Why can't inner classes declare static members?

Question

The Java Tutorial says that since an inner class is associated with an instance of the enclosing class, it (the inner class) cannot define any static members itself.

It\

Answer 1

Because the Java Language Specification says so:

An inner class is a nested class that is not explicitly or implicitly declared static. Inner classes may not declare static initializers (§8.7) or member interfaces. Inner classes may not declare static members, unless they are compile-time constant fields (§15.28).

As for why it was specified that way, I do not know. My guess is that inner classes were designed as small helper classes that should be very limited in complexity.