True philosophy is that which renders us to ourselves, and all others who surround us, better, and at the same time more content, more patient, more calm and more ready for all decent and pure enjoyment.

A way of thinking is worth having if it improves how you live with people and how you bear an ordinary day. That is a demanding test, and a great deal of impressive theory fails it, leaving its holder cleverer, angrier and no easier to live with. The genuine article shows up as patience, steadiness and a greater capacity for plain enjoyment, not as a better argument.

Apply the test to whatever ideas you have taken up lately. Ask the people around you whether you have become easier or harder to be with since, and take their answer as the score.