Food for thought. Speaking of food, it has margins as well. There is a short and specific time frame where meats and vegetables are considered optimal. Stay within the food margins, or buy one of those dehydrators they sell on those infomercials. Life itself has margins.
Philosophers debate their meaning.
Supreme Courts try to determine exactly when they occur. People carry picket signs, brochures, and self-righteous attitudes because they are convinced that they know for sure. Dr. Kervorkian sits in jail because he moved the wrong one. Ask any musician or artist. They'll tell you - it's the segues, the transitions.