The Hawking Reality Scale is a way of measuring how 'real' something is. This scale was not, as it may sound, created by the physicist Stephen Hawking. It was in fact devised by Clifford Pickover, a Research Staff Member at the IBM TJ Watson Research Centre who conceived of it and then attributed it in honour of Hawking. Pickover is also an inventor and the author of countless magazine columns and books about physics, computers, art and philosophy. He invented the Reality Scale primarily as a way of gauging how unreal his science-fiction novels - the 'Neoreality' series - were. The Neoreality novels all feature the 'distortion' or 'fragmentation' of reality - a bit like dreams that get weirder and weirder. Current reality is 0 on the Reality Scale. Each unit on the scale is called a decireal - abbreviated to dR. Each successive 10dRs accounts for a reality one hundred times more distorted than the last - in other words, the unreality increases exponentially with every decireal increase. Here are some rough examples of scenarios that constitute reality fragmentation and their approximate dR ratings:

• Very close to 0dR - Something very strange but possible - eg, Microsoft going out of business.

• 0.3dR - Your neighbour is wearing fingernail polish that blinks from red to orange.¹

• 15dR - A man's pet gerbil suddenly acquires extra bedding material, seemingly from nowhere.

• 60dR - A gerbil knocks on your front door and asks for some extra bedding material. Pickover's novel, Egg Drop Soup claims to be set in a 60dR reality.

• 90dR - Some extra bedding material knocks on your door and asks for a gerbil. Pickover considers that eight hours of 90dR reality can damage your brain, but anything over 85dR could conceivably cause mental damage. At this point you would probably consult a friend to ask if you were going insane or not.

• 110dR - A truck load of cotton wool is deposited through your chimney, sprouts wings and explains its quest to find uncomfortable gerbils. Pickover's novel, Liquid Earth claims to reach this level of reality fragmentation.

• 120dR - You suddenly find that you are in fact a gerbil, and your eyeballs clone themselves and travel down your trachea singing 'Jingle Bells' when it is only August (or is it June?)

• 140dR - Any exposure to this reality would cause immediate mental damage, possibly rendering you unconscious because it is totally incoherent with any of your ordinary experiences.

Pickover's scale could conceivably be used to measure how strange your dreams are, and in the future, we may even use it to gauge how different alien worlds are to our everyday terrestrial reality. It could also be used to measure the experiences of people suffering with schizophrenia, or who claim to have had an out-of-body, near-death or otherwise 'unreal' experience. At the moment, however, none of these uses have become a reality.