Step 1: J.S. Mill's Concept of Coercion.
John Stuart Mill advocated limiting individual freedom only to prevent harm to others. He justified coercion based on self-preservation: individuals can be coerced if their actions endanger the safety or well-being of others or society.
Step 2: Option Analysis.
- (1) Justice: While a moral principle, justice is not Mill's sole basis for coercion.
- (2) Self-preservation: Correct. Mill argued coercion is rationally justified to protect the self-preservation of others.
- (3) Happiness: Coercion, for Mill, is not justified to promote happiness.
- (4) General Will: This concept belongs to Rousseau, not Mill.
Step 3: Conclusion.
The correct answer is (2) Self-preservation.