I really don't know the probability of a person saying hello to a stranger who said hello to them. It depends on too many factors, like the look & vibe of the stranger, the history of the person being said hello to, etc.
Given a time constraint, I'd agree that I'd be more likely to predict that the girl would reply hello than to predict Deep Blue's next move, but if there were not a time constraint, I think Deep Blue's moves would be almost 100% predictable. The reason being that all that Deep Blue does is calculate, it doesn't consult its feelings before deciding what to do like a human might. It calculates 200 million positions per second to determine what the end result of any sequence of chess moves will be. If you gave a human enough time, I don't see why they couldn't perform the same calculation & come to the same conclusion that Deep Blue would.
Edit:
Reading more about Deep Blue, it sounds like it is not as straightforward as just calculating. There is some wiggle room in there based on the order in which its nodes talk to one another. It won't always play the same move given the same board positioning. Really fascinating! Thanks for engaging politely, it motivated me to investigate this more & I'm glad I did.
I really don't know the probability of a person saying hello to a stranger who said hello to them. It depends on too many factors
I'm not asking for the probability. I'm asking for your probability -- the confidence you have that the event will occur. If you have very little confidence one way or the other, that doesn't mean you assign no probability to it; it means you assign ~50% probability to it.
Everything in life depends on too many factors. If you couldn't make predictions or decisions under uncertainty, then you wouldn't even be able to cross the ...
A stub on a point that's come up recently.
If I owned a paperclip factory, and casually told my foreman to improve efficiency while I'm away, and he planned a takeover of the country, aiming to devote its entire economy to paperclip manufacturing (apart from the armament factories he needed to invade neighbouring countries and steal their iron mines)... then I'd conclude that my foreman was an idiot (or being wilfully idiotic). He obviously had no idea what I meant. And if he misunderstood me so egregiously, he's certainly not a threat: he's unlikely to reason his way out of a paper bag, let alone to any position of power.
If I owned a paperclip factory, and casually programmed my superintelligent AI to improve efficiency while I'm away, and it planned a takeover of the country... then I can't conclude that the AI is an idiot. It is following its programming. Unlike a human that behaved the same way, it probably knows exactly what I meant to program in. It just doesn't care: it follows its programming, not its knowledge about what its programming is "meant" to be (unless we've successfully programmed in "do what I mean", which is basically the whole of the challenge). We can't therefore conclude that it's incompetent, unable to understand human reasoning, or likely to fail.
We can't reason by analogy with humans. When AIs behave like idiot savants with respect to their motivations, we can't deduce that they're idiots.