The SETI project has not yielded any evidence of alien life

Question: Do aliens exist?
Position‹4 of 4: Detection or contact with an alien life form is not possible
Argument‹2 of 2: The SETI project has not yielded any evidence of alien life

The Search for Extra-Terrestrial Intelligence has been operating for long without giving any evidence

The argument

The argument rests on what a sustained and well-designed search has failed to find. The SETI project looks for alien life by listening to radio waves from space. Its method is one of discrimination: the sky is full of natural emission from stars, galaxies and other astrophysical sources, and the task is to separate that background from any signal that would have to have been generated by an intelligence. A natural source produces radiation with characteristic properties, and a deliberate transmission would differ from it in ways that can be specified in advance and searched for. This is a reasonable way to look, and arguably the way most likely to succeed. Radio waves cross interstellar distances, they are inexpensive to produce for any civilisation capable of producing them at all, and listening requires no journey and no contact, only an instrument pointed at the sky. If detection were possible by any means, this is the means by which it would be expected to happen first. So far the research has not provided any results. No signal has been found that survives the discrimination the method depends on. That absence is informative precisely because the search has run for years, across many targets, using the most favourable technique available. What proponents of this position draw from it is not a conclusion about whether alien life exists but one about reach: a search of this duration returning nothing suggests that detecting a communication is highly unlikely. Because the most promising method has produced no evidence, they hold that detection or contact with an alien life form is not possible.

Premises

[P1]The SETI project searches for alien life by listening for radio signals from space and distinguishing those generated by an intelligence from natural emissions like stars and galaxies. [P2] Decades of this research have yielded no results, suggesting that detecting such a communication is highly unlikely. [C] Therefore SETI's lack of any evidence indicates that detection or contact with an alien life form is not possible.

Counter-arguments

Looking for radio communication might be a limiting factor since it assumes aliens communicate in a method similar to ours. Charles Stuart Bowyer states that method might be ineffective: it also requires that communication is directed towards earth or Solar System with a high-energy beam. Hearing a radio leakage similar to our radio and TV transmission is extremely unlikely.

Rejecting the premises

The "Fermi paradox" states that Earth should have already been visited by alien or their probes.