Eh... read up on the literature. Pay special attention to studies done by the British Interplanetary Society and the Advanced Automation in Space NASA workshop in the 80's, not to mention all the work done by early space advocates, some published, some not.
We can say with some confidence that we know how to do something even if it hasn't yet been reduced to practice or yet practially demonstrated. 19th century thinkers showed how rockets could in principle be built to enable human exploration of space. And they were right, pretty much on every point -- we still use and cite their work today.
We have done enough research on automated exploration and kinematic self-replicating machines* to say that it is definitively possible (life being an example), and within our reach if we had pockets and conviction deep enough to create it.
We can say with some confidence that we know how to do something even if it hasn't yet been reduced to practice or yet practially demonstrated.
Right, I'm objecting to the claim that
pockets and conviction deep enough to create it.
are included by definition when we say "general intelligence". (That, or I'm totally misunderstanding you.)
An Article on Motherboard reports about Alien Minds by Susan Schneider who claiThe Dominant Life Form In the Cosmos Is Probably Superintelligent Robots. The article is crosslinked to other posts about superintelligence and at the end discusses the question why these alien robots leave us along. The arguments puts forth on this don't convince me though.