When it comes to human achievement, we can all very easily agree that there are no limitations in capability. If we ever come across something that can't be done (as Vinci did), rest assured at some point in time, the ability to do it will come about. Most of Vinci's ideas for inventions were impossible simply for the fact that the tools and parts needed for them to work had not been invented yet, and simply couldn't be made yet. Some might just call this "imaginative"; but remember, they happened.
While it is true to say that human beings have no limitations in what we can achieve, I think it's important to remember while we're strutting down the path of innovation, looking at all of the stuff that we've accomplished despite the odds and obstacles, we need to keep humble -- not to each other, but to nature.
But what do I mean.
There is a vague worldly definition of "natural" and "unnatural". If
you want to argue that the "unnatural" is anything that doesn't occur
automatically in life without interference, then you could argue that
bird nests and beaver dams are "unnatural".
So, if that's the case, then cellphones, TVs, computers, and the lot are all "unnatural".
But I have my own definition for what's "natural". If you look at it in that way, then everything we do that exploits nature itself is still natural. We require nature in order to make all of the things I mentioned above. They require "natural resources".
So what's "unnatural"?
Let me put it this way:
As long as we stay on earth, we have no liberation from gravity. Sure we may have jet packs, planes, helicopters and so on to keep us in the air, but the entire makeup of those things were created around the bindings of gravity. They have to work with gravity already acting on them in order to work at all.
As long as we stay on earth, we have no liberation from the sea. In all our infinite wisdom and architectural ability, we have yet to create extensive civilization in the ocean. Note that our civilization typically ends at the shoreline. Sure we may create piers, but how far do they go before somebody says "okay, this is getting dangerous"?
As long as we stay on earth, we have no liberation from earthly things.
The "unnatural" would be if, in any case, those statements above were to become false. If we could somehow control gravity. Or the ocean. Or the wind.
But, if that is what's unnatural, then I believe that nothing can be unnatural.
Tesla may have moved mountains (you'll find I support liberal Tesla as opposed to conservative Edison), but had Tesla met The Storm face-to-face, would he have challenged it with his harnessed electrical energy, or would he back down and hope that he isn't struck by lightning?
Keep humble only to nature, because remember: Nature is the one thing that we, as humans, have to follow.