Final answer:
Jean Paul Sartre is the philosopher associated with the idea of existentialism, which emphasizes human freedom and individual responsibility in shaping one's life.
Step-by-step explanation:
The philosopher associated with the idea of existentialism is Jean-Paul Sartre. Existentialism is a philosophical belief that emphasizes human freedom and the individual's responsibility for shaping their life and giving it meaning. Sartre's ideas focus on the concept of existence preceding essence, which means that we first exist and then create our own essence through our choices and actions.