I am not sure you realise how seriously flawed a philosophy is when it says unicorns exist.
This one statement in-itself has implications to so many things. I have randomly asked a number of people “do unicorns exist”. They all say no and then invariably ask me why do I ask.
Trump could well say “unicorns exist” to his supporters and they would absolutely believe him.
Now I know this is not your intention and that you take this position seriously but I guarantee you if you ask someone (apart from Harman perhaps) he or she will respond in a way very similar to how I just did.
My question to you is “do unicorns exist”?