 A second way one might characterize the autonomy of emergent entities is through realization by base properties that does not depend on any specific realization. Physical realization secures a clear form of dependence on base properties  (section 2.1.2).  But realized functional properties and processes are (or appear to be) consistent with a variety of possible realizer properties (e.g., having a headache, even of a highly specific type, is consistent with different precise neural states, and more general mental state types may be realized more widely still, across biological species and perhaps in alien or artificial minds). They are multiply realizable, dependent on there being some physical property or process or other within a range, without depending on any specific such feature. There are other varieties of realization beyond the functional that might be apt candidates for understanding particular cases of emergent autonomy. For example, emergent properties might be determinables which are determined by different lower-level determinates (Macdonald &amp; Macdonald 1986, 1995 and Yablo 1992); types and/or tokens which are proper parts of lower-level types or tokens (Clapp 2001 and Shoemaker 2000 [2001]); or having strictly fewer degrees of freedom than do their bases (Wilson 2010). These options, which need not be mutually exclusive, are discussed further in  section 3.2.