> A "self-replicating probe" is either so weak in capability that it would hardly amount to colonization, or so strong in capability that it would amount to a rival life form.
Why do you assume that? There are plenty of self-replicating machines on earth that have been extremely successful at colonizing their environment, but we would not typically view them as "rival life forms".
> What functionality would you build into such a probe and by what means would you prevent a "boomerang" effect wherein it comes back and causes problems in the home system?
The simplest method would be to have them accept any order signed by a standard public key. I'm not sure why people tend to assume that a self-replicating machine cannot be controlled. There are plenty of self-replicating programs that are controlled very effectively.
> Additionally, if all you are talking about building is a device that would, encountering our solar system, take up residence in orbit, take pictures, and report "back" - how do you know there aren't already several of them present?
Because if have been many intelligent species in our galaxy over the past billion years, it seems unlikely that all would be careful to remain undetected. Certainly our species has little interest in hiding its activities.
> Colonization, as opposed to mere migration, was pretty much always, more or less by definition, for resource extraction.
Plenty of species on Earth colonize new environments without bothering to send resources back to their origins. And there have been plenty of human colonizations not linked to a controlling empire, especially when we were just hunter-gathers.
Why do you assume that? There are plenty of self-replicating machines on earth that have been extremely successful at colonizing their environment, but we would not typically view them as "rival life forms".
> What functionality would you build into such a probe and by what means would you prevent a "boomerang" effect wherein it comes back and causes problems in the home system?
The simplest method would be to have them accept any order signed by a standard public key. I'm not sure why people tend to assume that a self-replicating machine cannot be controlled. There are plenty of self-replicating programs that are controlled very effectively.
> Additionally, if all you are talking about building is a device that would, encountering our solar system, take up residence in orbit, take pictures, and report "back" - how do you know there aren't already several of them present?
Because if have been many intelligent species in our galaxy over the past billion years, it seems unlikely that all would be careful to remain undetected. Certainly our species has little interest in hiding its activities.
> Colonization, as opposed to mere migration, was pretty much always, more or less by definition, for resource extraction.
Plenty of species on Earth colonize new environments without bothering to send resources back to their origins. And there have been plenty of human colonizations not linked to a controlling empire, especially when we were just hunter-gathers.