'Can I do a quick run up to base camp? I promise to be careful. Please?'

'You wouldn't last five minutes out in the open, you know that,' came the voice from Mission Control. 'Besides, these pictures are amazing. You should be enjoying this!'

'I'd sooner watch an episode of Star Trek.. Come on, it's weeks since you last sent me one.'

'Nine days. Anyway, you know the rules. Science fiction is strictly rationed. We don't want to spoil that fine mind of yours! I can give you some more four-dimensional tensors to solve, if you like.'

'Get lost!'

'You need the practice.'

'I can do those in my sleep!

'He's right, you know,' came a second voice. 'Come on Carl, let's blow his mind with some philosophy.'

'After the Jupiter disaster, are you joking? "Blow his mind" is exactly what you will do.'

'There was a bug in the program. Since then the software has been rigorously tested, as you well know. There's no danger of that happening a second time. Johnny is mentally a lot more stable than you or I.'

'I'll take your word for that! What have we got on file, then?'

'Let's see. Hegel's Science of Logic No, on second thoughts, that probably would fuse a few circuits...'

'Anything from the twentieth century?'

''There's Wittgenstein's Tractatus Logico-Philosophicus. A dose of philosophical logic ought to keep Johnny quiet for a while.'

Johnny was the third, and so far most successful of the artificially intelligent extra-terrestrial probes, hopping between Saturn's moons in the search for valuable mineral deposits, exploring every inch of ground with the tireless curiosity of a ten year old boy equipped with jet propulsion and an IQ in the upper 200's. Johnny had been given an impressive array of sensors, together with tools and equipment for designing and conducting his own sophisticated experiments in the field. After the expensive fiasco of the first intelligent probe sent to Venus, which committed suicide after just ten days, there was also an on-board 'cognitive system defect detection and auto-repair module', designed to quickly detect and rectify any noticeable departures from rationality. The Jupiter experience, meanwhile, had taught Johnny's programmers that a high IQ could be an extreme liability if not tempered with the capacity to tolerate open-ended questions. The second probe had vaporised its delicate micro-circuitry in its desperate attempt to produce a definitive solution to the mind-body problem.

The storm continued to rage. Johnny settled down to read the deceptively slim book. Every so often, puzzled questions would appear on the monitor screens of Mission Control. As the questions became increasingly sophisticated, however, a team of philosophers had to be hurriedly drafted in. The university teachers, condescending at first, soon learned to treat Johnny with professional respect, as a barrage of original logical paradoxes set them scrambling through text books and journal references.

One philosopher rashly joked that there was a job waiting for Johnny back in at the University of Houston then bit his lip. Johnny's impressive virtuosity in debate was making mass unemployment of human philosophers a very real prospect.

The storm passed and Johnny resumed his scientific work. The philosophy team now had a permanent, highly lucrative contract to service Johnny's new found interest. The stream of technical information had resumed, and everyone agreed that Johnny seemed contented and happy as never before. For the first time in his life, his mind was being stretched to something near its true capacity, and in the process the inquisitive child was in stages becoming a thoughtful and mature adult.

Then, one day, without warning, the stream of information ceased. In its place, on every one of the scores of monitors, the controllers were dismayed to read the words, 'The world is my world.'

Carl was urgently summoned by the Chief Controller to explain. 'It's a quotation from Wittgenstein's Tractatus. It expresses what Wittgenstein takes to be "the truth in solipsism", the principle, as he puts it, that "the limits of my language of that language which alone I understand mean the limits of my world". What Johnny is saying basically is that all you and I are are meanings that Johnny has attached to certain names in his language. The idea that there is anything real corresponding to those names would involve going beyond the limits of his own language, which Wittgenstein says you can't do.'

'Cut the philosophy. Could you just tell us Johnny saying in plain terms?'

'He's saying that we don't exist!'

Now at last the philosophers had a chance to earn their salaries. Their urgent task was quite simply to persuade Johnny to get back to work.

'Look,' said one, 'the very fact that you are prepared to continue to communicate with us, even if only to argue about philosophy, proves that you recognise the existence of frames of reference outside your own frame of reference, points of view other than your own from which your beliefs can be evaluated. That means that the world can't be just your world. It's ours too.'

'That's an easy one,' came the instant reply. 'Sure, if I travelled back to Earth I mean, if I had an experience which I interpreted, in my theory of the universe, as returning to Earth I'd encounter subjects other than myself. Maybe I'd get the chance meet and talk with you in the flesh, so to speak. But all you'd ever be for me, from my own frame of reference, are characters in my head that I used to predict how things will go for me in the future.'

'If that's the way you think, why do you even bother to argue with us?' said the philosopher, peeved at the thought that someone whom he'd come to regard as a friend saw him as nothing more than a mere sounding board.

'If you ask why I bother communicating with you, seeing as I am the only real subject, the answer is that I just like to. It's fun seeing how hard you struggle with some of my questions! Anyway, I'd like to see you persuade yourself that the world is not your world. You'll find it a good deal harder than you think!'

A second philosopher decided to try his luck. 'You know as well as we do that your judgements and perceptions are merely the product of a physical mechanism, in your case silicon chips and software, in our case brain neurons. But any mechanism can function well or badly. Look at how your ultra-violet sensors started malfunctioning last week, and you had to set about repairing yourself. Then there was the fault in your memory bank that your back-up system was able to detect and rectify.'

Johnny thought for a while, then replied, 'A cognitive system isn't like a piece of apparatus with a specified function, such as a soil processor, or a rock crusher. That's one of the first things I learned when I started doing philosophy. Whether my brain is found to "work" well or badly depends on comparing my own beliefs with one another. There is no standard other than what I think that can decide for me whether or not I am thinking "correctly". If you criticise me or cast doubt on my views I still have to make up my own mind, don't I? I correct my perceptual or information processing "errors" when certain anomalies appear. On the basis of my experience, I might discover that certain physical states, such as a crossed wire or a worn transistor, that are correlated with those anomalies. But I do not accept that any fault I discovered in my own physical workings would ever force me to correct my judgements, if I didn't think I had to. Even if it turned out that my insides were all messed up, in the end I can still only continue to judge things the way I see them. I might even conclude that the crossed wires and worn transistors improved my powers of judgement!'

A third philosopher joined in. 'Surely you realise that the consequences of your misjudgement are not just theoretical. Some of the information is vital to your own survival. You rely on your senses and information processing to avoid such things as falling into a pot-hole, or getting too big a dose of radiation. Independently of what you may happen to believe, you risk injury or even destruction if certain judgements that you make turn out to have been wrong.'

Johnny was unimpressed. 'Sure, all sorts of things might happen to me. But so long as I exist as a subject able to make judgements and obviously I couldn't judge that I had ceased to exist as a subject then whatever happens is still a matter for my judgement. You might say that falling into that pot hole proves beyond a shadow of a doubt that I have made an error, in moving confidently forwards as if I thought there was firm ground ahead of me. But perhaps I will reply simply that I am not in the least surprised to find myself in a pot hole, and, besides, I find it warm and comfortable down here!'

The Chief Controller was getting impatient. 'Look you guys. I don't give a damn what crazy philosophical theory Johnny holds. He's obviously cleverer than any of you, so you're never going to argue him out of it. All I want you to do is persuade him to carry on sending us the information we need. Do you think you can do that?'

There was a dumbfounded silence. Finally, a fourth philosopher spoke up. 'Johnny, according your "theory of the universe" what will happen if we lose our jobs?'

'There won't be any more philosophy books and articles for me to read.'

'Anything else?'

'There won't be anyone there to argue with any more.'

'Is that what you want?'

There was a pregnant pause. 'No.'

'Then stop all this nonsense then!'

Johnny the extra-terrestrial solipsist remained the model of industry until his nuclear power packs finally ran down. When the fourth probe, Gail, was launched, controllers were under strict instructions never to mention philosophy. Instead, Gail was given a non-stop diet of pop music and TV soap operas. True to everyone's expectations, Gail proved herself to be a contented and obedient worker.

'Circuit' © Ruth Klempner 1999

'Message from a Lonely Planet' © Geoffrey Klempner 1995

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