Arthur Schopenhauer (1788-1861) brought Buddhism into his philosophy and made something of a break with Christianity. The break followed a period as a boy boarding in Wimbledon where he despised the pleasantness of tone within the Christian worship. After his father's death, his mother lived in Wiemar where he was given the Upanisads which he found elevating. However, his views became closer to some interpretations of Buddhism than Hinduism.
Like Kant he believed that nothing was outside from and independent of consciousness. Rather the intellect in the mind moulds the shape of the world. But he also believed that the will was stronger than the intellect, not quite so dissimilar to Freudian ideas later. The idea of the will also fits in with the amorality and self-drive of Darwin's mechansim of the survival of the fittest. The will to live overcomes rationality with its purposes, and includes the sex drive, because the sex drive is the means to reproduce and drives conscious and unconscious activity. So whilst we may think we are pursuing happiness with this sex drive, in the pursual of the mate, happiness is really a deceptive tactic by which we think we are motivated in the reality of pursing reproduction and death. This dillusion of happiness constitutes the suffering that is life.
There are two ways to overcome such suffering. Death is its release, or there is the achievement of the denial of the will to live. The method is to develop disinterestedness through compassion for others and through contemplating art.
Whilst the religions make the mistake of teaching as if their doctrines are true instead of allegorical, they work as a means to a spiritual end of conquering the will to live. Spiritual lives always demonstrate the same characteristics whatever the religion. This is through using inward and direct intuitive knowledge. The way they portray themselves, however, leads on to deception which adds to the general gloom. Extinction of the will leads to extinction of the representation of the world, and true happiness can follow.
This is similar to Buddhism, that the world as seen is a surface not a true condition. It cannot be true in Buddhism, because it is changing and craving for its permanence leads to suffering. So Buddhism focusses upon transcience, and then the misapplied craving, whereas Schopenhauer is more psychological and mind focussed throughout. However, for the suffering of life might be substituted samsara, for will to live can be substituted craving, and for the extinction of the will, there is nirvana. In essence Schopenhauer's view of life is Buddhist, yet Western and without the cultural trimmings of much of Buddhism. However, whereas Buddhism has an orthopraxy of an active spiritual life, Schopenhauer is basically a thinker and there is no such programme.