, translated by Walter Kaufmann
 Barney, Rachel, “Callicles and Thrasymachus”, The Stanford Encyclopedia of Philosophy (Winter 2011 Edition), Edward N. Zalta (ed.)
 SparkNotes Editors. “SparkNote on Friedrich Nietzsche (1844–1900).” SparkNotes.com. SparkNotes LLC. 2005. Web. 25 Apr. 2012.
 Nietzsche, Friedrich. 1881. Daybreak: Thoughts on the Prejudices of Morality
 Nietzsche, Friedrich. 1882. The Gay Science
 Kate Olson “Perspectivism and Truth in Nietzsche’s Philosophy:A Critical Look at the Apparent Contradiction”
 Priestly people