Aliens have arrived on Earth. Two of them, of exceedingly strange appearance (floating, glowing orbs of bright light; nothing more) have emerged from a
glistening, spherical spaceship whose only marking is “CTC3” and, hovering about six feet above the ground, speak this aloud to the UN Secretary General and five scientific advisors standing with him in New York City, in crisp English:

“We come in peace to quickly solve your biggest problems (silly wars and use of silly power sources being two of them), and then loop back home before going to yet another primitive planet in need of assistance. We are on a very tight schedule so as to hit three black holes in correct sequence. As an indicator of our coming handiwork, here” — a small book is handed over, along with a datastick — “is the cure for all forms of what you refer to as ‘cancer.’ The material also includes the number that is the \Sigma function applied to input 7, with an accompanying proof of correctness in the system your computational logicians know as ‘Athena.’ Now, so that we can serve you rapidly, please immediately grant us access to every corner of your world, including its cyber dimension. Our renovation should take at most one of your hours, after which we’ll be on our way. We await your rapid response, within one hour max. At the expiration of that period, if you decline, we shall depart immediately, leaving you to your own (primitive) devices. We are of course aware that you have hand-picked the quintet standing with you, so in the interests of efficiency and cleanliness, the one hour of deliberation should be confined to you and them, here, on the spot, in this very room, which is large enough for some side-meetings as needed. Of course, use of your little Internet during deliberation is permissible. The countdown starts … now.”

The science of universal intelligence (SUI) is a field that has arisen in the 21st century out of AI and — especially — AGI. It is concerned with theories providing a rigorous definition of and measurement scheme for intelligence in agents short of, at, and beyond the human level. These agents can be natural or artificial, or a mixture thereof. One such theory, from Marcus Hutter (2005) and Shane Legg (& Hutter) (2007), is their theory universal intelligence; it’s a purely numerical/