How did Buddhist ideas influence Arthur Schopenhauer’s pessimism?

Arthur Schopenhauer’s philosophy was not directly influenced by Buddhism in its initial formation, but rather by the Upanishads and the philosophy of Vedanta, which he encountered in 1813–14. While he is often associated with Buddhism due to the thematic parallels in his work, his system is primarily a synthesis of Kantianism and these Indian traditions.12

Schopenhauer’s pessimism posits that the world is a manifestation of an irrational, insatiable "will-to-live," which inherently results in suffering. His alignment with Buddhist thought is found in his conclusion that this suffering is caused by striving and desire. Just as Buddhist philosophy seeks the cessation of such striving through nirvana, Schopenhauer’s ethics point toward the "negation of the will"—a state of liberation achieved through asceticism, compassion, and the abandonment of ego-driven desires. Thus, he viewed the world as fundamentally unhappy, valuing the nonbeing of the will’s negation over the misery of existence.12