What does it mean to say that a model is "unidentifiable"?

[hhau]

Hello! This topic comes up quite regularly. The following posts and links seem relevant:

• Blog post: Identifying non-identifiability
• Trouble with Gaussian Mixture Model
• Identifiability of Gaussian mixture mode

and the ever relevant:

• https://betanalpha.github.io/assets/case_studies/identifying_mixture_models.html