Arthur Schopenhauer (1788-1860) was a German philosopher and essayist remembered for his philosophy of Pessimism and for his emphasis on the Will. Though he claimed that the Buddhists had it right in emphasizing the vanity and nothingness of this life, he fancied himself the successor to and rectifier of Kant. Kant had argued that the world which we know is the result of the mind imposing 'form' on sensory input. What causes that sensory input, the 'thing-in-itself', is never known or experienced. Thus, knowledge is never a 'correspondence of what is in the mind with reality', as many common sense philosophers have held. Knowledge is a joint construction of the mind and the 'sensory intuitions' of experience. We don't create reality in our minds, but we form or mold it out of the raw data of sensation.

Schopenhauer believed that the Will opens the door to things-in-themselves. In his view, reality is a representation of the Will. We don't construct our world according to objective rational principles, as Kant held. We construct our world according to the demands of the Will. For example, we see the world as a system of causes and effects not because our minds have grasped the rational order of reality but because this way of seeing the world gratifies the Will. It would remain for Nietzsche, a disciple of Schopenhauer's, to claim that all so-called Truth is a lie, a deception created to satisfy the irrational demands of the Will.

Schopenhauer characterized the Will as a nonrational force driving the ultimately meaningless struggle for existence. Even if we were able to satisfy all of the Will's demands, we would still be unhappy; for, everything ends in disillusion and, ultimately, in death.

One of the more significant notions of Schopenhauer was his idea that much of the drive of the Will is unconscious. Not only is there no ultimate purpose to the aims of the Will, but we are not even conscious of many of our own strivings. He noted that despite the fact that the sexual urge is the strongest drive of human nature, philosophers and other thinkers had almost universally ignored it in their writings. Those who had written of the sexual urge almost universally considered it a scourge. The strongest and most fundamental drive of human beings had been ignored, covered up or condemned, but it was hardly understood. Some had romanticized and idealized sex; others had identified it with evil. But none truly understood that our idea of sex is never more than a representation of the Will. There is no true knowledge of sex; there are only illusions and delusions created to satisfy the Will. Schopenhauer himself thought of sexual desire as like any other desire: satisfying the desire will not bring lasting happiness. He spoke of liberating oneself from the enslavement of desires, yet he also claimed that a person's character is determined by that person's will and what kind of will one has is not in one's control to determine.

He thought scientific knowledge was an invention to help us achieve our desires, that aesthetic experience was desirable because it involved a detached contemplation, a 'will-less' perception (this was taken directly from Kant), and that the morally good person is ego-less, the bad person is egotistical.