10/05/2015 19:04 BST | Updated 10/05/2016 06:59 BST

Fantasy and Reality - Where Do You Draw the Line?

I quoted Gustave Flaubert at the beginning of a novel once, 'There is no truth, only perception.' and it's a statement I find myself thinking about a lot when I look at the world. We all have our own 'truths'; the way we see things, the reality we create for ourselves, how we perceive others. In many ways we all live in a reality of fantasy. I walk into a room a moment after someone else, or a moment before and I see a different angle on a situation. No single experience is ever the same for two people. The people we think we know, we never truly know. Even ourselves. The person I think I am is very different from the person others might think I am. Who's to say which is the 'real' one? Are they all real, or are some simply presentations of me? Fantasies of me? I'm told fields are green and so I call the colour I see green, but I have no idea if it's the same colour green that you see. Of course you could go mad if you think about all that too much so we create a solidity of 'accepted reality' where in fact the only true reality for anyone is what's inside the small world of their own head.

But I'm not an intellectual, or a philosopher, I'm just a storyteller. And of course, within that miniature universe of our own brain existence, lies our individual and unique imaginations. Does imagination inform reality? Of course. Religion sprang from man's imagination. Although not religious myself, I'm not actually dismissing the notion of a 'God' here, but the creation of various doctrines for the control of the population definitely came from the imaginations of man. The Bible is a story collection essentially and has become 'reality' in the lives of millions across the world. Some take it as a literal text, others, like me, see it entirely as a fantasy. It exists as both depending on your perception. Look at L. Ron Hubbard, who made something up, and now people with too much money and too much ego and a very distinct fantasy of reality worship at his altar of aliens. It's all really rather brilliant really, isn't it, in a funny kind of way?

I'm stating nothing new when I say that imagination is the most powerful tool humankind has. Imagination has put man on the moon. The 'fantasists', science fiction writers and film-makers did it way earlier than the 'realist' scientists, but one certainly fed into the other. The 'fantasist' says 'imagine if we could make this happen?' and the scientist water that seed of existing purely in imagination until it bloomed into physical reality. We explore societies through fiction. We explore the nature of existence through fiction. We learn tolerance through fiction - through good fiction at any rate. Even hard science is bound up in fantasy. Just try talking to an astrophysicist for a few minutes - to be fair a few minutes is all I can manage before my tiny brain burns up - and so much of what they 'know' of space is a calculated assumption. It's party why I gave up physics at school as soon as I could. My imagination doesn't work that way. So many things that can't be proved being used in calculations. Story told in scientific formula almost. Yes, the imagination is a wonderful thing. The best thing. Without imagination the human race would have died out thousands of years ago.

At the 'HowTheLightGetsIn' Festival in Hay-on-Wye at the end of May, the theme is Fantasy and Reality and I'll be taking part in two panels, with thankfully, far cleverer and more erudite people than me. My basic stance however, will come from that Flaubert quote in that for me, there really is no difference between the two. It's all just a matter of perception.

That, or of course, the possibility that maybe I just took too much acid during the university years ;-)

Sarah will be speaking at HowTheLightGetsIn, the world's largest philosophy and music festival, running from 21st May - 31st May in association with The Huffington Post UK.