I don’t know if I can do an example in a common enough syntax to make sense. However, the general/basic example for higher kinded types is usually a Collection<

I don’t know if I can do an example in a common enough syntax to make sense. However, the general/basic example for higher kinded types is usually a Collection<T> vs a List<T>. The List take some type T (i.e. int, float, char) and is a list of ‘objects’ of that type. Every ‘object in the list is an int. A Collection<T> is a collection of some type <T<T2>> (i.e. list<T>, option<U>, vector<V>). This allows for the collection to be composed of ‘objects’ whose types are each some List<T> where each objects T can be different. So a Collection<List<T>> could be a list of [List<int>, List<float>, List<char>]. I think the jargony statement is that higher kinded types allow for a type to abstract over types which take another type as a constructor. From my perspective the rationale for higher kinded type is usually the drive/goal of having as high a ceiling for abstraction as possible and create ‘reusable’ and generic code over and above what is available without higher kinded types.