The philosopher is above all one who believes that by understanding the world, by understanding ourselves and others as far our intelligence permits, we shall succeed in overcoming fear, through clear-sightedness rather than blind faith.
Greek philosophers looked upon the past and the future as the primary evils weighing upon human life, and as the source of all the anxieties which blight the present. The present moment is the only dimension of existence worth inhabiting, because it is the only one available to us. The past is no longer and the future has yet to come, they liked to remind us; yet we live virtually all of our lives somewhere between memories and aspirations, nostalgia and expectation. We imagine we would be much happier with new shoes, a faster computer, a bigger house, more exotic holidays, different friends … But by regretting the past or guessing the future, we end up missing the only life worth living: the one which proceeds from the here and now and deserves to be savoured.
A Brief History of Thought: A Philosophical Guide to Living by Luc Ferry