I define it as superstitious or religious nonsense. I define it as ignorance. Nothing about the working of the human mind requires something else to exist to make it work.

People who believe that a soul or spirit is required for the human mind to work are religious (or otherwise superstitious) people advancing claims because they want to believe, normally because they were raised in a superstitious society.

But that's not how the world works. Things aren't true because people want them to be true. Plus, religion has never presented any sort of valid way to actually know things.

Most of the history of humanity and of our search for knowledge centers around crushing religious opposition to intellectual investigation and discourse.

The enemy of true discourse is superstition.