Can babies self soothe?

The term "self-soothe" was not intended to be used as it is used today. It was made up by a researcher called Thomas Anders in the 1970's. He used the term to describe whether a baby woke up and signaled between sleep cycles or whether they "self-soothed" between sleep cycles. 

In his research he put babies into either or category (self soothers or signalers) and this leads to discussions around how much the temperament of our infants impact sleep for that child and the sleep experience for parents. 

Today self soothe often gets used incorrectly, or maybe it has morphed into meaning something different completely? Today when it is used, it typically means that a baby can "soothe themselves" and in sleep terms means that a baby can "self soothe themselves to sleep". This implies the baby has the skillset and brain power required to get themselves from a dysregulated central nervous system state to a regulated central nervous system state. As you can see the original term was not meant to indicate that the baby can navigate the skill of self soothing, it originally was used to indicate which babies could, and which babies couldn't which was based on their temperament, genetics, personality, environment and much more.  

From a brain perspective:

In order to be able to self soothe, a human needs to be able to self regulate. Self regulation is a skill that requires prefrontal cortex (a part of the brain) maturity. The pre frontal cortex doesn't really start functioning until age of 3 years old (does a lot of developing between 0-2yo), and doesn't fully mature until 25ish years of age. 

The ability to self regulate comes from years of being supported via co-regulation and building the brain pathways to be able to do it yourself. As a grown ass adult, sometimes I still need some co regulation in the form of a chat or cuddle from a loved one.  

But my baby self settles, I am confused:

That is great, but babies that "self soothe" aren't technically "self settling", they are just drifting off to sleep easily because their needs have been met and they have a genetic predisposition, a personality and a temperament that allows them to do that by themselves. They literally don't have the brain power yet to be able to self soothe as I have explained above in the brain development paragraph.

In summary so far:

Babies are often either self soothers or signalers from a temperament perspective. Babies can't be taught to self regulate or "self soothe" because it isn't possible from a brain perspective. 

Click part 2 to read below, a spicey take on the answer to:

Q. If the above is true, how come my baby didn't self-soothe, but then they do?