Original: Discussions with fellow Nobel prize winners Amartya Sen and Kenneth Arrow, and especially the influence of the philosophy of John Rawls, whom he met during the year at the Center, led Phelps to undertake some research outside macroeconomics.
Simplified: Meeting with Nobel prize winners Amartya Sen and Kenneth Arrow, and reading the work of John Rawls, whom he met during that year, gave Professor Phelps an interest to research outside of macroeconomics.