Absence of evidence IS evidence of absence

My argument is a simple: Lack of evidence simply means you do not have any evidence to prove something. If there is no evidence, You can"t make a definite claim either way. While I would agree that lack of evidence may point one in the direction of making it reasonable to believe it doesn"t exist, It doesn"t necessarily PROVE it doesn"t exist. Here"s a simple illustration. Consider X. Consider Y. I assert that X equals Y If I have evidence that proves X equals Y, Then I can say with reasonable assurance that X does indeed equal Y. If I do not have evidence to show that X equals Y, What does that mean? Does it mean X does not equal Y? No, It simply means I cannot show (prove, Say definitively, Etc) that X equals Y. X could very well still equal Y, But I just don"t have the capability to prove it. Does the fact that I can"t provide any evidence PROVE that X doesn"t equal Y? No. It just means I can"t provide evidence. Maybe the evidence is there, It just hasn"t been found yet. Point 1 - Your whole argument begins with a false statement. It is NOT a fact that "the absence of evidence is the only way to indicate that something does not exist. " Here is why it's false (or perhaps misleading) A) By stating this, You are already asserting that it is TRUE statement-- that the absence of evidence indicates something doesn't exist. Isn't this what you are trying to prove? You can't say "I'm going to show that X is true", And then start your argument by saying X is true, And ask the opponent to accept that. B) Not only that, You are saying that this is the ONLY way to indicate something doesn't exist. I call this false or misleading because it includes a statement that has not been proven as FACT yet (see A above). Point 2 - refuting your example. Here is your example or analogy Say you were in my house for a visit, And then you went to use the bathroom. When you come back I say "Oh my gosh you just missed it! A huge elephant just walked through here! It left by smashing through the front door and it walked through my yard and onto the street! "You look around and nothing is out of order. There is no mess, The door isn't smashed, No fallen pictures, Nothing is knocked over, And no footprints are on my yard or in my house. That is all evidence that an elephant was never in my house, And I just made it up. Therefore, Absence of evidence is indeed evidence of absence. My refutation: In your scenario you are confusing "existing" with "being present somewhere" A)Your example proves my point. If that scenario happened, First thing I would do is this: I"d look around and say "Hmmmm, There is no evidence an elephant has been here. Does this prove elephants don"t exist? " I"m sure you"d respond "Well, No. This doesn"t prove elephants don"t exist. " And yet, Isn"t this what you are proposing in your argument. B)What if instead of an elephant, It was a fly. I look around and I simply don"t see any evidence a fly was in the room. I then turn to you and say "Flies don"t exist! There is no evidence in here that flies exist! ". I"m sure you"d argue differently. But this is exactly what you are doing when you say "I don"t see any evidence, Therefore it must not exist! ".