von Neumann probe

Why would somebody build von Neumann probe

Why would somebody build aggressive von Neumann probe

Are technological civilizations necessarily peaceful?

"Biologist Michael Archer said that any creature we contact will also have had to claw its way up the evolutionary ladder and will be every bit as nasty as we are. It will likely be an extremely adaptable, extremely aggressive super-predator. Physicist George Baldwin predicted that any effort to communicate with extraterrestrials is fraught with grave danger, as they will show innate contempt for human beings. Robert Rood warned that the civilization that blurts out its existence on interstellar beacons at the first opportunity might be like some early hominid descending from the trees and calling "here kitty" to a saber-toothed tiger."
http://sentientdevelopments.blogspot.com/2005/02/is-active-seti-imperiling-humanity.html

We were near to become rogue civilization (Third Reich, Soviet Union)

Why would there be hostile self-replicating probes out there?

Greediness

There might be an extremely greedy civilization out there, wanting lebensraum or raw materials for megalomaniac structures.

Attack is the best defence -attitude

They are sent by a civilization whose motto is "attack is the best defence". If they manage to destroy every other race in nearby galaxies, they can be sure no other civilization is going to pose a threat to them. While this sounds unnaturally cruel attitude to our human ears, I must stress we really don't know how much possible other creatures in the Universe resemble us.

Religious fanatism

An aggressive von Neumann probe could be sent by a religiously fanatical civilization. There could be a religion somewhere in the universe that demands endless amout of sacrifices. Sacrifices for gods are seldom among modern human societies but we can't know if the situation is same everywhere. What could be greater sacrifice than wiping out life in entire universe?

Also there could be a religion that demands every sentient being in the universe must convert to it. So in this case von Neumann probes would act as a missionaries. First they announce their demand to encountered civilization to abandon their old religions and convert to one brought by probe. If the demand is not fullfilled a probe would then use it's weaponry.

Also religious sacrifices are possible, as they are common on Earth.

Friendly probe evolves to aggressive

In this scenario a civilization has launched von Neumann probe with good intentions. For example it could be meant for scientific exploration. However, something goes wrong and a probe that was meant to be peaceful starts to act aggressively - for example starting to consume habitated planets. I can imagine at least three reasons for this:

• Major software bug
• Each generation of probes are slightly different than previous because of inaccuraties and flaws in manufacturing process. After millions of generations probes have undergone an evolution process (just like biological life) that might have changed their behavior significantly.
• Artificial intelligence of a probe is too intelligent - so intelligent that it realises it doesn't have to do what it was programmed to.

Artificial intelligence gone bad

Let us assume it is possible to build a self-aware computer - after all, a human mind and computers work under same laws of nature. Maybe many other civilizations have already build them. In science fiction it is well known scenario that super-intelligent machine turns against it creators. This might really happen if this kind of machine would be intelligent enought and have it's own will. Of course it should have some physical means to subdue it's masters, for example army of "humanoid robots". After securing it's power, artificial intelligence might start to build von Neumann probes. If you believe no living thing would be ruthless enough to do things I described earlier on this page maybe you believe an AI could.

Notice that even a single country within a civilization (or maybe even one technologically magnificent individual creature) could launch VNP.

Why would somebody build defensive von Neumann probe

Civilization that has witnessed attack of vnp remotely

This could have happened most likely in situation where a civilization has received an distress signal from another civilization; an interplanetary sos message, if you will, that also included facts about nature of attack. Maybe this kind of attack could also be seen through advanced telescope.

Civilization thas has been attacked by vnp but survived

This is a case where aggressive vnps - or maybe only one vnp - has attacked another civilization. However, victim has managed to repel them and immediately after that started a vigorous campaign to protect themself in the future.

Civilization that suspects it could have launched an aggressive vnp by itself, on right circumstances

If history of your planet has been struggle between selfishness and sharing, revenge and forgiveness, war and peace, then it is easier to assume that there are other planets that has experienced same kind struggles. And we can pretty safely assume that these kind of struggles do ot end the same way.

Peaceful but cautious civilization that has speculated on possible threat by VNPs and decided to take no risk

Conclusion

If there are several technological civilizations in our galaxy, there will be at least one common interest: making sure there are no aggressive VNPs

In fact, if there is such thing than exopolitics I think this issue is clearly above any other. Because of the huge distances of space, these politics are (at least mostly) not possible to arrange with radio or similar communication device. It has to be arranged with von Neumann probes that are acting as "ambassadors". Just like on Earth, every party has told their ambassador which principles to follow. However they are also same time the military of those civilizations.