Reading Guide: CPrR
Reminder of Goals in Critique of Practical Reason
 Goal: To identify the law that every rational being must be subject to simply by having reason and will
(concludes this on p.29)
 Goal: To establish that pure reason is practical (i.e. it can provide guidance to the will of itself) [Kant’s
position] and to disprove the assumption that only empirically conditioned reason can determine the will
[Hume’s position]
Terminology-based exposition of Practical Reason, Analytic, p.17-30
WILL
 is the capacity for spontaneous activity; a causal power independent of determination by empirical conditions
and laws of nature (as cognition of physical objects)
 is “a faculty either of producing objects corresponding to representations OR of determining itself to effect
such objects” (12)
PRACTICAL PRINCIPLES, MAXIMS, LAWS
 principles are propositions that contain determinations of the will via practical rules
 practical rules are products of practical reasoning that prescribe action as a means to an effect, and this
prescription can be either:
a. subjective principles, or maxims, have conditions which are thought to apply only to the subject’s will
b. objective principles, or laws, have conditions which are thought to apply to every rational will
IMPERATIVES: PRECEPTS & LAWS
 Imperatives are practical rules that express an ought and can take two forms:
a. Hypothetical imperatives, or practical precepts determine the conditions of the causality of the agent
with respect to an effect and its adequacy to achieve that effect.
[these tell the will what it ought to do under specific conditions]
“One ought to exercise regularly if you want to stay fit!”
b. Categorical imperatives, or practical laws, determine the will only, independent of a subject’s desires
or possible rationalizations, physical capabilities.
[these tell the will what it ought to do regardless of conditions]
“One ought never to promise something you never intend to do!”
THINKING MAXIMS AS POSSIBLE CATEGORICAL IMPERATIVES (p.24-5)
 For a maxim to be fit for law, it must be formalized and abstracted from all consideration of ends and
particular desires, subjective concerns. Only the form is thought, and then posited as a law; that is, you
imagine every will mechanistically enacting this formalized maxim as though it were law for everyone in all
cases.
 If your maxim, formalized and universalized, destroys itself (that is, it would make it so that such a choice
would never arise), it cannot be a practical law.
RECIPROCITY OF FREEDOM & MORAL LAW (see p.26, problems)
1. Freedom is the ratio essendi of moral law: i.e. Freedom is that in virtue of which moral law exists.
2. Moral Law is the ratio cognoscendi of freedom; i.e. Moral Law is that in virtue of which freedom is known to
exist.
That is, our freedom is the reason moral law must exist, since we’re not determined mechanistically as sensible
beings (objects) of the laws of nature, there must be a law that applies to us in our supersensible being (viz. moral
law).
Also, reciprocally, the moral law’s existence (as a fact of reason) enables us to know our own freedom.
Andrews Reath’s intro comment on this (p.xxiii):
A. If the agent’s basic principle is to act only from maxims with the form of law (moral law), the agent is
transcendentally free
B. If an agent has a free will, then the moral law is the basic principle of its will
MORAL LAW, FACT OF REASON (p.27-8)
(a.k.a. fundamental law of practical reason, supreme principle of practical laws)
 is the determining ground of the pure will (unconditioned willing)
 its validity is a “fact of reason,” which is our consciousness of the “law-giving activity of reason” (see p.28,
bottom for more)
 we become “immediately conscious” of the moral law (not in its propositional form stated in §7, obviously,
but rather the possibility of lawfulness in our maxims) once we represent our own maxims to ourselves. We
do not do this in the chaos of immanent moral choices and actions, but only in reflection. We only “know”
this retroactively.
[Personal comment]:
Hence, Kant does not have to conclude Hume is all wrong, just ungrounded and incomplete. Custom and
habit are part of moral experience as reflective moral cultivation, but this can NEVER be the ground and
complete account of our morality. In this sense, moral cultivation would not be coming up with a set of
categorical imperatives to apply to all events (since moral events are almost always singular), but rather in
educating your moral vision or awareness, which is to say your imagination. And how, we might ask, can we
best do that?
 stated as an imperative, it is categorical: “So act that the maxim of your will could always hold at the same
time as a principle in a giving of universal law” (§7, p.28)
 respect for the moral law is the immediate recognition of, or feeling produced by the recognition of the
authority of morality
FREEDOM
 the validity of the moral law reveals our freedom, or put another way, the “fact of reason” (consciousness of
our ability to act in accordance with moral law when holding our maxims up to its form) discloses the reality
of our transcendental freedom, our supersensible nature (which is opposed to our sensible nature, which is
always known through laws of natural mechanisms via theoretical reason)
 it is incomprehensible but indispensible in theoretical reason (it cannot be conceptualized, only necessarily
thought)
 it is the functional ground of practical reason, known only by the fact that we can be self-determining by
reason alone (which is not to say we always choose to be determined by reason). Through the moral law,
reason is unconditionally practical, that is, it has the ability to guide the will without being limited by
empirical matters.
Moral Law vs. Natural Law (see note * on p.5)
-ML = causality through transcendental freedom (moral law)
[human being as a being in itself; non-sensible pure consciousness]
-NL = causality through laws of appearance (natural law)
[human being as appearance; empirical consciousness]
RATIONAL vs. HOLY WILL
 a rational will has the “ability to determine their causality by representation of rules” in reason (pure practical
will), and to hold the maxim of an action up to the law0giving form of that will (the moral law). The maxim is
not the law itself because we are finite beings who are “affected by needs and sensible motives” (29).
 a holy will is not capable of a maxim (principle of action) that conflicts with the moral law; this will is a
practical idea as a model (paradigm) which can only be approximated.
AUTONOMY, HETERONOMY
 moral law expresses the autonomy of pure practical reason (freedom), which is the formal condition of all
maxims in their ability to be in accord with that moral law