We can't honestly have any practical discussion about the concept of a Great Filter until we get to the point that our observational capability would be suffici

We can't honestly have any practical discussion about the concept of a Great Filter until we get to the point that our observational capability would be sufficient to reliably detect another civilization at a similar level of development to our own within a sufficient size search space: within our own galaxy for instance. Considering that 68% of the universe's energy and 27% of its mass is still basically unaccounted for, it's clear we have a very long way to go before this idea is worth bringing out of the halls of existential philosophy. Let's say for the sake of argument that a civilization exists in our nearest neighbor system, Proxima Centauri. Let's assume that it has developed with a similar impact to their system as humans have had to our own -- radio emissions, a handful of interplanetary and interstellar space probes, nuclear tests, etc. Could we detect them? Everything I have read concludes that we currently could not. The concept of being able to receive interstellar TV transmissions is such a sci-fi trope I don't think very many people consider that it is essentially impossible.