To over-simplify it, "The Great Filter" is an attempt to explain the "Fermi Paradox," which asks why we have not detected intelligent life anywhere elsewhere in the universe.  The suggestion is that some point in the evolutionary process is so improbable as to be impossible, a "Great Filter."

The easiest picking for a "Great Filter" is the distance between stars and the physical limits of interstellar travel.  For instance, if a star system is 4 light years from Earth, that is 24,000,000,000,000 miles away.  With our current technology, it would take us 600 million years to travel that far, and that is our closest neighbor.

We may have already passed "The Great Filter." Perhaps the step that has prevented advanced life in other star systems somehow missed us.

But my fear is that we are seeing it now.  Our technology has evolved beyond the average person's ability to understand it.  A population that does not understand math or science just voted for feeble-minded superstitious leaders.  Will we be our own "Great Filter?" If so, are we are only following a well-trodden path?  We shall never know.