Because they no longer have a brain (memory).
But in a mythical world like Journey to the West, souls are very powerful and might be capable of carrying some memories.
Only then would one need to drink 'Meng Po Soup' and such.
Thinking about this.
Zhang Feng feels that 'unlocking the mystery of the soul' is the key to entering the Nascent Soul stage.
Also, according to his high-dimensional theories from over a decade ago, if the Golden Core and Nascent Soul are truly four-dimensional, and Divinity Transformation and Void Comprehension are five-dimensional.
Then indeed, after the soul reaches the Nascent Soul stage, it becomes a 'thoughtless' four-dimensional entity within the body.
Then, during Divinity Transformation, the Nascent Soul's spirit (soul), combined with thoughts (brain thinking), influences the outside world through spiritual matter and the soul, naturally becoming the theoretical five-dimensional being.
