Free Willy.
Explanation: This joke is a pun based on the famous 1993 movie Free Willy, about a whale named Willy who is freed from captivity. The phrase “rejects deterministic philosophy” refers to the philosophical concept of determinism, which suggests that all events, including human actions, are determined by previously existing causes and that free will does not exist. By rejecting determinism, the whale is metaphorically embracing free will. The punchline cleverly combines the idea of “free will” with the name “Willy,” making the whale both free and embracing the concept of free will.