Intellectual Exploration as Geographical Exploration

My own field of physics is passing today through a phase of exuberant freedom, a phase of passionate prodigality. Sometimes as I listen to the conversation of my young colleagues at Princeton, I feel as if I am lost in a rain forest, with insects and birds and flowers growing all around me in intricate profusion, growing too abundantly for my sixty-year-old brain to comprehend. But the young people are at home in the rain forest and walk confidently along trails which to me are almost invisib...

 There Are Many Types of Islands

IMAGINE a world without islands. Biologists often use the word 'island' to mean something other than just a piece of land surrounded by water. From the point of view of a freshwater fish, a lake is an island: an island of habitable water surrounded by inhospitable land. From the point of view of an Alpine beetle, incapable of flourishing below a certain altitude, each high peak is an island, with almost impassable valleys between. There are tiny nematode worms (related to the elegant Caenorh...