Our current drug crisis is a tragedy born of a phony system of classification. For reasons that are little more than accidents of history, we have divided a group of nonfood substances into two categories: items purchasable for supposed pleasure (such as alcohol), and illicit drugs.

Mass extinctions may not threaten distant futures, but they are decidedly unpleasant for species caught up in the throes of their power.

Human consciousness arose but a minute before midnight on the geological clock. Yet we mayflies try to bend an ancient world to our purposes, ignorant perhaps of the messages buried in its long history. Let us hope that we are still in the early morning of our April day.

Any decent writer writes because there's some deep internal need to keep learning.

Life is a copiously branching bush, continually pruned by the grim reaper of extinction, not a ladder of predictable progress.

Transitional forms are generally lacking at the species level, but they are abundant between larger groups.

The world is too complex for subsumption under any general theory of change.