Adequate (or Statistical) Determinism
Adequate Determinism is the kind of determinism we have in the world. It is a statistical determinism, where the statistics are near to certainty for large macroscopic objects. Adequate Determinism also includes indeterminism, an irreducible property of the microscopic quantum world..
There is actually no strict determinism at any "level" of the physical world. Determinism is an abstract theoretical ideal that simplifies physical systems to allow the use of logical and mathematical methods like differential equations. The macroscopic statistical "determinism" we see is the consequence of averaging over extremely large numbers of microscopic particles. Statistical determinism is a corollary of the probabilistic "law of large numbers" when dealing with a great many independent events. Adequate determinism is the determinism of Newtonian physics, capable of sending men to the moon and back with astonishing accuracy. It is the determinism of those physiologists who think that quantum uncertainty is insignificant in the macromolecular structures of cell biology.
We are happy to agree with scientists and philosophers who feel that quantum effects are for the most part negligible in the macroscopic world. We particularly agree that they are negligible when considering the causally determined will and the causally determined actions set in motion by decisions of that will.
In particular, adequate or statistical determinism is all that determinist philosophers ever wanted or needed for moral responsibility.
Chance is need not be a direct cause of human actions. Quantum chance is primarily needed to generate unpredictable and "free" alternative possibilities for action.
Adequate determinism gives compatibilists the kind of free will that they need and that they say they want, namely the causal connection between motives, feelings, reason, character, values, etc. and the actions chosen from freely generated possibilities.
However, quantum mechanics is not negligible in some important cases. We know that quantum indeterminacy exists in the world. Sometimes microsopic indeterminism is amplified to produce unpredictable and uncaused events that show up in the macroscopic world to break the causal chains we normally see in adequate or statistical determinism.
Such new "uncaused causes" (causa sui) have not resulted in the collapse of reason or stopped the progress of science, as some philosophers and scientists feared. The Stoic Chrysippus, warned in the third century B.C.E.
"Everything that happens is followed by something else which depends on it by causal necessity. Likewise, everything that happens is preceded by something with which it is causally connected. For nothing exists or has come into being in the cosmos without a cause. The universe will be disrupted and disintegrate into pieces and cease to be a unity functioning as a single system, if any uncaused movement is introduced into it."
Certain "thought experiments" magnify microscopic quantum uncertainty to macroscopic levels. Perhaps the most famous is Schrödinger's Cat. Perhaps the most common are simple Geiger counters, which record the spontaneous radioactive decay of unstable atoms, much of it driven by cosmic radiation, a major source of genetic variation that drives natural selection.
None of these totally random events interferes in any significant way with the adequate determinism of the macroscopic world.
But it is random events that drive the creation of new species in biology and we can show that they underlie all creativity, all actions that bring new information into the universe, whether the formation of stars and galaxies or the writing of a new play.
Adequate determinism is one of the critical requirements for free will.