Peer pressure is the great influencer in academic philosophy. That most academic philosophers are influenced by other academics, especially those who are members of their own peer group, is an inference that you can draw from their writings. The club of leftist and liberal academic philosophers is probably the biggest power center—they dictate the philosophical agenda of much of the academic community. Even the libertarians and conservatives prefer to toe the line taken by their leftist and liberal colleagues. I believe that there is much more diversity of opinion and wisdom in the masses than there is in the academic philosophers.