The essays presented here are speculative and informal—never the last word on their subjects but always only the first. In contrast to the book, I have not settled on their details and do not stand solidly behind them.
Think of them as lecture notes. They are designed to trigger further thoughts in you if you read them, including of course thoughts about where I have got things wrong, in either subtle or even obvious ways.
They are offered on the theory that there should be a space for looser and more speculative writing and thinking than a formal book allows. A person who never misses a flight spends too much time waiting in airports. Similarly, a person who never writes something mistaken captures and conveys too little truth.
These essays are offered in this spirit. Needless to say, they are therefore also offered without warranty, and only for whatever they are worth.