These are two different principles of justice. Therefore, we can understand that the principle of justice followed by Rawls was simply based on Kant's moral philosophy, a kind of "ethical norm" with the meaning of "absolute imperative".
So, under this premise, our understanding of Rawls' political philosophy, which is a statement of moral philosophy given by Rawls, is rooted in Kant.
When we read any of Rawls' works, we will clearly feel that he himself claims to be a student of Kant. However, for other philosophers, it may not necessarily be the case. For example, Peter Singer, an opponent of Rawls' philosophy, follows a contemporary utilitarian approach. Of course, he also has elements of contractualism, but it mainly follows utilitarianism principles since modern philosophy, especially since the late 19th century.
We can see that the philosophical basis for the confrontation between the two philosophies is different, and it is not discussed from the same starting point. However, they all involve Kantian philosophy and use the ideas of Kantian philosophy as a starting point for their ideas, although they go in different directions.
As the ability of pure reason, or as the ability of pure practical reason, according to Kant, he provides a basis, that is, the basis of pure practical reason, according to Kant's understanding, should be defined in this way.
He said that perhaps a non contradictory, more precisely objective principle of causality will be found, which excludes all sensory conditions from the rules of causality. In such a principle, reason no longer originates from something else as the basis for determining causality, but is already contained within the principle itself. Therefore, as pure reason itself, it is practice.
This sentence profoundly reveals the relationship between practical rationality and pure rationality. Any kind of rationality, if it is pure, should fundamentally be practice itself, rather than simply applying rationality to the field of practice as we mentioned earlier. Rationality itself should be practice.
Of course, this reason is pure reason according to Kant's understanding. What does such pure reason mean?
This means that we don't need to use all emotional things as the basis for determining causality.
If we do not take sensory things as the basis of causality, it means that we accept causality itself as a priori condition. We no longer discuss the concept of causality itself, which is a possibility of empirical verification. Instead, we only emphasize a natural or purely rational basis for the existence of causality.
This natural and pure rational basis is based on the concept of causality that we are talking about, which means that the concept of causality itself contains such provisions without the need for external factors to verify them.
So, he said, this principle does not need to be sought or invented, because it has long existed in the rationality of all people and is included in their essence. And this is the principle of morality.
When we consider the rules of practice as a moral principle, although Kant did not explicitly state it here, he clearly only explained one idea, which is the relationship between "finite and infinite".
In other words, when we talk about moral concepts, we are actually discussing the basis for the existence of a finite thing.
Morality is the basis for the existence of finite things, and it can only be applied to those with limited life. It cannot be applied to infinite things. If there are infinite things, morality is not necessary. Morality has no meaning for infinite or eternal things. You cannot talk about morality with God.
Does God have morality? Can we talk about God's morality?
Obviously, it is impossible and unnecessary for us to discuss the morality of God. If we talk about God in this way, it means that we view God as a normal natural person, just like us.
So, for infinite existences, there is no moral problem. Therefore, the concept of morality itself exists in finite existences, which are what we call rational existences. Therefore, the concept of morality is equal to the concept of rational existences.
Only when we truly realize this can we understand why Kant always attributes concepts of causality and morality to the essence of human existence. How can you attribute all of these to the essence of human existence, because humans are inherently finite beings? Therefore, from the perspective of finiteness, this moral essence of human beings is demonstrated, including discussions on human causality.
The concept of causality was originally discussed in nature and does not belong to the field of practice. If we only discuss the concept of causality in the natural environment, it can be accepted because causality exists in nature. Although we can understand the significance of causality as a subjective explanatory activity of humans in various relationships and connections with natural objects, that is, objects.
Although we can understand it as the subject's relationship with external things (objects), which in Kant's view refers to appearances and the connections between the things presented to us, providing a subjective explanatory activity, after all, we can provide such subjective explanations for natural phenomena and then use the concept of causality to encompass all natural things and how they interact with each other. This is what we can provide.
However, for the practical field, how to determine the effectiveness of this causal concept in practice?
How can we ensure that the concept of causality can also be applied in practical concepts or categories. Because for nature, or for the existence of natural things, because such things exist, we give it an explanation that it is not human activity, it is the activity of nature itself. However, humans can attach an explanation to the natural environment, natural objects, or the presentation of a representation.
However, social or practical activities are different, because practical activities are the activities of the subject, not the activities of the object, and they are not some kind of representation presented to us by the activities of the object. So, how can you apply the causal concept used to explain the appearance of object activity to explain the subject activity itself?
This is indeed a big problem, which is how to solve it. If we interpret it as being able to explain the main activity itself, then we must provide an explanation that explains the concept of causality, which precedes our practical activities. If you cannot provide such an explanation, you cannot use this concept.
Because in the field of nature, we can explain it this way, because the concept of causality is a innate concept, a innate category, so we can use the innate category to directly apply it to objects.
However, in the field of practical activities, it is difficult for us to solve this problem, which means it is difficult to apply this innate concept of causality to explain human practical activities. Because practical activities themselves cannot be explained by causality itself.
Therefore, Kant provides a rule here that if we cannot use the concept of causality as it is applied in the natural domain, we can conclude that the concept of causality itself exists in human practice.
So, it is not an explanatory activity, it is a practice that manifests a concept in itself. Therefore, the concept of practice here is people's "moral" activity, and morality itself contains causality.
It is precisely because of this concept that we can understand why Kant confidently used the concept of "pure practical reason" when discussing it. Originally, the term "pure practical reason" corresponded to pure reason. He said, there is a general rationality and a pure rationality. Shouldn't there be a general practical rationality or pure practical rationality here? If we can talk about pure practical rationality, can we talk about it this way?
Of course, when we read Kant, we will find Kant's arguments to explain this pure practical reason, which is entirely to correspond to the concept used in the First Critique. Because there is no pure practical rationality, and the difference between it and general practical rationality is purely for the convenience of discourse, and there is a requirement for a pure practical rationality.
This regulation itself indicates a core concept of Kant, which is that all discussions about reason can only be truly regulated and verified at the practical level. From here, we have a clearer understanding of Kant's concept of practical reason and the relationship between pure reason, as well as his philosophy of practice or morality, and the relationship between a priori philosophy expressed in his Critique of Pure Reason.
Subsequently, we can see that he talked about how such morality can be directly grasped through the concept of causality, or in other words, it can serve as an essential regulation for this person as a rational being. At this moment, we realized that only in the field of practice can we truly reach a state of so-called freedom and obtain true freedom.
