Society must demand that you comport yourself within a framework of rules. Once those rules break, society breaks down.

Stress doesn't come from what's going on in your life. It comes from your thoughts about what's going on in your life.

We can only solve our ecological problems by linking ecology and economy. If we can create the right economic environment, change will happen. If it's more profitable to be efficient than wasteful, we will be efficient.

Forgetfulness of the past and the consequences such forgetfulness potentially produces. Extreme nationalism prevents nations from cooperating with other nations.

There is a lot of misunderstanding about demography and one of the biggest misunderstandings is that it's destiny. If it's destiny, it is not that interesting to study, but it's not destiny.