@freemo why do you assume an intelligent species that we could detect communicates with radio waves? since we don't know how prevalent complex life is, any conclusion like that is B.S., isn't it?
@2ck Because EM waves move at light speed and there is no form of communication equally as useful that would be accessible to most developing species.
How else would you propose they communicate long distance that wouldnt be far beyond the initial levels of science a species would develop?
@freemo whale-like species in a world ocean communicating through low frequency vibrations. planetary network of intelligent plants communicating by RNA-coded messages through their roots.
anyway, maybe there's no need for long distance communication for ET: they all live in a small enough region of their planet that they don't need long-range
@2ck Whale-like species are not intellectually advanced, if they were they wouldnt be communication through low-frequency vibrations alone and would employ EM.
Low frequency ocean communication is far inferior to EM for several reasons.
1) it has extremely low temporal resolution. Therefore can only communicate very small amounts of information. Nothing even approaching reasonable data rates for communication could be achieved
2) it only works when the ocean conditions are just right. Most of the time at any given moment a whale is completely unable to communicate globally using this method. It is only when conditions are just right that global windows open up.
Etcetera.
The other idea of chemical communication through roots would likewise be limited in all likelihood. It would effectively be a chemical mesh network which current theory already tells us can not work in global, public, high speed, communications network due to some fundamental limitations.
As for not needing global communication. Sure that could work for a species. But would be invalid if we are talking about any species capable of interstellar travel, or even travel across their own planet. Which is exactly the type of species we are talking about.
@freemo you never said we're talking interstellar. are you assuming that any other intelligent life would have been observed by us by now?
The main argument of the OP is that life never reaches the point of their evolution to become interstellar, or to give off much in the way of EM we can detect in general, because the time between a species advances enough to both need and utilize EM is shortly before the point a species is advanced enough that it kills itself off as well.
@2ck Thats not really an alternative is it?
"ET occupies a world in which EM radiation never developed"
Not sure what this means but as I see it it can mean one of two things...
1) ET takes places in a universe with different laws of physics that make it so EM is not useful for communication. In which case it wouldn't apply for our universe.
2) The species just never figures out how to use it as a useful form of communication. In which case they are terribly intelligent, at least not at our level yet.
As to your other point "low natural birth rate + lack of interspecies competition + strong cooperative biases" doesnt add up for me either.
1) low natural birth rate does not effect the evolutionary equation for selfishness. As we observe in species lower natural birthrate is coupled with a greater investment in resources per-child, and thus the main evolutionary drive to create species with lower birth rates than others. More resources per child results in greater chance per child of survivability. The overall need of resources for all of a mothers children per-unit-time remains the same in lower birth rate species more or less
2) lack of interspecies competition wouldnt matter either. The drive for selfishness is just as strong, if not more so, out of competition with ones own species. Remember the drive of evolution is **not** to propagate the species, it is to propagate ones own genes at the expense of everyone elses genes, including those in your own species. Therefore intraspecies competition would be as much a drive as interspecies competition. Which is inherent.
3) strong cooperative biases are moot to the argument as that is what the whole discussing is about in the first place so it dodges the question to assume a species could somehow have such biases. Generally evolution does not promote strong cooperative biases outside of a small group (a family or tribe) and does not appear as a quality between members of a whole species except where, as I stated, resources are extremely limited such that a species has reached the carrying capacity for its niche.