Cup your hands together and peer down between your palms.

What is between them?

One answer is “air”. But we think of air as composed of separate molecules, like isolated islands. What lies between the molecules?

Nothing?

The distances between the molecules differ. Could there be more “nothing” between some, and less “nothing” between others? Could nothing really exist?

The empty space does seem to be nothing. It is tasteless, colourless and weightless. It does not move, and the gentlest breeze can pass through it without resistance.

This is our first question. What is between your cupped palms? Is it space, a vacuum, a place? Is it there at all? Is it something or nothing?

Now pause silently for a moment until you can feel the blood pulsing through your hands. Time is flowing. Your brain is sensitive to the physical passage of time and as each second or so passes it rouses itself and decides to stimulate your heartbeat, sending blood coursing down through your palms.

Does time flow invisibly through the space between your palms, as blood flows through your fingers or as a river flows past it banks? Can you feel time flowing there? Is that the right metaphor?

Does time flow more slowly and more quickly, or at a steady rate? If steady, then steady compared to what? Does it flow at a speed of one hour per … hour?

If no body moves through a space does time still flow there? Can time proceed without change? This is our second question.