1. INTRODUCTION: HEREDITY vs. ENVIRONMENT

Recent attempts to unify certain classes of active galactic nuclei (AGN) using orientation and environmental effects have been rather successful (Orr & Browne 1982, Antonucci & Miller 1985, Barthel 1989, Urry & Padovani 1995, Wall & Jackson 1999). However, it is widely recognized that intrinsic properties of the accreting black hole systems that are thought to power AGN must also play a role in determining the appearance of these objects. While there is still much to be learned, we now know enough about accretion onto black holes and about the production of jets to begin to develop grand schemes that attempt to unify most classes of these objects.

In accretion and jet production theory the principal parameters determining the appearance and behavior of the system are the black hole mass M_H, the mass accretion rate , and the black hole angular momentum J, expressed in dimensionless form as m₉ M_H / 10⁹ M (where M represents one solar mass), / _Edd (where _Edd = 4 G M_H / _es c = 22 M yr^-1 m₉ is the accretion rate that produces one Eddington luminosity for an efficiency = 0.1 and electron scattering opacity _es), and j J / J_max (where J_max = G M_H² / c is the angular momentum of a maximal Kerr black hole). For most AGN and quasar models typical ranges of the parameters are 10^-3 < m₉ < 10, 10^-5 < < 1, and 0 < j < 1. While all parameters will affect the properties of an AGN to a certain extent, the purpose here is to identify the principal observable effects of each.

The unification through intrinsic effects discussed here is not meant to replace that which has been accomplished already through extrinsic considerations. Rather, the accreting black hole system should be considered as providing the basic parent ensemble of AGN in which orientation and environmental effects can take place. Pursuant to the anthropomorphological theme of this conference, this paper will deal with the ``psychology'' of AGN: some traits are inherited from birth (i.e., from the accreting system) and some are a product of the source's environment. Considerations of both types of effects will lead to a better understanding of the life cycles of AGN.