>This still doesn't explain why a civilization with interstellar travel technology would ever want to attack another civilization in the first place. What is to

>This still doesn't explain why a civilization with interstellar travel technology would ever want to attack another civilization in the first place. What is to be gained? Safety, security. These sorts of arguments are not about access to resources, they are about removing as many existential threats as possible. Fewer civilizations --> fewer risks of nutjob firing a light speed weapon which makes the star which you live around go nova. Stross writes about a Nicoll-Dyson Beam: >A Nicoll-Dyson beam is what you get when the entire emitted energy of a star is used to pump a myriad of high powered lasers, all pointing in the same direction. You could use it to boost a light sail with a large payload up to a very significant fraction of light-speed in a short time ... and you could use it to vapourize an Earth-mass planet in under an hour, at a range of hundreds of light years. [0] A civilization which can build a Nicoll-Dyson Beam should be fairly concerned that others may also have this capability. [0]: http://www.antipope.org/charlie/blog-static/2015/04/on-the-great-filter-existentia.html http://www.antipope.org/charlie/blog-static/2015/04/on-the-g...