Arthur Schopenhauer, answered from the texts and cited to the page.
The whole work rests on a single thought, though that thought requires a book — indeed two volumes and four books — to unfold properly. One and the same world has two aspects, and the task is to learn about it by considering it first as Vorstellung (representation), then as Wille (will), then as representation in an altered fashion, then as will in an altered fashion.1
Begin with representation. Everything the mind is conscious of in experience, knowledge, or cognition of any form — anything present to the mind — is Vorstellung.2 In ordinary experience and in science, we encounter objects ordered necessarily by space, time, and causality; all these orderings are species of the single principle that nothing is without a ground for its being rather than not being, the Satz vom Grunde (principle of sufficient reason).3
Every object is experienced as related to something else that grounds it; every event has a cause; every action traces back to a motive and a character; every truth rests on another truth or on the evidence of the senses. This tells us, exhaustively and with great precision, how the world must appear to us as subjects — but not what the world is apart from that appearance.4
The second book crosses that threshold. The thing in itself — what the world is beyond the aspect that appears to us — is will.5 There is one single essence underlying all objects and all phenomena, ourselves included; the world manifests itself to experience as a multiplicity of individual objects, what I call the objectivation of the will, and each member of that multiplicity, embodying the same essence, strives toward existence and life.6
Human rationality and consciousness are extremely useful and give us an instrumental superiority over other beings, but they are really only a froth on the surface and do not distinguish humanity from the rest of nature at the most fundamental level.7 Our advanced capacities for cognition serve the ends of willing: perception and investigation function primarily to enable us to manipulate objects in order to continue existing and to reproduce.8
As long as we will, we suffer; and that we will, and ultimately what we will, is a function of our inescapable essence, not something rationally chosen, not something we can put an end to by willing.9 The third book returns to representation, but now freed from the principle of sufficient reason. It can happen that we confront objects in a kind of experience out of the ordinary — all the usual relations of space, time, and cause suspended — and we lose ourselves in contemplation, forgetful of ourselves and of the distinction between ourselves and what we perceive.10
This is aesthetic experience: a passive mirroring of the world in which striving ceases and temporary release from pain becomes possible, and in which cognition approaches as closely as it can to the true essence of things, apprehending what I call Ideas, in the sense close to Plato's.11 The fourth book returns to will, but now on an evaluative rather than merely descriptive dimension: the question of its affirmation or negation.12
With self-knowledge achieved, the will can either continue affirming itself — the condition of ordinary existence and its suffering — or turn against itself in denial, the route of the saint and the ascetic, the only genuine escape the world offers.13
one and the same world has two aspects, and we can learn about it by considering it as representation, then as will, then as representation in altered fashion, then as will in altered fashion.The World as Will and Representation Vol 2, p. 14
Schopenhauer uses 'representation' (German Vorstellung) in the same way as his predecessor Kant uses it. It stands for anything that the mind is conscious of in its experience, knowledge, or cognition of any form - something that is present to the mind.The World as Will and Representation Vol 2, p. 14
All the ways in which the world is thus ordered for us are species of the single principle 'Nothing is without a ground for its being rather than not being', otherwise known as the principle of sufficient reason.The World as Will and Representation Vol 2, p. 15
But all of this tells us how the world must appear to us as subjects; it does not tell us how the world is when we try to consider it apart from the way it presents itself to our minds.The World as Will and Representation Vol 2, p. 15
Schopenhauer argues in his Second Book that the thing in itself - what the world is beyond the aspect of it that appears to us - is will.The World as Will and Representation Vol 2, p. 15
His guiding thought is that there is one single essence that underlies all objects and all phenomena, ourselves included, one single way in which the 'riddle' of all existence can be deciphered. The single world manifests itself to experience as a multiplicity of individual objects - Schopenhauer calls this the objectivation of the will - and each member of this multiplicity, embodying the same essence, strives towards existence and life.The World as Will and Representation Vol 2, p. 15
Human rationality and consciousness are extremely useful, and give us an instrumental superiority over other beings, but are really only a froth on the surface, and do not distinguish humanity from the rest of nature at the most fundamental level.The World as Will and Representation Vol 2, p. 15
our advanced capacities for cognition can be explained, for Schopenhauer, as serving the ends of willing: our ability to perceive and investigate the world functions primarily to enable us to manipulate objects that confront us, in order to continue existing and to reproduce ourselves.The World as Will and Representation Vol 2, p. 15
As long as we will, we suffer; but that we will, and ultimately what we will, is a function of our inescapable essence, not something rationally chosen, and not something we have the means to put an end to by willing.The World as Will and Representation Vol 1, p. xv
We find all the usual kinds of relation - space, time and cause and effect - suspended, and lose ourselves in contemplation, forgetful of ourselves and of the distinction between ourselves and what we perceive.The World as Will and Representation Vol 1, p. xv
we apprehend nature in a manner that takes our cognition as close as possible to the true essence of things: we perceive timeless features that run throughout nature, which Schopenhauer calls Ideas, intending us to take this notion in a sense close to Plato's.The World as Will and Representation Vol 1, p. xv
With the world as will, we can either consider it descriptively for what it is, or we can consider it on an evaluative dimension - with respect to its affirmation or negation.The World as Will and Representation Vol 1, p. xiv
What we first notice here is an oscillation between the two key terms from the book's title.The World as Will and Representation Vol 1, p. xiv