We humans look rather different from a tree. Without a doubt we perceive the world differently than a tree does. But down deep, at the molecular heart of life, the trees and we are essentially identical.

One of the great commandments of science is: 'Mistrust arguments from authority.'

If we can't think for ourselves, if we're unwilling to question authority, then we're just putty in the hands of those in power. But if the citizens are educated and form their own opinions, then those in power work for us. In every country, we should be teaching our children the scientific method and the reasons for a Bill of Rights. With it comes a certain decency, humility and community spirit. In the demon-haunted world that we inhabit by virtue of being human, this may be all that stands between us and the enveloping darkness.

Imagine we could accelerate continuously at 1 g-what we're comfortable with on good old terra firma-to the midpoint of our voyage, and decelerate continuously at 1 g until we arrive at our destination. It would take a day to get to Mars, a week and a half to Pluto, a year to the Oort Cloud, and a few years to the nearest stars.

The Bill of Rights decoupled religion from the state, in part because so many religions were steeped in an absolutist frame of mind - each convinced that it alone had a monopoly on the truth and therefore eager for the state to impose this truth on others.

And you are made of a hundred trillion cells. We are, each of us, a multitude.

But down deep, at the molecular heart of life we're essentially identical to trees.