Step 1: Understanding Kant’s Moral Philosophy.
Immanuel Kant, a pivotal modern philosopher, is recognized for his deontological ethics, which posits duty as the foundation of morality. His principle "Duty for Duty's Sake" dictates that actions are morally permissible if undertaken from a sense of obligation, irrespective of their outcomes. This principle underpins his categorical imperative, which mandates acting according to principles that possess universal applicability.
Step 2: Analyzing the Options.
- 1. Aristotle: Aristotle's ethical framework emphasizes virtue and the cultivation of good character, rather than duty for duty's sake.- 2. Plato: Plato's philosophy centers on justice, the theory of forms, and the ideal state, but does not specifically articulate the concept of duty for duty's sake.- 3. Socrates: Socrates focused on virtue and the examined life, but did not structure his ethical system around duty for duty's sake.- 4. Kant: This option is accurate. Kant advocated the notion that morality is derived from fulfilling one's duty, without regard for consequences.
Step 3: Conclusion. The accurate selection is 4. Kant.
Final Answer: \[ \boxed{\text{The correct answer is 4. Kant.}} \]