From Straits Times:

…each time I attended a philosophy class, I would feel sparks going off, metaphorically speaking, in my brain. As a result, I did something impractical. I asked NUS for permission to repeat my second year so that I could major only in philosophy and drop economics and sociology. Fortunately, NUS agreed.

Note: Professor Mahbubani is currently Professor in the Practice of Public Policy and Dean of the Lee Kuan Yew School of Public Policy, National University of Singapore. He received a First Class Honours degree in Philosophy from the University of Singapore (now National University of Singapore) in 1971. You can read more about him here as well.