Hi, I'm Peter Adamson and you're listening to the History of Philosophy podcast, brought to you with the support of Kings College London and the Leverham Trust, online at

W.W. history of philosophy.net.

Today's episode will be an interview with Richard Serraubji,

who is an emeritus professor of philosophy at Kings and an honorary fellow at

Wolfson College. We'll be talking about Aristotle's physical theories in particular

his views on time and eternity. Hi Richard, thanks for joining me.

Hey Peter. I thought I might start by asking you about Hi Richard

I might start by asking you about time

Aristotle defines time as the measure of motion in respective before and after can you

explain what that means exactly?

Well I think that Aristotle prefers to define time as the number of motion in respect of before and after, but by number he means something special.

He means what's countable.

In full, I think he means, that time is the countable instantaneous stages of emotion.

That would be the first part. Number of motion means countable instantaneous stages of

emotion. What about in respect of before and after?, he means in respect of what's spatially before

and spatially after in the motion.

Just two points. He means number to go into the definition rather than measure because measure

introduces an extra idea. When you are measuring you need evenly spaced instantaneous stages.

So that's a special case of being countable.

But to have time, you have time, whenever there are countable instantaneous stages of emotion, regardless of whether

they're evenly spaced. So though he does also say that time is the measure of motion. I don't agree with those people who think

that that's the actual definition. I think the actual definition is number in the sense

...