Why is it so often that the best people are stuck in the middle and the people who are running things — the leaders — are the mediocrities? Because excellence isn't usually what gets you up the greasy pole. What gets you up is a talent for manoeuvring. Kissing up to the people above you, kicking down to the people below you.

We have a crisis of leadership in America because our overwhelming power and wealth, earned under earlier generations of leaders, made us complacent, and for too long we have been training leaders who only know how to keep the routine going.

Thinking means concentrating on one thing long enough to develop an idea about it. Not learning other people's ideas, or memorising a body of information, however much those may sometimes be useful. Developing your own ideas. In short, thinking for yourself. You simply cannot do that in bursts of 20 seconds at a time, constantly interrupted by Facebook messages or Twitter tweets, or fiddling with your iPod, or watching something on YouTube.

I find for myself that my first thought is never my best thought. My first thought is always someone else's; it's always what I've already hard about the subject, always the conventional wisdom.

It seems to me that Facebook and Twitter and YouTube — and just so you don't think this is a generational thing, TV and radio and magazines and even newspapers, too — are all ultimately just an elaborate excuse to run away from yourself. To avoid the difficult and troubling questions that being human throws in your way.

Here's the other problem with Facebook and Twitter and even The New York Times. When you expose yourself to those things, especially in the constant way that people do now — older people as well as younger people — you are continuously bombarding yourself with a stream of other people's thoughts. You are marinating yourself in the conventional wisdom. In other people's reality: for others, not for yourself. You are creating a cacophony in which it is impossible to hear your own voice, whether it's yourself you're thinking about or anything else.

Once the situation is upon you, it's too late. You have to be prepared in advance. You need to know, already, who you are and what you believe.