Sandel's aim is to criticise the influential Kantian strand of liberalism. Kant was an Enlightenment philosopher of the 18th century. He wanted to find a way to make individual autonomy the basis of morality.
This meant that the moral law could not be based on a concept of good and evil. If an understanding of good and evil defined morality, then individuals could not choose for themselves their own ends.
Therefore, morality was to be based instead on a concept of justice or right. What Kant wanted to show was that justice or right, defined as possession of autonomy, could have primacy over the good.
But how can this position be justified? Some liberals, such as the 19th century English philosopher John Stuart Mill, have attempted a teleological justification. In other words, the principle is justified in terms of final human purposes or ends.
Mill argued that rights took primacy for utilitarian reasons, namely that this increased the sum of human happiness. Mill wrote:
I regard utility as the ultimate appeal on all ethical questions
Sandel summarises Mill's position as follows:
On the utilitarian view, principles of justice, like all other moral principles, take their character and colour from the end of happiness. For "questions of ends are…questions about what things are desirable", and happiness is desirable, in fact "the only thing desirable as an end", because "people do actually desire it".
Traditionalists would not, of course, reduce principles of justice and morality to the end of happiness. Kant also rejected such a view, believing that if happiness were the ultimate end that justice or right might not always be given primacy.
Kant instead looked for a deontological justification of the primacy of right, one which did not rely on final human purposes. He claimed to have found it in the idea that the human subject itself is prior to any of its objects just as the right is prior to any good.
For Kant, therefore, the human subject is not grounded within a particular nature or within particular relationships or within a moral universe leading on to an understanding of the good. The human subject is abstracted from all this.
Kant's position is very much in line with modern liberalism. This is how Sandel describes the Kantian view:
On the deontological view, what matters above all is not the ends we choose but our capacity to choose them.
And this is how Sandel describes the abstracted view of the human subject:
His answer is that the basis of the moral law is to be found in the subject… a subject capable of an autonomous will… Only such a subject could be that "something which elevates man above himself as a part of the world of sense" and enables him to participate in an ideal, unconditioned realm wholly independent of our social and psychological inclinations.
So if Kant is an important founder of modern liberalism, what can we say about his philosophy? Well, it places what is right and just in opposition to what is good. It has an abstracted view of man as a moral actor. It assumes that human communities cannot share important moral goods. And it dramatically reduces the significance of our moral choices preferring instead to focus on agency.