Possible

People sometimes use the word "impossible" too lightly. When I consider whether something is possible, I consider two angles first:

1. Is it logically provably impossible?
2. Is it against the laws of physics?

It's rarely either, at least in my line of work. Putting a problem in these terms makes that clear, which is encouraging. It also makes you think from useful angles. For instance: "where is the physical boundary, and how far are we from that?"

Here's another useful way to get someone thinking productively about tough problems. The implicit question in discussions of a project is "is it possible?" This is evaluation: considering whether to accept or reject.

A much better question is "why is it possible?" Asking it like this switches you from evaluation to true creativity, which is scarce. The most fruitful people have both.