Hacker News Reader

Comment by causi | Hacker News Reader

This is full of ridiculous assumptions. Probably the worst one is the idea that a sapient species that's capable of colonizing space and maintains that ability and attitude for such a long term that other sapient species can arise won't colonize every available star before any other species can do so. Thousands of species occupying separate yet touching volumes of space is mind-bogglingly unlikely.

View on HN

This is too simplistic a critique. One species colonizing everything is perfectly compatible with the model in the broad. The complication is that we ourselves exist, are not colonized, and can look out into space and don't see any alien activity. Hanson starts from this anthropic fact and tries to reason about what we might be expected to see if a) there are "grabby" species out there, and b) we're early enough to witness the land grab. I have problems with the details of the model, but I think it's both a fruitful and interesting attempt to think about things.

Reward-seeking intelligences might have innate features which prevent exponential expansion though and instead result in expansion-contraction loop. For example, for every new colony, the probability that any single colony will begin a civil war may increase. Or the probability that a supervirus will be manifested somewhere and then spread along the galactic population of that species. Basically, if the species are uniform in some manner, the more colonies they have the larger the probability that some colony will spawn an event which utilizes their uniformity to spread and destroy most of the galactic population of that species.

Obviously it's not a guarantee, but I believe it is a viable theory as to why the world described in the article may be possible.

I don’t think that matters much for the distances we talk about. Any such disruption — even if it’s a new philosophy or religion that makes the colonies stop spreading — would only travel at the speed of light, which means that it would take a long time to reach the frontier of a civilization that expands at nearly light speed.

I think that’s attacking the conclusion, not the assumptions. Have you put numbers on what you consider “mind-bogglingly unlikely” and done the math on that, given the distances involved?

The authors supposedly have, and I’m no expert, but I don’t find the argument completely ridiculous. The universe isn’t that old compared to its size; I think it’s plausible for two unlikely events to have happened without their causal cones having intersected yet.

Reply on news.ycombinator.com