You're three years into a relationship, and your friend asks you if you are happy. You open your mouth, and nothing comes out. It's not quite a yes. It's not quite a no. There is an answer that you're reaching for, but you can't find it. According to Plato, 2500 years ago, that feeling is one of the most important questions in philosophy. ‘Meno's paradox’ says that we cannot find the thing that we don't know we are looking for. If you don't know what a good relationship looks like, you can't build it. If you don't know what job you want, you can't look for it. And if you don't know what happiness looks like, you can't walk towards it. The answer works in two steps. The first is to find the prototype. Don't ask, 'Am I happy?' but rather, 'When was the last time I was happy?' On that morning I felt happy, who or what was there? On that afternoon I felt miserable, what was going on? And the second is that we test this prototype against the world. Try it out again for a week and see if the results are the same. But, of course, this isn't just about happiness. This is about any major life decision. It's when you ask if you should stay in a job or not. It's if you ask whether you love this person or not. These are answered by building a rough picture, taking them out into the world, and watching what the world does to them. Don't go looking for the things you don't know you want, but find out what you like, what you value, and what you do want, and build the rest of your life out from that.