What is the difference between kant and hume

According to Hume,. To avoid circularity, there must be a motive to virtuous action that does not itself refer to the moral goodness of the act T 3. The two philosophers do not necessarily disagree here on the empirical question of what actually motivates people. Kant, in fact, seems comparatively skeptical; he expresses doubt that there have ever been human actions motivated from duty alone e.

They disagree sharply, however, on the normative question at issue. By contrast, Hume believes that such actions indicate a character flaw.

Indeed, if a person finds she is moved to act only by the sense that the action is good, she may very well reproach herself for a lack of generosity or gratitude, for example, and consequently form a desire to change her character. Hume and Kant both treat the concepts of virtue and vice as central to human morality. But they differ on the basic nature of virtue, and they present different catalogues of particular virtues and vices.

For this reason, Hume seems far more comfortable with the bourgeois virtues integral to successful participation in modern commercial and political society cf.

EPM 9. Vices, by contrast, are those traits that generate a displeasing sentiment of disapproval. The trait of prudence, for example, is a virtue because it tends to be pleasing to such a spectator. In other words, a trait is a virtue only insofar as it tends to provoke the moral sentiment of approval in a properly situated spectator. If it did not tend to provoke this response, it would not be a virtue. This marks a significant departure from Aristotelian conceptions of virtue Cohon Hume discusses a capacious catalogue of particular virtues and vices.

The question is not whether some virtues are fake or phony and others are authentic. The question is whether some depend on social rules and conventions and others do not. Organizing his catalogue by means of this distinction allows Hume to steer a middle path between those who see morality as entirely conventional e. According to Hume, some virtues do depend on social convention but others do not Cohon — In both cases, he seeks to explain why people tend to develop such traits and why they tend to be pleasing to judicious spectators.

Hume drops the artificial-natural distinction from the second Enquiry , but his investigations there are motivated by the same questions and the resulting view also steers a middle course between Mandeville and Hutcheson. According to the Treatise , artificial virtues include justice, fidelity to promises, allegiance to government, and chastity. Hume devotes much discussion to justice, which he treats as a paramount and paradigmatic artificial virtue.

Hume understands justice primarily as honesty with respect to property or conformity to conventions of property T 3. Establishing a system of property allows us to avoid conflict and enjoy the possession and use of various goods, so the social value of conventions involving property seems obvious. Yet one reason that justice receives such attention from Hume is that it poses a problem about moral motivation and moral approval.

Hume claims that there needs to be a natural non-moral motive for morally good actions, for otherwise they could only be done because they are morally good; and that would be circular, since our judgment of acts as morally good reflects our approval of the motives and traits that give rise to the acts in question T 3.

But this position makes it hard to see how justice can be a virtue; for it is hard to find the requisite natural, nonmoral motive for it. Self-interest is the natural motive that justifies our establishing rules regarding property T 3. Neither public nor private benevolence would do, since neither could motivate all just actions T 3.

But since sympathy with the public interest itself seems neither nonmoral nor inherent in human nature, this claim redescribes the problem rather than solves it.

Hume must ground sympathy for the public interest in more obviously natural sentiments, and explain its development from them e. Otherwise, Hume must abandon his claim that all morally good actions—even those associated with artificial virtues—have non-moral, natural motives. See Gauthier ; Mackie ch.

Among the natural virtues, Hume includes beneficence, prudence, temperance, frugality, industry, assiduity, enterprise, dexterity, generosity, and humanity T 3. In the second Enquiry , he distinguishes among virtues useful to others, virtues useful to oneself, virtues immediately agreeable to oneself, and virtues immediately agreeable to others.

Among qualities useful to ourselves are discretion, caution, enterprise, industry, assiduity, frugality, economy, good sense, prudence, discernment EPM 6.

Qualities immediately agreeable to oneself include cheerfulness, tranquility, benevolence, and delicacy of taste. Qualities immediately agreeable to others include good manners, politeness, wit, ingenuity, decency, cleanliness, and a graceful or genteel manner. What holds all these varied traits together as virtues is their evoking the sentiment of approval in spectators, itself grounded in sympathy.

Like Hume, Kant takes virtue to be central to human morality. According to Kant, virtue is the form in which a being with an imperfect or non-holy will expresses her supreme commitment to morality. Second, virtue is a kind of strength. Third, virtue presupposes opposition and entails internal struggle. Kant often seems to identify our inclinations as the primary opponents of morality G: ; V , ; C His considered view, however, is that inclinations are not the source of the problem.

It is because of radical evil that virtue implies struggle and demands strength. The fundamental task of the virtuous person is to achieve the proper ordering of her incentives, giving the moral law undisputed priority over self-love.

Virtue both expresses and promotes inner freedom. These duties are grounded in the moral law, the supreme principle of morality, which impresses itself on imperfect, finite rational beings like us as a categorical imperative.

Whatever duties we have must ultimately derive from this supreme moral principle. As Kant explains,. In accordance with this principle a human being is an end for himself as well as for others, and it is not enough that he is not authorized to use either himself or others merely as a means since he could then still be indifferent to them ; it is in itself his duty to make the human being as such his end.

Kant does not claim to derive these duties from the categorical imperative or the supreme principle of virtue alone. Rather, in moving from general principles of morality to moral duties, he draws on a variety of considerations regarding human nature and other aspects of the natural world. Hume and Kant share a number of influences, so we should not be surprised to see areas of overlap. First, like most eighteenth century philosophers, both regard the pursuit of virtue as central to human morality.

Fourth, their respective conceptions of virtue are secular by historical standards. Neither recognizes duties to God, for example, and neither counts piety or hope among the virtues. He follows Hume in rejecting fasting, self-flagellation, mortification of the flesh and other forms of physical self-chastisement and self-abasement as false virtues.

Kant condemns such attempts at. Yet there are striking and important differences between their views. Hume defines virtue in terms of the moral sentiments of a properly situated judicious spectator, and his definition makes virtue and vice dependent on such responses. Kant, by contrast, defines virtue in terms of duty, obligation, and law. A few additional differences are worth noting. First, both philosophers recognize and discuss a plurality of virtues and vices.

MM and Second, Hume casts a much wider net with regard to the qualities that count as virtues. The concepts of virtue and vice can apply to things outside our control, such as traits and motives that spring involuntarily from our basic temperament. Kant, by contrast, restricts the application of these concepts to traits, behaviors, and attitudes that are voluntarily adopted and cultivated as a matter of principle.

For Kant each virtue and each vice has its own maxim MM This would be true even of wit or good memory, for example. Wit and good memory are certainly things that an agent might cultivate for the sake of her natural perfection. A third important contrast concerns justice. Justice is an immensely significant virtue for Hume, but is not treated by Kant as a virtue at all. As long as one does not hinder their freedom in a way that violates universal law or legitimate positive law, one complies with the demands of justice.

It is a matter not of justice itself, but of ethics, if one respects the rights of others not from fear of punishment but from respect for persons or law. The moral worth adhering to acting rightly out of respect for right is not part of justice, but of ethics; it is a matter of self-constraint or virtue. Finally, their conceptions of moral vice are quite different.

For Hume a vice is a mental quality that provokes disapproval from a judicious spectator. Hume and Kant both believe that freedom is essential to morality. Moreover, both believe that a philosophical theory and vindication of human morality requires reconciling freedom with universal causal necessity determinism. However, they offer different conceptions of freedom, different ways of reconciling it with necessity, and different ways of understanding why this reconciliation matters for morality.

On this view, a person is free when, and only when, her action is not necessitated by any antecedent causes. Hume rejects this idea as unintelligible T 2. So the liberty of spontaneity is freedom from violence, but not freedom from necessity per se.

These are cases where we lack the liberty of spontaneity. But a person has such liberty whenever she is able to do what she wants to do. In such cases, her actions are causally necessitated, just like any other event in nature; but they are caused by motives that spring from her own character.

According to Hume, this is the form of liberty at issue in religion, morality, law, and common life. The liberty of spontaneity, as just described, is perfectly compatible with causal necessity.

There are two main reasons people often believe otherwise. First, we tend to conflate the two ideas of liberty. In cases where we enjoy the liberty of spontaneity, our experience suggests that we also enjoy something more. Yet this is a mistake explained by the blind spots of introspection. An outside observer, whether a friend or a scientist,. The second source of resistance to compatibilism stems from confusion about necessity.

People are prone to think that necessity rules out liberty because they conflate necessity with compulsion or force. They believe that when A causes B, A compels or forces B. Hume holds that this is a mistake, however. For example, experience shows that the vibration of a particular string is constantly conjoined with a particular sound. As a result, the mind develops the habit of immediately inferring the sound from the vibration EHU 7.

We believe that the sound is causally necessitated by the vibration, but the necessity is a product of the imagination, which associates the idea of the sound with the perception of the vibration. But in his later works, Kant explicitly identifies true virtue with a rationally grounded commitment to morality, not with an initially pathological feeling of affection which has been universalized and cooled off.

Interestingly, however, Kant makes comments about the importance of these assisting drives in his later works that echo those in Observations , even when they seem at least on the surface to sit ill with some of his other mature claims about the practicality of pure practical reason. Compare, for example, what Kant says in Observations with what he says in the Metaphysics of Morals :. Despite the appeal that sentimentalism clearly held for Kant in the s, by the late s it was a theme of Kant's notes and lectures that moral sense theories could not provide adequate accounts of moral obligation.

Arguments for this conclusion appear in Kant's later written works and lectures. In a number of works, Kant creates taxonomies of misguided, heteronomous ethical theories based on material determining grounds—in contrast to his theory of autonomy, in which the moral motive constitutes an objective, formal determining ground.

See Wood b. Kant distinguishes among these theories based on their accounts of the basis of moral obligation or the fundamental moral principle G —44; CPrR —41; C —54; M — Such theories may assume either subjective empirical or objective rational determining grounds for the moral principle; and within each of these categories, there are theories that assume these determining grounds are external, and others that assume they are internal.

Objective, internal grounds include perfection e. Objective, external grounds include the will of God e. Subjective, external grounds include education e. Subjective, internal grounds can include physical feeling, such as self-love e. Thus, Kant locates moral sense theories among those theories that assume a subjective, empirical, internal determining ground of moral feeling as the principle of morality:. Kant displays some level of relative approval for the moral sense theories. He compares them favorably with theories of self-interest, for example.

Ultimately, of course, sentimentalism, along with all other attempts to ground morality in material determining grounds, fails in Kant's view. Kant has a lengthy list of related reasons why moral sense theories are inadequate. No empirical principles can ground moral laws, because moral laws bind all rational beings universally, necessarily, and unconditionally; empirical principles, however, are contingent in various ways, for example, on aspects of human nature G — Variance in moral feelings makes them an inadequate standard of good and evil G Moral feelings cannot be the source of the supreme moral principle, because the supreme moral principle holds for all rational beings, whereas feelings differ from person to person M If duty were grounded in feeling, it would seem that morality would bind some people e.

Even if people were in complete agreement regarding their moral feelings, the universality of these feelings would be a contingent matter, and thus an inadequate ground for the unconditionally binding moral law. Indeed, if morality were grounded in feeling, it would be arbitrary: God could have constituted us so that we would get from vice the pleasurable, calm feelings of approval that we now allegedly get from virtue M So for Kant, the contingency of the ground of obligation offered by moral sense theories renders those theories inadequate; only a priori determining grounds will do.

Nevertheless, we can see the extent of the influence of moral sense theories on Kant's ethics in the way that moral feeling continued to figure in Kant's moral thought long after he rejected moral sense theories as heteronomous. Kant states in his notes that moral sense theories are better understood as providing a hypothesis explaining why we in fact feel approval and disapproval of various actions than as supplying a principle that justifies approval or disapproval or that guides actions NF As I have noted, Kant's later works give an important role to certain moral feelings—moral feeling, conscience, self-respect, and love of one's neighbor—as constituting subjective conditions for moral obligation.

Although Kant takes many pathological feelings such as sympathy and parental love to be of vast moral usefulness, and worthy of cultivation for moral purposes, Kant puts conscience, moral feeling, self-respect, and love of one's neighbor in a special category of feelings. As early perhaps as , Kant can be seen to be giving moral feeling a special status in relation to reason. Kant's treatment of moral feeling is surely one of the more significant ways in which he integrates what he sees as the valuable insights of moral sense theorists into his own theory.

As attention to Hume's arguments in the Enquiry will reveal, however, the kind of liberty that Hume ascribes to human beings is more superficial—more an account of freedom of action—than what is often desired by those arguing for freedom of the will.

Indeed, for Hume, the very notion of will is problematic. Hume begins his discussion in the Enquiry by suggesting that ambiguities in language have kept interlocutors in the debate over freedom of the will talking past one another.

Hume sets out to clarify what we can best be understood to mean when we talk about liberty and necessity, and to show that so understood, there is no conflict between them. He discusses necessity first. It is on the basis of the observed uniformity among human actions that we draw inferences concerning them, just as it is on the basis of observed uniformity among events in the natural world that we draw inferences concerning them ECHU Given that Hume's claim is that we all, if we reflect honestly and carefully, can recognize that we are committed to accepting this sort of necessity's pertaining to human actions, it is imperative that Hume explain why so many people have thought that human actions are not determined in the way that natural events are.

He locates the problem in part in a reluctance to accept his general account of necessity as a mere link the mind makes between one object or event and another based on experience of their correlation:. Any such view of liberty would fly in the face of both common and philosophical ways of thinking about human action.

Hume argues that his notions of liberty and necessity are not only consistent with each other, but that both of them are consistent with, and even essential to, basic moral and legal practices ECHU 65— For example, we are far more condemnatory in blaming and punishing someone for an act we regard as caused by an enduring trait, motive, or inclination than one we regard as caused by a fleeting feeling, which is less deeply a part of that person.

And it would make no sense at all to blame someone for an action the cause of which lay entirely outside her. Hume gives a mixed verdict to questions about whether his arguments about liberty and necessity pose problems for beliefs about God's omnipotence and beneficence, arguing that while some standard arguments can handle one type of concern that might arise, not all such concerns can be so easily dealt with ECHU 66— Kant shares Hume's view that causal necessity governs human actions and other events, insofar as they are all considered part of the natural world, and that humans are nonetheless free.

But Kant rejects Hume's view that moral and natural actions must be viewed as part of a single chain of causes, effects, and explanations. Indeed, if they were, and if we accepted natural causal laws as universal and deterministic, there could be no freedom of the sort Kant is ultimately after for his moral philosophy i. Kant renders freedom and determinism consistent by distinguishing between two worlds of which we are members.

As members of the phenomenal world, our actions can be understood in purely deterministic terms, according to natural causal laws; but as members of the noumenal world, we are free. Kant also rejects Hume's account of necessity:. To provide a rough sense of Kant's theory of freedom, I will set out a few of Kant's claims and arguments about freedom from the Critique of Pure Reason , the Groundwork for the Metaphysics of Morals , and the Critique of Practical Reason. Before I do, however, I want to mention a couple of aspects of his view that I will not discuss in those contexts.

Wille is the legislative aspect; it is through Wille that rational beings give our selves the law; and it is Wille that Kant identifies with pure practical reason. Wille is itself neither free nor unfree. The most important arguments regarding freedom in Kant's first Critique concern the Third Antinomy. In this work, Kant is primarily concerned with transcendental freedom, though also to a lesser degree with the practical freedom which depends on it. Kant's antinomies present arguments for two contradictory positions, illustrating the contradictions into which reason falls when it fails to recognize its own bounds.

The Third Antinomy concerns freedom and natural necessity. The thesis claims that the explanation of appearances i. The antithesis claims that there is no freedom, and that causation occurs only in accordance with laws of nature.

Kant's solution is to argue that freedom and determinism are not impossible to reconcile, if we posit two different points of view standpoints : the standpoint he associates with the intelligible or noumenal world, according to which we are wholly independent of causal laws and instead subject to our own laws, and the standpoint he associates with the sensible or phenomenal world, according to which we are determined according to natural causal laws.

Kant even suggests that natural causal laws are themselves an effect of intelligible causation. Kant maintains that the human will has an empirical character that can be studied, and is properly thought of as the empirical cause of our actions. It is important to note, however, that Kant recognizes that it is impossible for us to say much of anything about the intelligible world itself, or how it underlies the sensible world.

Kant's main argument concerning freedom in the Groundwork takes place in section III, where he seeks to establish the supreme moral principle by showing that the categorical imperative is valid for rational agents. This argument has two main premises: that the moral law is the law of the free will, and that rational beings must regard themselves as free; the conclusion is that rational beings must regard themselves as subject to the moral law G —48; Korsgaard , ch.

A will must have a law, since the very concept of cause implies a law-governed relation between cause and effect. A negatively free will cannot be heteronomous; so it must be autonomous. The discussion of autonomy in section two of the Groundwork already identifies autonomy with morality and the principle of autonomy with the moral law; so the moral law is the law of the free will.

They must ascribe this freedom to all other rational beings as well as to themselves. So, since we inevitably ascribe freedom to ourselves, and since the moral law is the law of the free will, we must take ourselves to be bound by the moral law. Kant follows up this argument with one that concerns the interest we take in the moral law, and an apparent circle in Kant's account of it.

We cannot rationally regard the moral law as issuing duties to us unless we take ourselves to be free—in whatever way is necessary—for us to comply with those duties. On freedom, especially in the second Critique , see Beck , ch. Many aspects of Kant's arguments concerning freedom have raised questions. One objection is that at least in the Groundwork and second Critique Kant equivocates between two conceptions of freedom—one that is necessary for moral responsibility, and one that Kant identifies with moral goodness—and as a result, is left with the embarrassing position according to which only morally good wills are morally responsible Sidgwick ; cf.

Wood , 78— Another concern is that at least in Groundwork section III the kind of freedom that Kant argues we must ascribe to ourselves as rational beings is insufficient for moral freedom autonomy , and that Kant does not recognize this Allison , — There also questions about the development of Kant's theory of freedom, and the consistency of his positions and arguments, and the shifting role of freedom in Kant's philosophy Schneewind , chs.

The distinction between noumena and phenomena is without a doubt one of the most controversial aspects of Kant's ethics—and of his philosophy as a whole. Kantians have interpreted it differently. Some have understood Kant to be making a metaphysical or ontological claim when he distinguishes between noumenal and phenomenal worlds. Others have understood Kant to be distinguishing between only different standpoints we take, identifying the noumenal world with the practical standpoint that we take when we think of ourselves as autonomous, responsible beings, and the phenomenal world with the theoretical standpoint we take when we think of ourselves as part of the natural, deterministic, empirical world Beck , —94; Korsgaard a, esp.

There are concerns about both. Many find the notion of two worlds metaphysically cumbersome; but some raise doubts about whether the two standpoints approach is adequate for transcendental and practical freedom see Irwin , esp. He is not claiming that reason has no role in human action, but rather that its role is an auxiliary one; the motivating force behind an action must come from passion.

Hume's main arguments for the limited role of reason are found in the Treatise of Human Nature. There is debate among interpreters about whether Hume changed his position on reason and motivation between the Treatise and the second Enquiry , as well as precisely what Hume's understanding of the nature, extent, and significance of reason's contribution to action is see, e. Abstract or demonstrative reasoning, which involves a priori inferences and judgments pertaining to relations of ideas, cannot influence the will, but only assist us in our pursuit of an end we already have e.

In order to be motivated to act, we must first anticipate pleasure or pain from something. That anticipated pleasure or pain gives rise to feelings of desire or aversion for the object in question. Probable reasoning allows us to discern the causes of this object; our positive or negative feelings about the object then spread to the causes of it; and we are then motivated to pursue or avoid them.

Simply believing that one thing causes another will not motivate action; there must be a desire, fear, or other passion T — The only thing that can oppose an impulse to action generated by one passion is a contrary impulse.

Reason, then, could counteract an impulse to action generated by a passion if and only if reason could itself generate a contrary impulse. But from the first argument, we know that that reason cannot generate such an impulse. Hume goes on to say that whatever we feel in us running contrary to an impulse to act that we mistake for reason must be something else, such as a calm passion e.

So a passion cannot be contrary to truth and reason. Passions cannot, strictly speaking, be evaluated as reasonable or unreasonable, despite our practice of calling passions unreasonable or irrational when they depend in some way on poor reasoning or false beliefs.

Later in the Treatise , Hume extends this argument to volitions and actions as well T ; we might view Kant's conflict in conception and contradiction in will tests of the formula of universal law to constitute refutations of the latter argument G —24; Guyer , ch. These arguments convey Hume's positions that passion plays the dominant role in motivating action, reason a merely subsidiary role; reason cannot control or resist passion's motivational influence; and one cannot use the standards of reason to praise or criticize passions.

Hume draws some further important, anti-rationalist moral conclusions, partly on the basis of these views and arguments on reason, passion, and motivation generally. One obvious implication is that reason cannot be the motive to moral action; if reason cannot motivate any sort of action, it cannot motivate moral action. Reason of itself is utterly impotent in this particular.

Moreover, we can say, in keeping with the third argument, that an act's rightness or wrongness cannot consist in its reasonableness or unreasonableness, because acts cannot, strictly speaking be reasonable or unreasonable T A third further conclusion is that reason cannot discover morality or fundamental moral principles or distinctions. Virtue and vice, and other aspects of morality are beyond the purview of demonstrative reasoning, which concerns the relations of resemblance, contrariety, degrees in quality, and proportions in quantity and number T — And the moral goodness for example of an action cannot be reduced to its cause or effect, or to other matters of fact that probable or causal reasoning can supply T — In sum, then, Hume argues that the source of morality, our means of discerning moral distinctions, and the spring of moral motivation, must be the passions.

For Kant, by contrast, reason not feeling is the source of morality, of moral motivation, and of our grasp of moral obligation. In Kant's view, only if pure practical reason is the source of morality can morality categorically, necessarily, and universally, bind all rational beings:.

The example of not lying seems ill-chosen, because Kant's own theory does not treat it as a fundamental moral requirement, but rather as a duty derived from a fundamental requirement MM — Nevertheless, this passage shows how Kant's conception of moral obligation implies that morality and its basic principles have a purely rational source.

When it comes to moral epistemology, feelings certainly have a role to play, but the role comes fairly late in the game. It is through reason that we discover basic moral principles; but judgment, experience, and cultivated feelings—all within the realm of what the average person can attain—can aid us in our use of these principles G , , —; MM , — Furthermore, it is important to remember that for Kant, moral epistemology is not a matter of discovering some external, independently created set of moral rules, but rather recognizing a rationally self-legislated moral law.

Ameriks , ch. Moreover, much of what we see Kant doing in the first two sections of the Groundwork is leading us from compelling assumptions about value and moral obligation, through arguments about the nature of rationality and the commitments inextricably linked to our rational nature, and to formulations of the categorical imperative.

Kant says of right actions:. Yet the way reason motivates finite rational beings such as humans to act rightly is by means of feelings. In the Groundwork , Kant focuses on respect for the law mentioned above. But Kant goes on to describe respect for the law in a way that makes it sound more like a separate feeling, though one arising from reason:.

In the Critique of Practical Reason , Kant describes the special moral feeling of respect for the law as having both a painful aspect, involving the humiliation the agent feels as the moral law strikes down her self-conceit, and a pleasurable, ennobling aspect, since the moral law comes from her own pure reason, and represents her own higher self and vocation CPrR In the Metaphysics of Morals , Kant lists moral feeling, conscience, love of human beings, and respect for oneself as special kinds of feelings of which we are made aware only though consciousness of the moral law MM Since our compliance with duty presupposes our having these feelings, there is no duty for us to have them.

There is a duty to cultivate them, however, because of their moral usefulness. Kant is explicit that feelings—especially pleasure or satisfaction and pain or displeasure , both actual and anticipated—are essential to human moral motivation Guyer , ch. In the Critique of Practical Reason , Kant suggests that the painful feeling of having one's self-conceit struck down is a necessary part, or perhaps condition, of moral motivation.

The agent must see the moral law, not her own inclinations, as legislative for her in order to be morally motivated. What is so important about respect for the law, moral feeling, and other rationally grounded feelings is that through them human beings are able to feel pleasure or displeasure solely by considering the morality of our actions.

In spite of the foregoing, Kant may nevertheless appear hostile to our natural, sensibly-grounded human emotions. Apathy and self-mastery are essential for expressing and protecting inner freedom, which can be threatened by affects and passions.

He was of Scottish descent and had a Pietist upbringing and education. Pietism is a form of Protestantism similar to Methodism, i. He taught as a privatdozent, which is a private teacher or tutor, paid by his students. This meant a poor life, boardinghouses, and bachelorhood. He began with an interest in science -- physics, astronomy, geology, biology.

In fact, he introduced the nebular hypothesis, suggesting that originally, swirling gases condensed into the sun and the planets -- basically, what we understand to be the reality today. In , he published the Critique of Pure Reason.

This is frequently misunderstood to mean that he was outraged. Actually, he said that he had been dogmatically accepting of the traditional ideas about reason. Hume enlightened him! However, it is also true that Hume challenged him, in a sense, to rescue such concepts as cause and effect, which Kant felt were essential to the existence of science. He took as his life's task to saving of the universe from Hume's pervasive skepticism.

First, he makes a distinction between a posteriori and a priori knowledge:. Although all our knowledge begins with experience, it does not follow that it arises entirely from experience. For it is quite possible that our empirical knowledge is a compound of that which we receive through impressions and that which our own faculty of knowing incited by impressions supplies from itself--a supplement to impressions which we do not distinguish from that raw material i.

Since the capacity to be affected by objects must precede all perception of these objects, it can readily be understood how the form of all appearances i. It is, therefore, solely from the human standpoint that we can speak of space, of extended things.

If we depart from the subjective, the representation of space stands for nothing whatsoever. Time is a purely subjective condition of our human perception, and, in itself, apart from the subject, is nothing What we are maintaining is the empirical reality of time, its objective validity of all objects which allow of ever being given to our senses.

Since our perception is always sensible i. On the other hand, we deny to time any claim to absolute reality; that is to say, we deny that it belongs to things absolutely, as their condition or property independently of any reference to the form of our perception. Properties that belong to things in themselves can never be given to us through the senses.

This, then, is what constitutes the ideality of time. Relation: substance and accidents, cause and effect, reciprocity between active and passive. Suppose morality necessarily presupposed freedom of the will while speculative reason had proved that such freedom cannot even be thought. In such case freedom, and with it morality, would have to make room for the mechanical interpretation of nature. But our critique has revealed our inevitable ignorance of things-in-themselves, has limited our knowledge to mere phenomena.

So, as morality requires only that freedom should not entail a contradiction, there is no reason why freedom would be denied to will, considered as a thing-in-itself, merely because it must be denied to it as a phenomenon. A note on Frederick the Great: The King of Prussia, including much of Germany as well, he was, besides a consummate leader and politician, an accomplished philosopher and a passionate amateur musician.

In , Kant wrote the Critique of Practical Reason. Practical reason refers to the making of moral decisions. In this book, he argues that everyone has a conscience, a moral law within their souls, not unlike the categories of the Critique of Pure Reason.

This moral law he calls the Categorical Imperative , which is phrased two ways. The first is a variation on the Golden Rule: Whatever you do, consider what kind of world this would be if everybody did the same.

Pursuing of one's actual self-interest never conflicts with the demands of morality. Since, for Plato, it is more rational to pursue one's real, than one's apparent, self-interest, rationality and morality do not conflict. It is rational to be moral. Plato rejects the contractarian reconciliation of morality with individual rationality primarily because the thinks that the contractarian conception assumes that a person's motives for being just are necessarily based her self-interest, while our concept of the just person holds that to be truly just one must value justice for its own sake.

It entails that as long as a person acts in a moral way then the consequences of the actions do not matter. Instead, it is the matter of duty, acting out of respect for the moral law. Actions of any sort, he believed, must be undertaken from a sense of duty dictated by reason, and no action performed for appropriateness or solely in obedience to law or custom can be regarded as moral. A moral act is an act done for the "right" reasons.

Kant would argue that to make a promise for the wrong reason is not moral you might as well not make the promise. When considering the Platonic form of goodness, Kant's idea of the good will is similar in that it adheres to a theoretical universal, and that reason is essential to its discovery. However, the concept of the Golden Rule is not important to Plato and he would certainly scoff at the exclusivity of the term "moral.

He focuses only on the reasoning and puts these intentions into a duty and good will definition. When a person does an action out of duty, it is because the duty is something a person is ought to do, deeming the action to be morally worthy. His theory offers a view of morality based on the principle of good will and duty. According to him, people can perform good actions solely by good intentions without any considerations to consequences.

In addition, one must follow the laws and the categorical imperative in order to act in accordance with and from duty. This is Kant's proof of Freedom.