Love is free; to promise for ever to love the same woman is not less absurd than to promise to believe the same creed.

Natural experiments are a powerful tool for understanding causal relationships in the real world.

In the energy sector, we must balance progress with responsibility - our actions today shape tomorrow's world.

The capacity of the human mind for formulating and solving complex problems is very small compared with the size of the problems whose solution is required for objectively rational behavior in the real world.

爱就是冒着受伤的风险，而不爱则是保证了一生的虚度。