Adler believed the best way for a person to lead his life was through isolation in the stage of adulthood.

Isolation

The state of being separated from others, either physically or emotionally, which can lead to feelings of loneliness.

Stage Of Adulthood

Different phases in the adult life span characterized by unique developmental tasks, challenges, and opportunities, such as young adulthood, middle age, and older adulthood.

Best Way

Optimal method or approach to achieve a specific goal or outcome, often context-dependent and subject to individual or situational variables.