There have always been people who thought we would never fly, never get to the moon, never travel at the speed of sound, never circumnavigate the world in a day or two.
That's not evidence that "they're" wrong this time, but it does suggest we ought to be careful before asserting what's possible and impossible. I doubt that we'll have "machines that think" in my lifetime, nor even in the lifetimes of my children, nor even perhaps in the lives of their children - but one day, I think it will come.
Your problem is in the assumptions you make, both of which seem reasonable, and either or both of which might be false:
1) You assume that programs are scripted and that scripted is the same as deterministic.
2) You assume we are not.
It's far too early to think that we can't ever figure this out. Don't forget that a lot of ideas started with literature. Icarus flew millenia before Orville and Wilbur did, and Jules Verne shot us to the moon almost a century before NASA did.
