What proof do we have of AGI being possible at all?

So, everyone is saying "AGI is just around the corner!" I've come from psychology - a very controversial field which has a massive scientific problem - being "everyone rides its own wave". Only external scientific terminology is universal and agreed upon, with relatively few other things being widely accepted - there are a lot of different "psychologies" so to speak. So, I feel there's the same thing going on with AGI. Everyone "makes AGI", but no official widely agreed description of it exists. No one even publishes to what are their goals for.