> You can't even say if one human surpassed other human in intelligence, how are you gonna measure machine?
It's not because something is difficult to measure that it does not exist(1). Even if you don't believe in IQ tests, you gotta admit that those people Google just hired are more intelligent than the average Joe. They sure are more intelligent than me anyway. Probably more intelligent than you as well.
In the same way, the idea that one day a machine could be more intelligent than any human being would be very real the day a machine will write scientific papers, program its own code, design high-tech devices, win a Nobel price and stuff like that.
This machine would be more intelligent than Demis Hassabis (the founder of DeepMind) for exactly the same reasons that I can say that Demis Hassabis is more intelligent than me: he does more intelligent things.
1: for example, the famous conundrum "how long is the coast of Britain?" does not suggest that Britain has no coast.