 Despite the fact that aspects of the concept of decisional capacity remain unspecified and undeveloped, it is possible to identify some shared elements that all or almost all theorists agree must be part of the picture. Four sub-capacities are most prominent. These are (1) Choice, (2) Understanding, (3) Appreciation, and (4) Reasoning. Some theorists have also suggested the need for something like (5) Value or Ability to Value (discussed in  §6.1)  and still others have posited the need for (6) Authenticity (also discussed in  §6.1).  Below is a presentation of the most basic and agreed upon elements and an explanation of how these have come to be understood in practice.