Step 1: Understanding Occasionalism.
Occasionalism posits that God's intervention explains causal relations between material events. Under this doctrine, God is the ultimate cause of all occurrences. Malebranche is the philosopher most associated with occasionalism, though Leibniz integrated aspects of it into his philosophy, particularly concerning the mind-body relationship.
Step 2: Analyzing the Options.
- 1. Spinoza: Spinoza, a pantheist, did not endorse occasionalism. He viewed the universe as a singular substance. - 2. Leibniz: This option is accurate. Leibniz incorporated elements of occasionalism into his metaphysics, particularly in his theories on soul-body interaction. - 3. Hume: Hume exhibited skepticism regarding causality and did not subscribe to occasionalism, favoring empirical and psychological explanations. - 4. Kant: Kant also rejected occasionalism, focusing instead on epistemology and metaphysics rather than God-mediated causal relations.
Step 3: Conclusion. The correct identification is 2. Leibniz.
Final Answer: \[ \boxed{\text{The correct answer is 2. Leibniz.}} \]