Nietzsche thinks he cares more about truth than other philosophers do. This is partly because he is not in thrall to a moral bias, but also because he understands better the kind of truth there really can be—the kind humans can and do have. So he rewrites philosophers’ previous idea of truth while still giving it preeminent value.
In announcing these truths he contributes to what he thinks is a prolonged, ineluctable process by which our modern scientific will to truth finally faces the truth about values—the last and hardest topic for it to face. As these truths are exposed, our culture, and the rest of the world through it, is confronted with a great spiritual crisis and challenge: How can and will we go on to value once we have uncovered these truths about our valuing? How can we value, now for the first time, honestly (i.e., while facing the truth about what we’re doing)?
It is extremely difficult to do so because this truth tends to undermine our [values] […] insofar as they involve a framing claim that these things (that are valued) are really, independently good. For the truth, Nietzsche holds, is that all values are dependent on valuings—are “perspectival.”
Recognizing Nietzsche’s idea of values as signs is the key to much of his thought about them. Seeing a value as a sign, we see why he insists that it’s not only humans that value. Animals are clearly responsive to signs in their perceptual discernments. So a predator may employ a certain smell as a sign of prey. And we can see ways that plants are responsive to signs as well. Nietzsche holds that willing (or aiming) is something that all organisms do. It depends not at all on consciousness.
Our human values, as worded, are distinctive in being held in common, as norms. They are accepted because this is “how one values” in the community to which one belongs. They thus serve a “herding” function, which strengthens the group but at the expense of members’ individuality.
John Richardson, Nietzsche’s Values, Preface