[1] In Beyond Good and Evil, Nietzsche accuses past philosophers of lacking critical sense and blindly accepting dogmatic premises in their consideration of morality.
The work moves into the realm "beyond good and evil" in the sense of leaving behind the traditional morality which Nietzsche subjects to a destructive critique in favour of what he regards as an affirmative approach that fearlessly confronts the perspectival nature of knowledge and the perilous condition of the modern individual.
He then contests some of the key presuppositions of the old philosophic tradition like "self-consciousness", "knowledge", "truth", and "free will", explaining them as inventions of the moral consciousness.
In their place, he offers the "will to power" as an explanation of all behavior; this ties into his "perspective of life", which he regards as "beyond good and evil", denying a universal morality for all human beings.
Religion and the master and slave moralities feature prominently as Nietzsche re-evaluates deeply held humanistic beliefs, portraying even domination, appropriation and injury to the weak as not universally objectionable.
He offers an entirely psychological explanation of every past philosophy: each has been an "involuntary and unconscious memoir" on the part of its author (§ 6) and exists to justify his moral prejudices, which he solemnly baptizes as "truths".
Spinoza masks his "personal timidity and vulnerability" by hiding behind his geometrical method (§ 5), and inconsistently makes self-preservation a fundamental drive while rejecting teleology (§ 13).
His "faculty" to explain the possibility of synthetic a priori judgements is pejoratively compared to a passage from Molière's comedy Le Malade imaginaire in which the narcotic quality of opium is described in terms of a "sleepy faculty" – according to Nietzsche, both Kant's explanation of synthetic a priori judgments and Moliére's comedic description of opium are examples of redundant self-referring statements which do not explain anything.
"Free spirits", by contrast to the philosophers of the past, are "investigators to the point of cruelty, with rash fingers for the ungraspable, with teeth and stomach for the most indigestible" (§ 44).
Nietzsche appears to espouse a strong brand of scientific anti-realism when he asserts that "It is we alone who have fabricated causes, succession, reciprocity, relativity, compulsion, number, law, freedom, motive, purpose" (§ 21).
He finds the English coarse, gloomy, more brutal than the Germans, and declares that "they are no philosophical race", singling out Bacon, Hobbes, Hume and Locke as representing a "debasement and devaluation of the concept 'philosopher' for more than a century" (§ 252).
In a prophetic statement, Nietzsche proclaims that "The time for petty politics is past: the very next century will bring with it the struggle for mastery over the whole earth" (§ 208).
Other subjects touched on include his doctrine of the eternal recurrence (§ 70), music (§ 106) and utilitarianism (§ 174), among more general attempts at trenchant observations about human nature.
The work concludes with a short ode to friendship in verse form (continuing Nietzsche's use of poetry in The Gay Science and Thus Spoke Zarathustra).