Kant’s Critiques: Pure Reason vs. Practical Reason

Posted on Dec 18, 2024 in Philosophy and ethics

Differences between Critique of Pure Reason and Critique of Practical Reason

I. Theoretical Use of Reason

The right to use theoretical knowledge is concerned. The Critique of Pure Reason is divided into three parts:

• Transcendental Aesthetic (how are mathematics possible?).
• Transcendental Analytic (what is physically possible?).
• Transcendental Dialectic (how is metaphysics possible?).

The Trial

• Definition: A trial is a proposition in which something is predicated of someone, i.e., in which something is affirmed or denied from someone. What is affirmed or denied is the predicate, and what is affirmed or denied is the subject.
• Classes: Trials are divided into two groups: those relating to whether the concept of the subject contains or not the concept of the predicate (analytic and synthetic) and based on the trial if the truth is known before or after experience (“a priori” and “a posteriori”).

• Analytical: This is one whose subject contains the predicate. Example: “The triangle has three sides.” In this kind of view, there is no contradiction, nor does the truth need to be checked by experience. Neither adds anything new to knowledge.
• Synthetic: It is one whose subject does not contain the predicate or something that belongs to its essence. I.e., “all canaries are yellow.” You can only affirm the truth of this trial after the experience.
• “A priori” is one whose truth is known before the experiment because its truth is evident. It is universal, necessary, and non-progressive. The first two characteristics are typical of science. It is a universal and necessary example. “Without exception, every triangle has three angles.” But it is not progressive because it increases our knowledge.
• “A posteriori” is that trial whose truth is known after the experience. It is not universal, it is not necessary, and is progressive because it increases knowledge.

Characteristics or Conditions of Any Science

For all science, it is possible to meet three essential characteristics.

• Universality: The truth of a trial has no exception. It belongs to the trials “a priori”.
• Necessity: The truth of a hearing is necessarily required. It belongs to the trials “a priori”.
• Progression: By broadening our knowledge of science. It is characteristic of synthetic judgments.

For Kant, the own judgments of science are “synthetic a priori” because they meet the three characteristics. These trials are necessary for science to be possible. That is, judgments that science needs to be universal, necessary (trials “a priori”) and that bring something new to knowledge (synthetic). Not only synthetic judgments or only “a priori” have the three characteristics necessary for science, but if the meeting between them.

How Can Mathematics and Science Exist?

If possible, as a science because it will give synthetic judgments a priori, i.e., it is given universality, necessity, and progressiveness. The universality and necessity are to mathematics as a way “a priori” of space and time, and escalations will be given by the feeling or subject.

Space and time are forms “a priori” of external and internal sensitivity, respectively. They are the forms where we introduce our perceptions.

• Forms: Molds or boxes where we put perceptions.
• “A priori”: These spaces are prior to all experience. There are so innate in us.
• Sensitivity: The ability to receive external data that strike our senses. Classes:
• Internal: This is the time; he perceived internal phenomena according to a chronological sense. I remember knowing, e.g., “A” prior to “B”.
• External: The space. E.g., “A” is before “B”.

How Can Physics Exist as a Science?

If possible, as a science because it will give synthetic judgments a priori, i.e., within them universality, needs, and progress. The synthetic or progressive is given by sensation or matter, and “a priori” or universal and necessary is given by the categories of understanding. These categories are:

Is it Possible for Metaphysics to Exist as a Science?

Kant says no, for three reasons:

• Scientists agree on their theories, not metaphysical.
• Science progresses; metaphysics lacks progressiveness.
• Metaphysics lacks one of the two elements necessary for the science that is the feeling or subject. Proof: The three objects of metaphysics are
• God.
• The world as a unit.
• The man or the soul.

Phenomenon and Noumenon

• Phenomenon is what appears to us or what appears to our senses, appearance. Therefore, we can define the phenomena as those objects of experience as our senses perceive. It is the appearance. It is the object of knowledge.
• Noumenon: Refers to what our mind sees beyond the phenomenon that can not perceive. It is the reality behind the appearance of the phenomenon. It is an object of knowledge.

Use of Practical Reason

Reason in its practical use is moral.

Origin of Kant’s Moral

• Why did Kant conceive of rigorous morality? Because of its relationship with the Pietist sect (Protestant).
• What is the starting point for his morale? Conscience or moral law.

Kant’s Moral Copernican Revolution

Kant performs three revolutions.

• In speaking knowledge of two elements: matter (empirical) and form (rational).
• Other than formal ethics material.

The Foundation of Moral Reason

Man is a natural and rational being:

• As a natural being, man is subject to nature, appetites, desires, affections, etc.
• As a rational being: Reason must end human behavior and master’s wishes and desires. Reason should guide man and must, therefore, be the source and subject of the moral law. We must find our own reason the standard of our conduct.

Will

• It is a strictly human faculty by which we determine to act according to certain laws or principles.
• Classes:

• Good Will: it is that will which is good in itself. Will estimated worth in itself, by the very reason and not by wishes, desires, goals, inclinations, etc. external to it. For Kant, goodwill is not the mere desire but the provision which leads the action.
• Pure Will: that which is moved for practical reasons.
• Impure Will: that which moves through an end or a fine.
• Holy Will: that he agreed with the subjective laws of reason.
• Autonomous Will: faculty by which one is determined to do likewise.
• Heteronomous Will: one that obeys the laws they enact others.
• Free Will: that which is subject to moral laws.

• The moral value of action: is having a good will. The solo is the will of the agent. The intent with which something is done, whatever the result.

Ethics

• Material Ethics: is the one that sends an action for selfish reasons (desire, pleasure, happiness, etc.). Kant rejects this ethic for three reasons:

• By not specifically carrying a good moral.
• In that hypothetical imperatives formula whose mandate is conditioned by interests, selfishness, pleasure, etc.
• Why is heteronomous, not autonomous, i.e., morality is determined to work for a well that she has not given itself.

• Formal Ethics: this ethic is one advocated by Kant to do something not for an end, but because it is our duty or the pure form of law.

Heteronomous and Autonomous Morality

• Autonomous Morality: it is one that commands to act on my own will or according to my conscience. According to the moral, man is autonomous and independent self-governing.
• Heteronomous Morality: is that commands us to do something alien to me early and whose desire is born of a strange foreign to me, therefore the will or malice of my action does not depend on me.

The Maxim and the Moral Law

• The maxim is a subjective practical principle. It is a rule that we impose on ourselves. To determine whether an action is morally good enough to ask if I can make my maxim become a universal law.
• The Moral Law: Kant distinguishes the practical principle objective in the law, a subject, and a way: the material is the desired object, and when we did, it is a pleasure that leads to selfishness. The form refers to the duty (categorical imperative). Its features are:

• Rational: that is rooted in reason, the rational being is the author of the law, the legislature, and the legislature.
• Practice: relation to what is done.
• Universal: that is objective.
• Required: that we should always obey since it comes from the right.
• Unconditional: by telling how we work:
• It must refer to beings as ends in themselves: that the human being should be considered as an end and never as a means.
• Imperative: that required to complete something.

The Imperative

• It is a mandate that requires action.
• There are two classes:

• Hypothetical: the act requiring a specific purpose, to get something. E.g., “study to pass.” This imperative commands conditionally and not absolutely, e.g., “take your medicine, and you will be well again.” The hypothetical imperative is legal for law-abiding moral but not fulfilling the law under such a condition. “I do not kill because I fear hell.” This action is legal but not moral.

The formula of this imperative is: “Make A if you want to B or B if you want to do A”.

Kant’s criticism is that the requirement is not proper to moral or human beings. It is typical of heteronomous ethics. The feature of moral duty is to send Kant unconditionally.

• Categorical: it is forced to do something so universal and unconditional. E.g., “studying”, “One should not steal.” The practice of law consists of the absolute value of the kingdom of ends. It is the only one who expresses a law practice. It is universal and necessary. The formula of this imperative is: “you should do A.” Kant talks about three ways:

• “Act so that the maxim of your will be first.”
• “Act so that you try the man only as an end, never as a means.”
• “Each one should be proposed as the ultimate and supreme the greatest good in the human world.”

The categorical imperative of duty practiced by moral duty. It is the only imperative apodictic value. It is the only one who can build a law for the will. An action is moral if it follows a categorical imperative.

Duty

Kantian morality is duty. The interests of the reason are summarized as follows:

• What can I know?
• What should I do?
• What can I expect?
• What is man?
• Duty is the need for action out of respect for the law; obligation contains a good will. It is the fulfillment of a moral law out of respect to it.
• Classes:

• Contrary to Duty: those which are not moral, to act against the duty to do so against the law.
• Conforming to Duty: to act according to law but against morality.
• On Duty: to act to oppose the natural inclinations to act morally. “He who kills for no dignity” acts only duty worthy. Our sole purpose is to fulfill the duty.

• Formula of duty: “always do the duty apart from the rest, as you need, as you need, you can. Responsibility is power.”
• Value morality of duty: an action has moral worth if done out of duty. You have to perform an action out of duty and never to achieve an advantage or selfishness. The virtue is respect for the duty.

The Human Being as an End in Itself

According to Kant, all beings are subject to a law that commands us to treat ourselves and all others “always as ends and never means.”

Why should the human being be an end in itself?

• Because it has an absolute value.
• Because based practice law.
• Because human nature is sublime and has dignity.
• Because it has the moral law itself.
• Because it will have an independent sovereign.
• Because it is a universal legislator. Man is a legislator and legislated.

Why we should not consider the human being as a means?

If we consider the human being as a means, it means that it has a relative value; it would be something contrary to morality; human beings would be considered a commodity. Human beings have dignity, but it is priceless.

The Kingdom of Ends

It is the systematic liaison of various rational beings by objective laws. It consists of a universal community of legislators that mark laws.

How do humans belong to the kingdom of ends?

It belongs as a member (the legislature becomes universal and is subject to those laws) and head (because being a legislator is not subject to the will of another).

Relationship between the kingdom of ends and the kingdom of nature.

There are two kingdoms: the purpose and nature. The kingdom of ends is only possible by analogy with a kingdom of nature.

How are the two kingdoms?

• Kingdom of Ends: this consists of maxims or rules that people impose.
• Kingdom of Nature is constituted by natural laws.

The intelligible world and the sensible world.

• Intelligible World: “is a set of beings as things in themselves,” i.e., a universal kingdom of ends where it lives under rational laws. It remains the same and is the basis of the material world.
• Sensible World: the world’s natural mechanism “whose natural laws result in heteronomy.” This world needs the intelligible.

The human being belongs to both worlds.

• To understand: “When we think of as free” and “when we behave as maximum freedom.”
• To the sensitive: “If we think of as required.”

The kingdom of ends is an ideal.

The kingdom of ends has no universal law; it has only an ideal.

The Person

The person is an individual of the human species.

For Kant, the person is free, autonomous, that is, laws can be yourself.

Postulates of Practical Reason

A postulate is a proposition or truth that is not evident in itself and can not be demonstrated by reason but must be accepted because it is needed. The postulates of practical reason are true that his reason failed to show pure practical reason but because they are required to ensure that there is moral. These postulates are:

• Human Freedom: Morality requires the existence of human freedom because if there is a duty, there must be human freedom; if we were not free, we should not be imposed.
• The immortality of the soul: The free will in our actions deserve reward or punishment for our actions, but sometimes it does not deserve to receive it, and therefore there must be another life where each was just reward, so it is necessary to immortality soul.
• Existence of God: For the reward or punishment are guaranteed in the afterlife, it is necessary to have a be a judge, well, powerful and just; that being is God.