Hume vs. Kant
On the Nature of Morality
From the origin of Western philosophical thought, there has been an interest in moral laws. As Hume points out in the Treatise, morality is a subject that interests us above all others (David Hume A Treatise of Human Nature’). Originally, thoughts of how to live were centered on the issue of having the most satisfying life, with virtue governing one’s relations to others (J.B. Schneewind ‘Modern Moral Philosophy’). However, the view that there is one way to live that is best for everyone and the view that morality is determined by God, came to be questioned, and it is this that led to the emergence of Modern moral philosophy.
The moral debates continued to see good as merely that which gives happiness or pleasure. it was assumed that what we ought to do is always a function of what it would be good to bring about: action can only be right because it produces good (J.B. Schneewind ‘Modern Moral Philosophy’). It was the breaking away from this idea that was perhaps the most important aspect of the works of both Immanuel Kant (1724-1804) and David Hume (1711-1776).
Hume’s moral theory arose out of his belief that reason alone can never cause action. Desire or feelings cause action. Because reason alone can never cause action, morality is rooted in our feelings. Virtue arises from acting on a desire to help others. Hume’s moral theory is therefore a virtue-centered morality rather than the natural-law morality, which saw morality as coming from God.
Kant’s notion of morality arose from his notion of a moral law; a law applicable to all people at all times, that imposes absolute duties on us. According to Kant, you ought to act according to the maxim that is qualified for universal law giving; that is, you ought to act so that the maxim of your action may become a universal law (Immanuel Kant ‘Lectures of Mr. Kant on the Metaphysics of Morals’). Kant, unlike Hume, saw it as possible to act on reason alone, and whether or not a person acted morally depended on whether he/she had acted on reason alone.
The essential difference between Kant and Hume that affected their whole thinking on the matter of morality was each one’s belief about the autonomy of the will. Kant saw the will as fully autonomous and therefore needing no external sources for motivation, thus making it possible to act out of reason alone.
This view went completely against that put forward by Hume. Hume believed that reason is, and ought only to be, the slave of the passions. He argued that reason is used to discover the causes of pain or pleasure, but it is the prospect of pain or pleasure that causes action, not the reasoning alone, as that is entirely indifferent to us. This notion of always being motivated by pleasure or pain is very important, as it follows from this that when we act morally, it is a desire that makes us act and not reason. Since morals, therefore, have an influence on the actions and affections, if follows that they cannot be derived from reason, and that because reason alone, as we have already proved, can never have any such influence. Morals excite passions, and produce or prevent actions. Reason of itself is utterly impotent in this particular. The rules of morality, therefore, are not conclusions of our reason (David Hume ‘A Treatise of Human Nature’).
Kant saw it as essential that the will must not be the slave of the passions for moral actions to be possible. Kant differentiated two kinds of imperative statements: first, the hypothetical imperative, which has the general for If you want to achieve P then you should do X; and, second, the categorical imperative, of the form You should do X.
Hypothetical imperatives are unproblematic. They are straightforward sentences that express mundane statements of fact. Categorical ones, on the other hand, are highly problematic. My own reaction to any categorical imperative is to ask, Why?. For instance, if a rabbi tells me You should refrain from eating pork, then that appears to me to be an incomplete statement. I immediately want to hear the missing half of the statement, which would answer the question Why should I refrain from eating pork?. Or better, What will happen to me if I do eat pork?. The Kantians do not try to answer the question why. Instead, they tell people that they shouldn’t worry about why because the question Why? is meaningless when interrogating a categorical imperative. Since most people do not have a background of analytical philosophy, they feel obliged to accept this imperative.
In Kant’s view, only if a person is acting solely on the categorical imperative such as doing something out of duty, can the act be morally good. This is because if somebody is acting out of the hypothetical imperative, he/she has an ulterior motive in acting in that way and are therefore not acting out of duty but are pursuing a certain end. They need not be acting in self-interest, but if they act because of a desire to act in that way, this is not morally worthy. You can still act morally if it gives you pleasure, as long as the reason for your action is solely out of duty.
Kant gives the example of someone who without any motive of self-interest finds joy in helping others. They act out of the pleasure that it gives them to do so. In this case the person’s action (though we may applaud them for it) has no true moral worth. It is only if his mind be clouded over with his own sorrow so that all sympathy with the lot of others is extinguished, and that though no motivation moves him any longer, he never the less tears himself from his deadly insensibility and performs the (moral) action without any inclination at all, but solely from duty, that for the first time his action has genuine moral worth (Immanuel Kant, ‘Grounding for the Metaphysics of Morals’).
The final important argument that Hume levels against those that see reason alone as able to motivate is his ‘is and ought’ argument. On the rationalist system, virtue and vice are discovered by reason alone through facts or relations. Whereas with the hypothetical imperative it is relatively simple to see why someone acts, as they act in order to achieve some goal (ie. If you want x then you ought to do y), it does not follow from a fact (‘is’ statement) that you ought to pursue a certain course of action. As Hume points out No imperative conclusion can be validly drawn from a set of premises which does not contain at least one imperativeIn this logical ruleis to be found the bases of Hume’s celebrated observation on the impossibility of deducing an ‘ought’-proposition from a series of ‘is’-propositions (R.M. Hare ‘The Language of Morals’).
One problem with the Humean notion of morality though is that if morality is based on an individual’s sentiment, how can we have any absolute, universal notion of morality? Won’t every individual simply have his/her own morality?
Hume replies that underneath each rational being’s own morality, there will be a deeper universal morality in basic notions such as justice, etc. However, I couldn’t find any convincing justification of this idea.
So, how does Kant answer the objection that a categorical imperative will never alone lead to action? He cannot use examples of reason alone motivating, as we can never tell that subconsciously or otherwise another factor isn’t in fact involved. He therefore will have to prove the possibility of the categorical imperative being applied in reality a priori. He argues in the third section of the ‘Grounding for the Metaphysics of Morals’ that they key to moral action is freedom of the will. He still though doesn’t explain how a categorical imperative can motivate.
His answer is in fact fairly disappointing. He argues that we all take a great deal of interest in the moral law, and that the moral law is valid for us not because it interests us, but rather, the moral law interests us because it is valid for us as men, since it has sprung from our will as intelligence and hence from our proper self (Immanuel Kant ‘Grounding for the Metaphysics of Morals’). He says that there is no possibility in knowing why we are interested in universal maxims and therefore morality, as the rational part of us exists outside time and space and we can therefore not achieve any understanding of it is this world.
I do not see this as a satisfactory answer in any way. Having based his entire view of morality on the idea of the categorical imperative, Kant is unable to substantiate his claim that we are capable of acting on reason alone. He merely dodges the issue by saying that there is no possibility of understanding how a categorical imperative can motivate.
However, this does not invalidate the rest of Kant’s argument in the least. It is still possible to argue that morality can only occur through the categorical imperative while holding the Humean idea that reason alone can never motivate, and so conclude that morality doesn’t exist in reality.
In conclusion, we can see that both the two theories have a number of things in common as well as some important differences. Both made a significant break with past moral theorists in putting forward a morality that does not according to Kant needthe idea of another being above man, for a man to recognize his duty (quoted in ‘The Concise Encyclopedia of Western Philosophy and Philosophers’ Ed. J.O. Urmson). Whereas past moral theories had seen duties as laid down by God, Hume and Kant saw morality as rooted in humans themselves.
However from here the theories diverge. Hume sees moral judgements as being caused by sentiments of pain or pleasure within an agent as reason alone can never motivate, whereas Kant see the only moral actions as being those caused by reason alone, or the categorical imperative. I think that both theories have a problem with coming up with absolute moral laws – Hume’s theory because absolute morality would appear to be impossible if morality is based on an individual’s sentiment, and Kant’s theory because it cannot prove the existence of the categorical imperative.