There is so little to work with there that it is hard to say what your real problem but to answer the specific question cited in the post...
what is the function of view:'create' when i call from rest?
The view attribute there is saying that if HTML is being rendered, render the 'create' view.
The JSON you show there suggests that humanInstance is probably an instance of the learn.Human class, that class defines a property named "name" and the instance was validated while the value of the "name" property was null. It isn't clear from the snippet you showed if humanInstance is a command object or if you created the instance yourself and what data was used to populate the instance. It is impossible to say without seeing more code but one thing that might have happened is maybe humanInstance is a command object and the request parameters or request body did not contain a value for the "name" property.