While many scientists have attempted to categorize dolls (even if our research goes un-recognized by the greater scientific community), one must always recognize that there are more to dolls than meets the eyes.
Some researchers theorize that all dolls result from parental trauma. But that is simply presumptuous. Others believe they Came To Exist Wrong. But can you look into a doll's eyes and really say its not a beautiful creature of our world?
In my understanding, it is key to ground all doll-knowledge that Dolls exist as-is. They are true dolls, despite our understanding, despite the patterns, their commonalities, or lack there of. Some dolls of have dolltism. Some are made of wood, while others are plush. Certain dolls are animated by magic beyond our understanding! And others are from clockwork and could be theoretically be deconstructed and reconstructed. But please do not deconstruct the dolls!
Others find this variety and resilience to understanding as frustrating. I, however, find the variety to be fascinating. Doll science is truly humbling.