But even the books written directly by Adler are encyclopedic in nature, especially his two-volume survey on freedom - The Idea of Freedom: A Dialectical Examination of the Conceptions of Freedom (1958) and its sequel The Idea of Freedom: A Dialectical Examination of the Controversies about Freedom (1961).

In The Idea of Freedom, vol.I, Adler classifies all freedoms into three categories:

• The Circumstantial Freedom of Self-Realization
• The Acquired Freedom of Self-Perfection
• The Natural Freedom of Self-Determination

The freedom we have identified as circumstantial is variously called "economic freedom," "political freedom," "civil liberty," "individual freedom," "the freedom of man in society," "freedom in relation to the state," and "external freedom." It is sometimes referred to negatively as "freedom from coercion or restraint," "freedom from restrictions," or "freedom from law," and sometimes positively as "freedom of action," "freedom of spontaneity," or "freedom under law."

(The Idea of Freedom, vol I, p.127)

Today most philosophers might include a large number of circumstantial internal constraints on freedom such as an agent's mental disabilities, addictions, behavioral conditioning, both normal and coercive (indoctrination or brainwashing), and perhaps even factors like heredity and environment.

Self-perfection is the idea from Plato to Kant that we are only free when our decisions are for reasons and we are not slaves to our passions (making moral choices rather than satisfying desires).

This is the acquired or learned knowledge to distinguish right from wrong, good from evil, true from false, etc. Adler also includes many theologically minded philosophers who argue that man is only free when following a divine moral law. Sinners, they say, do not have free will, which is odd because sinners are presumably responsible for evil in the world despite an omniscient and omnipotent God.

As signifying one of the three ways in which writers think that men possess freedom, the word "acquired" refers to that the possession of which depends upon a change or development in human beings whereby they have a state of mind, or character, or personality which differentiates them from other men.

Whatever word is used to designate this difference (whether it be "good," "wise," "virtuous," "righteous," "holy," "healthy," "sound," "flexible," etc.), the difference represents an improvement, or the attainment of a superior condition, as measured on whatever scale of values is posited by the particular writer.

Freedom, in other words, is thought to be possessed only in conjunction with a certain state of mind, character, or personality that marks one man as somehow "better" than another.

(The Idea of Freedom, vol I, p.135)

Self-determination covers the classic problem of free will. Are our actions "up to us," could we have done otherwise, are there alternative possibilities, or is everything simply part of a great causal chain leading to a single possible future?

Most of Adler's natural freedoms are compatibilisms. They include Hegel's freedom of a stone falling according to Newton's law of gravity.

Adler defines the natural freedom of self-determination as that which is not either circumstantial or acquired.

A freedom that is natural is one which is (i) inherent in all men, (ii) regardless of the circumstances under which they live and (iii) without regard to any state of mind or character which they may or may not acquire in the course of their lives.

(ibid., p.149)

We have employed the following descriptive formula to summarize the understanding of self-determination that is shared by authors who affirm man's possession of such freedom. They regard it, we have said, as "a freedom which is possessed by all men, in virtue of a power inherent in human nature, whereby a man is able to change his own character creatively by deciding for himself what he shall do or shall become."

We have further explained that "being able to change one's own character creatively by deciding for one's self what one shall do or shall become" expresses the topical agreement about self-determination only when at least two of the three following points are affirmed:

(i) that the decision is intrinsically unpredictable, i.e., given perfect knowledge of all relevant causes, the decision cannot be foreseen or predicted with certitude;

Adler may see a two-stage model, first alternative possibilities,
not causal factors,
then an act of will.

(ii) that the decision is not necessitated, i.e., the decision is always one of a number of alternative possible decisions any one of which it was simultaneously within the power of the self to cause, no matter what other antecedent or concurrent factors exercise a causal influence on the making of the decision;

(iii) that the decision flows from the causal initiative of the self, i.e., on the plane of natural or finite causes, the self is the uncaused cause of the decision it makes.

These three points, as we shall see, generate three distinct existential issues about man's natural freedom of self-determination. Writers who deny (iii) that, on the plane of natural or finite causes, there are any uncaused causes deny, in consequence, the existence of a freedom the conception of which posits such causes. Writers who deny (ii) that an effect can be caused in a manner which does not necessitate it deny, in consequence, the existence of a freedom the conception of which attributes to the self the power of causing but not necessitating the decisions it makes. The existence of self-determination is also denied by writers who claim (i) that God's omniscience excludes a freedom the conception of which involves the intrinsic unpredictability of decisions that are the product of man's power of self-determination

(The Idea of Freedom, vol II, p.225)

In his over 1400 pages, Adler devotes only six pages to brief comments on quantum mechanical indeterminism ⁵³ (v.1, p.461-466). Adler depends heavily on the thoughts of Max Planck and Erwin Schrödinger, who along with major thinkers like Einstein, Louis de Broglie, and David Bohm, rejected indeterminism.