The absolute is a scholarly paraphrase for God. Like God, the absolute is thought of in many ways. It’s not a synonym for God. “to be absolute” has a meaning of its own by which scholars and mystics wanted to hint at the nature of God. In the first place, the meaning of “absolute” has been shaped by Plato. Plato in turn was certainly shaped by other sources, but as we know too little about them, I focus first on him.

Plato argued there are entities inaccessible by perception that he called eide, forms or ideas. We have to assume them as existing because otherwise we would have no experience-independent knowledge. Such is knowledge of mathematics, logic, and virtues that includes knowledge of why we ought to be virtuous. Forms, Plato said, are separate, chôristos, from the perceivable world. Greek chôristos is Latin absolutus. The meaning of this word is preserved in modern usage. Rulers are absolute if they are removed from the ruled the rules apply to; you are absolutely right if your claim is removed from doubt, and a vodka is absolute if it is beyond ordinary spirits.

Plato made further claims that shaped the meaning of “absolute”. First, ideas enable us to know not only virtue, logic, and mathematics but anything knowable. Second, ideas not only enable us to know anything but also enable everything to be. There is no reason for anything to exist, he argued, unless there is something it exists for, and this is its idea. Third, just as anything perceivable can be known and exist only by its idea, so any idea can be known and exist only by the idea of ideas, which he identifies as the form of the good . So everything exists for and because of the good. The good is the unconditioned condition of any knowledge and existence, the ultimate cause, reason, and ground of everything that explains everything there is and justifies all obligations. Plato compared it to the sun, which as the perceivable source of light and power is the unconditioned condition of sight and of all perishable existence, just as the idea of the good is the ultimate ground of all knowledge and anything that exists in the realm of the imperishable and the perishable.

Aristotle took up Plato’s claims on the one absolute in his concept of God as the unmoved mover, condensing Plato’s descriptions and suggestions into the concept of something causing everything without being caused or having a reason. The two philosophers shaped what became the metaphysics of the Middle East and the West: a theory that explains all facts and existence itself, justifies all valid norms and why there is obligation at all, and provides meaning to what is and ought to be. This threefold unconditioned source of facts, obligations, and meaning is the absolute. It provides an attractive ultimate answer to the otherwise unending series of why-questions we humans ask, most often perhaps when we are kids.

Following Aristotle, metaphysics is defined as both a “discipline concerned to identify the first causes” and “the science that investigates being qua being” (Loux 2002: 4). It can be defined both ways if we expect first causes to entail properties of being qua being, and vice versa. Yet can we today still seriously believe metaphysics can be rational? I presuppose any rational theory has to indicate its potential falsifiers. If metaphysics is rational, it needs potential falsifiers, and if it differs from other rational theories, its falsifiers must differ from those of physics and moral theory. With most philosophers today, I assume that the potential falsifiers of empirical science are observation data, which we may also call empirical intuitions. With Rawls (1971: 46ff), I assume that the potential falsifiers of moral theory are moral intuitions.

What then are the potential falsifiers of metaphysics? Take a paradigmatically metaphysical question, such as whether there is a world existing independently of (our) mind or not. It cannot be decided, I guess, without recourse to intuitions about what is more meaningful: that the world is nothing but a content of my own private consciousness, or something existing independently of us that has somehow produced us and can be explored by us (cp. Loux 2002: 250–291). Metaphysicians compete in presenting their arguments so as to show that their theory makes more sense of facts and intuitions that we are not willing to abandon.

How can arguments be more or less convincing in issues as dark or deep as metaphysics? We should not expect them to be only logical in a narrow sense. Plato used what also novelists and playwrights use in suggesting ideas about the meaning of it all: myth and allegory, satire and irony. It’s a way to expose claims as ridiculous or similarly unacceptable, or as rational, reasonable, resonating with what we recognize as being ourselves, or as authentic. I’ll use this way myself in the last section of this book.

I distinguish between descriptive and normative metaphysics, between last explanations of facts and last justifications of obligations, and correspondingly between descriptive and normative absolutes. To find an ultimate ground both for all facts and obligations meets our desire for simplicity, but justifies everything there is, not only the good but also evil things. As the later Muslim, Christian, and Jewish philosophers understood Aristotle’s ultimate ground as the omnipotent and omnibenevolent creator god of their holy scriptures, Aristotle seemed to imply that the ultimate ground is also the ground of all evil.

This consequence (leading, as we’ll see, Leibniz and Hegel to present evil as ultimately good) was a motive to distinguish causes that explain facts from reasons that justify norms. The distinction favored, and was favored by, natural science. Science forbids explanations by divine purposes. It allows only causal explanation and leaves discussion of reasons or teleology to theology and metaphysics. Kant and most scientists denied science the ability to find the descriptive absolute because any causal explanation seems to lead to another question of what caused the cause. Yet physicists who today strive for a theory of everything (a ToE) hark back to the former ambition of finding a descriptive absolute. Moreover, the distinction between explanation and justification may be compatible with rational teleology, as I’ll argue in the last section.

In any case, whether the ultimate ground of everything is conceived as one or as on the one hand explaining all facts and on the other justifying all obligation, it is itself unexplainable, unjustifiable and without cause, reason, or why. Yet if we cannot avoid accepting a terminal of explaining and justifying, why not assume that already in our ordinary world, some facts and values cannot be explained and justified, that they are without a why and in this sense absolute? That the absolute is in this world belongs to the ideas that make up modernity. Kant, Hegel, and Heidegger belong to the thinkers who developed this assumption. By using the plural form absolutes in the title of this book, I want to indicate that there are various forms to conceive ultimate grounds, descriptive and normative and transcendent and immanent ones. I have to add that I vet normative absolutes, though I keep in mind implications concerning the descriptive absolute.

One motive for my interest in normative absolutes are my doubts about the presently prevalent way of justifying obligation. The modern and still prevalent way is to justify obligation by appeal to rational agreement (Hobbes 1651 [1968]; Habermas 1992 [1996]; Scanlon 1998). This approach presupposes that under conditions of equality and transparency, the rationality of an agreement guarantees its morality. Yet this allows the living generations to rationally agree on admitting misuse of natural resources. It underrates the weight of moral intuitions that the living have to care for future generations, even to preserve human life.

Such duties may seem to be better taken account of by naturalists such as Kitcher (2011) and Tomasello (2016), who explain and justify morality as a result of the evolution of the human species; by moral psychologists who, starting with ...