Final answer:
Jean-Paul Sartre's statement means that when an individual makes a choice for themselves, it also affects all of humanity.
Step-by-step explanation:
In his philosophy, Jean-Paul Sartre argues that when an individual makes a choice for themselves, they are also making a choice on behalf of all humanity. This means that each decision we make has an impact not only on ourselves but on the world and other people as well. For example, if a person chooses to act with honesty and integrity, they are setting an example for others to follow, thus influencing the moral choices of society.