Diametros 54 (2017): 7–29
doi: 10.13153/diam.54.2017.1131

Kant’s Critique of Religion: Epistemic Sources of Secularism

Sorin Baiasu

Abstract. The secular interpretation of Kant is widespread and Kant is viewed as the most prestigious founding father of liberal secularism. At the same time, however, commentators note that Kant’s position on secularism is in fact much more complex, and some go as far as to talk about an ambiguous secularism in his work. This paper defends a refined version of the secular interpretation. According to this refined version, Kant can offer a limited, political secularism on the basis of a simple argument which focuses on the distinct epistemic statuses of political and religious claims; however, the paper argues, a more general secularism is unwarranted on the basis of the same argument. If my argument is correct, then it will account at least in part for the plurality of interpretations. Moreover, any further attempt to show that Kant’s relation to secularism is ambiguous or dismissive should take into consideration the argument from epistemic grounds presented here.

Keywords: Kant’s practical philosophy, religion, secularism, belief/faith, justification, moral knowledge.

1. Introduction

As noted in the literature, the secular interpretation of Kant is widespread and Kant is viewed as the most prestigious founding father of liberal secularism. [1] At the same time, however, commentators note that Kant’s position on secularism is in fact much more complex and some go as far as to talk about an “ambiguous secularism” in his work; [2] however, if correct, the argument of this paper will enable us to identify one possible contributing factor for this complex position, a factor which is epistemic in character. The argument will proceed as follows. After this brief introduction (Section 1), I formulate a simple Kantian epistemic argument in support of secularism (Section 2), with “secularism” understood in a narrow sense.

Next (Section 3), however, I show how the view of Kant as a supporter of this narrow secularism can be questioned, when, together with some recent commentators, we view his account of moral cognition as non-epistemic. This case against the simple Kantian epistemic argument for secularism can in its turn be objected to, since Kant seems clearly to regard practical justification as providing objectively sufficient grounds of assent and, hence, as epistemic. I show, however, that the objection is here raised on the basis of a confusion between two types of conviction which may be produced by our justifications. Hence, the objection to the simple epistemic Kantian argument in support of secularism continues to stand.

Furthermore (Section 4), through focus on the distinction between epistemic and non-epistemic justification and a clarification of what the notion of an objective practical ground can refer to in relation to practical justification and moral knowledge, I show that moral knowledge is indeed justified by epistemic practical justification and I confirm in this way the Kantian argument for secularism. However, a further complication can be raised on the basis of some of Kant’s comments concerning the postulates of practical reason. These comments suggest that religious claims are much closer to moral knowledge than initially suggested. Hence, we have another objection to the simple Kantian epistemic argument for secularism presented in this paper, an objection which needs consideration; this will be the focus in the next section of the paper (Section 5), where the objection will be answered.

Finally, I conclude (Section 6) that the argument in this paper might be sufficient to show what would be wrong in attributing to Kant a broader notion of secularism, especially given his view of the postulates of practical reason. If all these claims are correct, then any further attempt to question Kant’s political secularism would need to take into consideration the argument from epistemic grounds presented here. [3]

2. An Epistemic Argument for Kant’s Secularism

If we assume that secularism is understood, relatively uncontroversially, as the separation of political institutions and representatives from religious arrangements and dignitaries, [4] then secularism seems to be a direct implication of two important claims of Kant’s philosophy. There is, first, the claim that religious statements cannot express knowledge, but are only expressions of faith or belief. As such, they are objectively insufficient statements. There is, secondly, the claim that a standard, which can guide us in the political organisation of a society, is right if it is justifiable to all those affected. This condition of justifiability, however, is an implication of the objective character of the statements which express such standards and which Kant regards as knowledge statements. It follows that any rules and practices which define political institutions and the role of political representatives will need to be objective. Yet, given the first claim (concerning the insufficient objectivity of religious claims), we can conclude that political institutions and representatives will indeed be separate from religious arrangements and dignitaries, which is exactly the secularist position presented above (secularism in the narrow sense [5] ).

The epistemic grounds of this conclusion are provided by Kant’s distinction between knowledge [Wissen], belief/faith [ Glauben] and opinion [Meinen], together with his more subtle distinction between knowledge [Wissen] and cognition [Erkenntnis]. [6] Kant begins the section “On Opinion, Knowledge and Faith” with a characterisation of assent or, literally, holding-for-true [Fürwahrhalten]. Assent is important in this context, since knowledge, belief/faith, and opinion are all forms of assent. When I am of the opinion, or I believe, or know, that X is the case, then I assent to X’s being the case, although with different degrees of confidence. Assent is presented by Kant as “an event in our understanding,” an event that “may rest on objective bases but that also requires subjective causes in the mind of the person who is judging.” [7] Hence, the “subjective causes” are necessary for assent, whereas the objective bases may or may not be present. When I assent to a claim, I may assert it on the basis of sufficient objective evidence, I may be persuaded by it even when sufficient evidence is lacking or I may take the claim to be possible, but neither be convinced by it, nor judge it as objectively justified. The attitude which I display in all these three cases, a positive attitude towards the claim, is the subjective cause of assent. A subjective cause of assent may also be present when I am inventing something arbitrarily, yet, Kant says, this would not amount even to an opinion, since opinion requires “a connection with truth.” [8] Although opinion has a connection with truth, it is an assent consciously insufficient both subjectively and objectively. If the assent is sufficient only subjectively and is regarded as objectively insufficient, then the assent is called faith or belief. Finally, knowledge is the assent that is sufficient both subjectively and objectively. [9]

Moral judgements (including ethical and political claims), Kant says, issue from pure reason, and he thinks they cannot be held as opinion. Thus, since they are not based on experience, but on pure reason, such judgements are necessary and universal, so they can only be knowledge and provide certainty. Thus, for Kant, it is absurd to have opinion in pure mathematics and, he adds, the “same applies to the principles of morality, where one must not venture upon an action on the mere opinion that something is permitted, but must know this to be permitted.” [10] By contrast, judgements that are the result of a “transcendental use of reason” can be neither opinion nor knowledge –“holding an opinion,” Kant says, “is indeed too little, but knowing is again too much.” [11] Reason in its transcendental use goes beyond the limits of sensible intuition – whether a priori or a posteriori – and makes a theoretical claim about things of which we cannot have experience. One such thing is the existence of God, and theism will thus be a position which will therefore be assented to neither as opinion nor as knowledge.

Now, in order for judgements concerning transcendent objects to be classed under the category of belief or faith, Kant says that a practical reference is needed. This practical reference or aim can be either of skill (for contingent and optional purposes) or of morality (for absolutely necessary purposes). [12] Kant distinguishes between pragmatic and necessary faith/belief. The example Kant offers here is that of a physician who must do something for a patient who is in danger. The physician, on the basis of the evidence at her disposal, judges that the patient suffers from a certain illness (more exactly, consumption), but she is not acquainted with the illness so her conclusion is drawn in the absence of anything better. Her belief/faith in the treatment she provides is a pragmatic, contingent one, according to Kant. A pragmatic belief is contingent, but underlies our actual use of the means for certain actions. [13]

In addition, Kant distinguishes between two types of necessity that the conditions which are required for the realisation of a purpose may have. In general, these conditions are hypothetically necessary and subjectively sufficient. Yet, when I focus on certain conditions, because I do not know any other under which the purpose could be attained, they are subjectively sufficient, but only comparatively. By contrast, if I know with certainty that there are no other better conditions under which the purpose could be attained, then their necessity would be subjectively sufficient absolutely and for everyone. [14]

When a claim does not state a hypothetically necessary condition for attaining a certain purpose, the assent to the claim is merely theoretical. Even in this case, Kant adds, we can imagine in a merely theoretical judgement an analogue of practical judgement. We can imagine that, if there were a way of establishing whether the claim was correct or not, we could test our faith/belief in the truth of the claim through a bet. The example Kant offers is that of the existence of extraterrestrial beings. A bet would enable us to establish whether we deal with opinion or with faith/belief. Kant calls the assent to such a merely theoretical judgement doctrinal faith. [15]

Interestingly, Kant says that the existence of God, which is a theoretical judgement, belongs to doctrinal faith. This is interesting, since the existence of God is also the claim of one of the two postulates of practical reason, for which Kant thinks that the justification relies on moral grounds. By contrast, in the case of a doctrinal belief, the assent is not moral, but theoretical. Kant thinks there are theoretical reasons for asserting the existence of God. This is because our cognition of appearances requires the condition of purposive unity, something Kant thinks experience richly illustrates.

He thinks this purposive unity is necessarily made possible by a supreme intelligence, but he takes this unity to be necessary for a “contingent,” although “not unimportant” aim, namely, to have guidance in the investigation of nature. [16] After noting that a similar argument can be formulated about a claim concerning the immortality of the soul, which would be derived from the doctrinal faith in the existence of God, Kant reflects on the status of faith/belief, which he thinks combines an expression of modesty from an objective point of view with one of firmness of confidence from a subjective viewpoint.

Given the support that merely doctrinal faith/belief can obtain and given that speculation sometimes drives one away from this faith/belief and gives the illusion of knowledge, there is something shaky about doctrinal faith/belief. By contrast, moral faith starts from the absolute necessity that something must occur (more exactly, the absolute necessity of complying with the moral law). Here the purpose is no longer merely contingent, but necessary or “inescapably established.” [17] But, Kant says, there is a single condition under which this purpose coheres with the entirety of all purposes and thereby has practical validity – the condition that there is God and a future world, which are the two postulates of practical reason. In addition, I know that no one else is acquainted with other conditions that would lead to the same unity of purposes under the moral law. Since this moral command should also be my maxim, I will inevitably have faith/belief in the existence of God and in a future life. [18] To shake this faith would be to shake my moral principles, “which I cannot renounce without being detestable in my own eyes.” [19]

As a preliminary conclusion, it can be noted that there is a stark difference between moral claims, which are knowledge claims, and religious claims, which are belief or faith claims. Given that belief or faith claims are objectively insufficient forms of assent, they cannot function as a ground for the rules and practices which govern political arrangements and institutional roles, since, as knowledge claims, these are objectively sufficient forms of assent. These rules and practices must therefore have distinct normative origins. Yet, this is exactly the requirement for a secularist organisation of society: the separation of political institutions and representatives from religious arrangements and dignitaries. While the case for secularism in Kant seems easy to be defended, in the next section we will see that complications arise from the same epistemic grounds.

3. Undermining the Case for Kant’s Secularism

I have claimed that one argument in support of Kant’s secularism starts from the difference in the epistemic status of religious and moral claims. Given that, on Kant’s account, a society should be organised politically on the basis of moral principles, the distinct epistemic status of religious and moral claims implies that religious arrangements and dignitaries cannot be seen as linked to political institutions and representatives. On the contrary, given the supposed objective character of moral-political norms, no justification of these norms can be made on the basis of the subjective character of religious claims.

There is one issue, however, which seems to undermine this argument. More recently, in the literature on Kant’s account of justification, it has been claimed that Kant’s practical cognition, including that expressed by moral judgements, is non-epistemic. Given that non-epistemic judgements are expressions of rational beliefs or faith, rather than of knowledge claims, the barrier between political and religious arrangements (namely that between their objectively sufficient and, respectively, insufficient character), as presented in the previous section, would dissolve and the argument for Kant’s political philosophy as secularist would be seriously undermined.

Consider Chignell’s account of justification in Kant. [20] By “justification,” Chignell means “the evaluative concept that specifies conditions under which a propositional attitude is rationally acceptable with a moderate-to-high degree of confidence.” [21] Hence, according to this definition, the object of justification is a propositional attitude, the process of justification consists in determining whether the propositional attitude meets the conditions of rational acceptability, and the status of justified propositional attitude is reached when rational acceptability has a sufficient (moderate to high) degree of confidence.

As we have seen, the propositional attitude that Kant considers is assent [Fürwahrhalten]. If the basis of assent is objectively sufficient, Kant says, then we deal with conviction, which is valid for everyone; Kant contrasts conviction with persuasion, which is an assent with bases only in the particular characteristics of the person who holds it. [22] Truth, Kant notes, rests on agreement with the object. This implies that th e judgments every understanding articulates about an object must be in agreement. Hence, one way to test whether assent is conviction or mere persuasion is through the possibility of communicating the assent and finding it to be valid for every rational being. Subjectively, that is, as an appearance of his own mind, persuasion cannot be distinguished from conviction, Kant claims. But the bases of the assent that are valid for me can be tested on the understanding of the others to see whether they have the same effect on them. If the subjectively particular causes of the judgment are identified, then we expose the status of assent as persuasion. [23] To assert something, Kant says, I must take the judgment I formulate as objectively valid for all and, hence, as conviction. If I know that the judgment is merely valid for me and, hence, as persuasion, I should not try to assert it.

Now, according to Chignell, Kant employs both epistemic and non-epistemic concepts of justification. [24] The epistemic concept refers to assent under conditions that are sufficient for rational acceptability, and when the object of assent is a candidate for knowledge. The non-epistemic notion refers to pragmatic or practical conditions, which guarantee for assent sufficient rational acceptability, but not the status of candidate for knowledge, even if the object of assent is true. The rational acceptance licensed in this way is from a practical point of view.

Epistemic justification refers to objective conditions of rational acceptability for assent that is also a candidate for knowledge. Since Kant refers to these knowledge candidates as convictions, epistemic justification consists of (objective) conditions of rational acceptability of convictions. Non-epistemic justification, by contrast, includes all practical conditions of rational acceptability. I am going to call this type of justification, which consists of practical conditions of rational acceptability, practical justification. However, if we follow Chignell’s distinction between epistemic and non-epistemic justification, the implication is that practical justification is non-epistemic.

But, if practical justification is non-epistemic, then Kant’s practical or moral epistemology could not include a notion of justification, since paradoxically, as part of a practical epistemology, this notion of justification would have to be practical, in which case it could no longer be epistemic and, hence, part of an epistemology. And a practical epistemology without a notion of justification would be a strange account of practical knowledge. I have dealt with this problem elsewhere. [25] My main concern here is with one implication of this distinction between epistemic and non-epistemic justification and of the non-epistemic character of practical justification. For, if practical justification in general, including that of moral norms, is non-epistemic, then the worry is that the distinction drawn earlier between the normative status of moral claims and that of religious claims is not as clear as presented, and the simple case for Kant’s secularism begins to become shaky.

One possible reply to this objection is that, respectively, the epistemic or non-epistemic character of the justification of theoretical and practical claims in Kant is not what is crucial; what is crucial is the extent to which the non-epistemic justification of moral norms has an objectively sufficient force, in contrast to the objectively insufficient character of the justification of religious claims. But, in order for this reply to work, we would need to investigate further what is specific for epistemic justification and whether classing practical justification as non-epistemic deprives it of its objectively sufficient character.

Before examining further the distinction between epistemic and non-epistemic justification, let us consider one argument in support of the reply I have just formulated, namely, that the practical justification of moral norms, although non-epistemic, has nevertheless an objectively sufficient force. Recall that, according to Kant, if the basis of assent is objectively sufficient, then we deal with conviction, which is valid for everyone; moreover, conviction is distinct from persuasion, which is an assent with bases only in the particular characteristics of the person who holds it. [26] Because Kant does talk about conviction in relation to practical justification, it follows that the basis of assent provided by practical justification can be objectively sufficient. The distinction between moral norms and religious claims would in this way be easily vindicated, and the attempt to undermine the argument offered in this paper for Kant’s secularism would be rejected.

For instance, in the third Critique, in relation to a certain type of proof, Kant says:

[...] if it is based on a practical principle of reason (which therefore holds universally and necessarily), then it may indeed claim to convince sufficiently from a pure practical point of view. [27]

Hence, if that which gives rise to conviction is practical justification, then, given that conviction requires objectively sufficient grounds, perhaps we can maintain the argument that religious claims cannot ground moral claims, since the latter, unlike the former, are based on objectively sufficient grounds.

In response, one can first point to the fact that Kant’s discussion of conviction in the First Critique only suggests that typically a conviction is a candidate for the status of knowledge. The implication then is that some convictions need not be candidates for the status of knowledge. Hence, the suggestion is that, although one may talk about convictions in relation to practical cognition, those convictions are not candidates to knowledge and, hence, are not objectively sufficient.

The implication, then, is to pay attention to Kant’s distinction between two types of conviction, only one of which is a candidate for the status of knowledge. Reference here can be made quite easily to Kant’s Lectures on Logic, in particular the Jäsche Logic:

[…] we can now draw the universal result that all our conviction is thus either logical or practical. When we know, namely, that we are free of all subjective grounds and yet the holding-to-be-true [assent—Fürwahrhaltung] is sufficient, then we are convinced, and in fact logically convinced, or convinced on objective grounds (the object is certain).

Complete holding-to-be-true [assent] on subjective grounds, which in a practical relation hold just as much as objective grounds, is also conviction, though not logical but rather practical conviction (I am certain). And this practical conviction, or this moral belief of reason [moralische Vernunftglaube], is often firmer than all knowledge. With knowledge one still listens to opposed grounds, but not with belief [Glaube], because here it does not depend on objective grounds but on the moral interest of the subject. [28]

According to this distinction, logical conviction is conviction based on objective grounds, which are sufficient without the contribution of subjective grounds. Practical conviction, by contrast, is based on subjective grounds; one is convinced (in a practical relation) that something must be the case as a means to a specific end. Consequently, one could explain how Kant can talk about conviction in relation to practical justification: what he has in mind is practical, not logical conviction. Yet, if epistemic justification is given by logical conviction which is, thus, not mere conviction, but also a candidate for knowledge, then practical justification is not epistemic, although it may well ground conviction (that is, practical conviction). Consequently, epistemic justification concerns logical conviction and sometimes turns such conviction into knowledge if that which the conviction is about (the claim or assertion) is true.

In this way, the argument in support of the reply is rejected: practical conviction, although associated by Kant with the justification of practical principles, does not provide objectively sufficient grounds. Moreover, we seem to be able to reject the reply itself, since non-epistemic justification does not seem to provide objectively sufficient moral bases for practical judgements; if all this is correct, then we are back to the initial objection to the case for Kant’s secularism. In fact, however, the reply cannot be rejected so quickly. What we have actually shown is that the non-epistemic justification which produces practical conviction cannot obtain the status of a candidate for knowledge. What we need to determine at this point is whether the difference between epistemic and non-epistemic justification in general (and not merely that which affords practical conviction) deprives practical justification of the ability to provide support which is objectively sufficient. Only then can we say that practical justification in general is non-epistemic. So the next step is to investigate in more detail the distinction between epistemic and non-epistemic justification.

Kant specifies that assent may rest on objective bases, but also requires subjective causes in the mind of the person who is judging. [29] As I have already mentioned above, this means that, even when epistemic justification can show that assent is objectively sufficient or sufficient on objective grounds, we still need subjective causes in the mind of the person who has the assent.

According to Chignell, one way to understand the subjective cause for assent when we deal with knowledge is as recognition that assent is based on objectively sufficient grounds. [30] Subjectively sufficient assent is then defined through a series of conditions: that such assent need not imply reflection, that it should not involve an infinite regress (due to the fact that recognition can be understood as involving subjective assent), that it should make conceptual room for persuasion (subjectively sufficient assent where the grounds for assent may be bad), and that it should avoid a case where assent is not well founded. Since subjectively sufficient assent depends on objectively sufficient assent (since subjectively sufficient assent includes the recognition that assent is based on sufficient objective grounds), we need both notions.

These two notions (call them OS and SS 1) constitute epistemic assent, which is then contrasted with non-epistemic assent. Recall that, since my aim here is to examine the extent to which practical justification can be epistemic in character and, hence, involve, for the case of moral standards, objectively sufficient grounds, one important step is precisely to examine the difference between these notions of epistemic and non-epistemic assent. Specific for non-epistemic assent is that it cannot be objectively sufficient, since this would place it under the notion of objectively sufficient assent, which has an epistemic character. For this reason, we are going to find under the category of non-epistemic assent only subjectively sufficient grounds of assent. Chignell identifies two such notions (call them SS 2 and SS 3), which are analogous to the epistemic ones. One of these notions (SS 2) concerns subjectively sufficient assent in virtue of a non-epistemic merit which the claim assented to has for a person, a merit which is a subjectively sufficient ground. The second notion (SS 3) is similar, but it involves recognition that the non-epistemic merit the claim assented to has is sufficient for the assent. [31]

According to Chignell, knowledge requires the first two notions of assent, rational belief requires the third and reflective belief requires the fourth and final one. If we look at the distinction between epistemic and non-epistemic assent, which is the starting point of my discussion in this section, we can see that the objective grounds of assent give the mark of the epistemic. Whether epistemic or non-epistemic, assent can be subjectively sufficient, but the difference between the second notion of subjectively sufficient assent, which refers to epistemic assent, and the third and fourth, which refer to non-epistemic assent, is that the agent would regard the support for assent as an objective ground in the former case and as having some (subjective) merit in the latter cases (for instance, the ground of assent could be that the judgement assented to furthers our moral interest).

This seems to suggest that the argument for Kant’s secularism presented in Section 1 is now clearly undermined. Thus, I have argued that the way in which Kant’s limited secularism can be defended is by making clear the distinct epistemic statuses of moral standards and religious claims. Yet, given that both these types of claim are considered as requiring practical justification and given that practical justification seems to be non-epistemic, the distinction is weakened and the initial case for political secularism in Kant is undermined. In the next section, however, the distinction between objective ground and subjective merit will be investigated in more detail and a defence of the case for secularism will be provided.

4. Epistemic Practical Justification

The best way to understand the distinction between objective ground and subjective merit for assent is to clarify the notion of objective ground. [32] We can begin with a quote from the Blomberg Logic, which provides a definition of ground as that from which something can be cognized. [33] We can then look at Kant’s First Critique for a definition of objective ground: that which provides reliable information about the constitution of the object or state of affairs described by some proposition. [34] This is in line with what Kant says in the Jäsche Logic, as already quoted above: unlike knowledge, belief [Glaube] “does not depend on objective grounds but on the moral interest of the subject.” [35] Knowledge [Wissen] is here firmly associated with the idea of objective ground, whereas faith/belief [Glaube] – with moral interests. This, however, seems to be in tension with other claims Kant makes in the same work and which are also echoed elsewhere.

For instance, in discussing the assent presupposed by faith/belief [Glauben], he excludes as possible objects of faith/belief those “objects of cognition by reason (cognition a priori), whether theoretical, e.g., in mathematics and metaphysics, or practical, in morals.” [36] This suggests that we can have objective grounds in the case of practical philosophy: insofar as a ground is that from which something can be cognized, practical cognition a priori will need objective grounds; insofar as an objective ground provides reliable information about the constitution of an object, the grounds we have in morality will have to provide reliable information about the constitution of the objects cognized by practical reason.

Once we accept that we can have knowledge in the practical domain, we also need to accept that practical justification is part of the category of epistemic justification or that of the ground of epistemic assent. In fact, in the Jäsche Logic, among others, Kant explicitly says that we do have practical knowledge: “Nothing could be more ridiculous than, e.g., only to opine in mathematics. Here, as in metaphysics and in morals, the rule is either to know or not to know.” [37]

The question is, then, how it is possible to have objective grounds in practical philosophy. The problem in practical philosophy is that our claims are about what ought to be the case, rather than about what is the case. Since what is the case may not be what ought to be the case (say, the action I am witnessing is not the action that ought to have been performed), we cannot derive our practical claims from our theoretical claims. If so, our practical claims are a priori and, more exactly, they are claims formulated by practical reason. But a priori claims formulated by reason usually refer to objects of which we can have no knowledge. This is the case for the claims concerning the existence of God or the immortality of the soul, which are theoretical claims which refer to the unconditioned and, hence, which we can think only with the help of the a priori ideas of reason. Yet, given that our experience is only of conditioned aspects of the world, we cannot know whether there is anything that corresponds to these ideas. As Kant puts it, “it is intrinsically impossible to exhibit rational ideas in intuition, and hence also intrinsically impossible to prove theoretically that they are possible.” [38]

There is however one exception: the idea of freedom. Kant makes this claim in various places, but I will focus on what he says in the third Critique. In “On What Kind of Assent Results from a Practical Faith,” he starts by defining matters of fact as “objects of concepts whose objective reality can be proved.” [39] He specifies that proving the objective reality of concepts can be done either by reason ( a priori) or by experience (a posteriori), and, in the former case, either from theoretical or from practical data of reason. At any rate, Kant adds, this proof will be provided by an intuition corresponding to the data.

Now, the reality of the idea of freedom is established through practical laws of pure reason and, if we act on these laws, we can establish the reality of the idea in the actual acts and, hence, in experience. This, Kant says, is possible through the concept of causality, which we think in the idea of freedom. Given the concept of causality and the effects freedom seems to have in nature in the form of moral actions, we can conclude that freedom has objective reality. Moreover, in this way, freedom expands reason beyond the bounds within which any concept of nature would have to remain confined. In other words, nature and our knowledge of nature are related to sensibility; although freedom cannot be the object of sensible intuition, its effects (moral, free actions) are objects of experience. [40]

But if the object corresponding to the concept of freedom has objective reality, then claims about this object can be supported with reliable information about the constitution of this object. Yet, this is precisely the idea of an objective ground, which, as we have seen, is the mark of the epistemic. Of course, there are differences between objects of experience and the object corresponding to the idea of freedom, but there are also significant similarities. For instance, according to Kant, we know the object corresponding to the concept of freedom by thinking of it as a cause, and determining it both through its effects (which are objects of experience) and through the laws of this causality (moral principles, which regulate the effects of freedom).

Some entities in the sciences, initially hypothesized to account for certain phenomena, may come to be known through their effects and through the laws which regulate the occurrence of those effects, although they may not be perceivable either directly or indirectly through the senses. To be sure, as I said, there are also significant differences. For instance, the reasons why certain causes in the sciences may not be directly or indirectly perceivable through the senses is distinct from the reason why the object corresponding to the idea of freedom is not. In the former case, we may deal with entities that are too small to be directly perceivable, and the instruments of observation may affect their indirect observation. In the latter case, the object is by definition beyond the conditions which make sensibility and perceiveability possible. [41]

Although in the case of moral actions Kant says that we can perceive them, what we can perceive are those features which may also characterize evil or morally indifferent actions. Imagine, for instance, an evil person who performs actions that conform to moral standards in order to get the others to trust him. Imagine also a person who performs by accident an action that conforms to the relevant moral standard. The actions we perceive are indistinguishable from the same actions performed out of duty by a moral agent, and yet the performing agent may be evil. The reason why we deal with knowledge and epistemic justification in both cases, in spite of the dissimilarity between moral judgements, which are practical, and theoretical cognition, is given by the modality involved in their deontic status: moral judgements can represent knowledge, since they refer to statements of what ought to be the case; unlike theoretical knowledge, which asserts what is the case (and, for a priori knowledge, what necessarily is the case), moral knowledge states our obligations.

Obligations constitute the objects of practical reason – the good and the evil (which are, of course, instantiated by particular good and evil actions). The objective grounds of practical knowledge do indeed provide reliable information about the constitution of the objects or states of affairs described by practical propositions. This is because practical propositions are about what ought to be the case or what ought not to be the case, and their justification is provided a priori by pure practical reason. Because they describe potentially actual good or evil actions, which are the objects of practical reason, and because pure practical reason provides reliable information (through the moral law and its application to particular cases) about the constitution of these objects, our practical claims can be regarded as offering a form of assent which is objectively and subjectively sufficient, that is, (practical) knowledge.

It follows that, if the mark of the epistemic justification is that objective grounds constitute it, then at least certain types of practical justification are epistemic. Specifically, as I have argued so far, justification of moral principles is epistemic, since moral principles are items of practical knowledge as laws of the causality of freedom. If we contrast the objectively sufficient claims expressed by moral principles with the objectively insufficient ones of religious statements, then we have a clear argument for Kant’s political secularism. For political institutions and roles are based on juridical rules, which, for Kant are moral in character and, hence, are objectively sufficient. There is, however, one further complication, which arises when we consider Kant’s argument that not only claims concerning freedom are epistemic, but even claims related to the other two ideas of reasons, that of God and of the soul. If religious claims also turn out to be epistemic, then we are back to the worry that the epistemic statuses of moral norms and religious claims are not sufficiently distinct to provide an argument for limited secularism. Nevertheless, before concluding my argument, in the next section I will show why the nature of Kant’s argument here makes it the case that his political secularism is not thereby challenged. This will also make clearer why the literature on this aspect of Kant’s philosophy ends up with conclusions which are in tension, if not directly contradictory.

5. An Extension of Pure Reason

Kant famously states that the existence of God and the immortality of the soul (the postulates of practical reason) are theoretical claims, which cannot be considered knowledge, but are matters of faith or belief. In the remainder of this section I would like to argue that, even if we focus on practical postulates, it can still be demonstrated that the grounds provided in support of the postulates should be regarded as constitutive of epistemic justification. Nevertheless, I will conclude that this is not a challenge for the argument concerning Kant’s political secularism, but illustrates the difficulties of interpreting Kant’s position in relation to secularism and points to a possible factor which prompts the diversity of positions in the literature.

I would like to go back to the second Critique, to Chapter VII of the “Dialectic of Pure Practical Reason.” This chapter examines “[h]ow it is possible to think an expansion of pure reason for a practical aim without thereby also expanding its cognition as speculative.” [42] At the beginning of this chapter, Kant explains how pure cognition can be expanded practically: what we need, he says, is an a priori aim or purpose that is presented as practically necessary independently from all theoretical principles. This purpose, he continues, is possible only if three theoretical concepts are presupposed as possible, although no intuition can correspond to them (since they are ideas of pure reason) and, hence, no objective reality can be attributed to them by following the “theoretical path.” [43] These three ideas (freedom, immortality, and God) are postulated as possible through the practical law, which presents the purpose as practically necessary.

I take it, however, that the crucial claim Kant makes is the following:

By this, then, the theoretical cognition of pure reason does of course acquire an increase, which however consists merely in this: that those concepts which are otherwise problematic (merely thinkable), are now assertorically declared to be concepts to which objects actually belong, because practical reason unavoidably requires the existence of these for the possibility of its object […], which moreover is absolutely necessary practically, and theoretical reason is thereby entitled to presuppose them. [44]

According to Kant’s argument here, the justification of the postulates of practical reason does not merely entitle us to a moral faith or belief in immortality and the existence of God, we are also entitled to limited theoretical cognition that the concepts corresponding to the ideas of reason are not merely problematic (thinkable), but also assertoric (declarable as concepts to which objects actually belong). It is this that may seem to challenge the initial argument for secularism presented in this paper, since it suggests that some religious claims may also be objectively sufficient.

Nevertheless, Kant hastens to add that we cannot make use of this expansion of the theoretical cognition of pure reason to obtain “an expansion of speculation, i.e., no positive use can now be made of it for a theoretical aim.” [45] Such a use would allow us to say something about the objects that actually belong to these concepts, and not simply to assert that objects do belong to the ideas of reason. Yet, Kant says, we are not allowed to expand our cognition in this way, but only with regard to the practical use of pure reason. In the same way in which Kant claimed in the Third Critique that the idea of freedom can acquire objective reality, he claims it for immortality and God. [46]

This discussion is in fact useful also as a qualification of the brief examination of the objective reality of freedom presented above. For Kant now says that the suprasensible objects that correspond to the ideas of reason cannot be further cognized even with the introduction of the practical necessary purpose determined by the moral law. 21 For what is missing for the expansion of pure cognition in the theoretical direction is an intuition of the objects corresponding to the ideas of reason:

Theoretical cognition, not indeed of these objects but of reason as such, has thereby been expanded insofar as through the practical postulates those ideas have after all been given objects, because a merely problematic thought has thereby for the first time acquired objective reality. This was, therefore, no expansion of the cognition of given suprasensible objects, but still an expansion of theoretical reason and of its cognition with regard to the suprasensible as such, insofar as theoretical reason was compelled to grant that there are such objects, even though it could not determine them more closely and hence could not itself expand this cognition of the objects (which have now been given to it on a practical basis and also only for practical use). [47]

This long quotation clarifies some aspects of the status of the claims Kant makes. It seems that it is possible to distinguish between the following three categories of claims. First, there are claims about what there is (and these are theoretical claims), which are made with a view to a theoretical aim (for instance, that of creating a unified system of knowledge). Kant is quite clear that we are not entitled to such claims about the objects corresponding to the ideas of reason – all we obtain is doctrinal belief/faith. Second, there are those theoretical claims which are necessary conditions for the possibility of a practical purpose. This is the case of the claims made by the postulates, but, again, Kant says we are entitled only to moral faith or belief and not to knowledge. Finally, there are practical claims, which are derived from the practical necessity of the moral law and which lead us to knowledge about what is right and what is wrong. Yet, this knowledge is not acquired with a view to a theoretical, but to a practical aim.

Now, the expansion of theoretical knowledge into the suprasensible realm that Kant talks about is nothing but an implication of the moral belief or faith obtained when theoretical claims (especially those of the postulates) are vindicated as necessary conditions for moral purposes. The moral belief in the postulates turn the concepts corresponding to the ideas of reason from problematic notions to assertoric ones, but without any knowledge of the content of these concepts. Since in this way we expand theoretical cognition and since we do this on the basis of the justification of our entitlement to belief or faith in the practical postulates, this justification has also an indirect epistemic character. Hence, there is a sense in which even the justification of moral faith or belief has an indirect epistemic character.

This implies that epistemic justification includes reference not only to theoretical claims where access to the corresponding objects through sensible intuition is in principle possible or to practical claims where access to the corresponding objects is possible through reason’s ideas of good and evil, but includes also reference to claims concerning the objects corresponding to the ideas of reason, but claims made with a practical purpose in view. Yet, although this may seem to undermine again the case for Kant’s political secularism, it becomes clear that the initial argument still holds. This is because the epistemic character of any religious claims concerning the existence of God or immortality of the soul has no other source of validity than that of the postulates and our assent to the postulates is moral faith/belief, rather than knowledge.

6. Conclusion

The Kantian argument for narrow secularism presented in this paper relies on the distinct epistemic statuses of moral and religious claims. According to Kant, the juridical principles on the basis of which a state is organised are distinct from ethical principles, but are nevertheless together with ethical principles part of moral theory. As such, these claims have objectively sufficient grounds, which justify them as practical knowledge. By contrast, religious claims are theoretical claims whose objects go beyond our experience and cannot therefore be justified objectively. They are justified on the basis of subjectively sufficient grounds and represent the object of belief or faith.

This Kantian argument for secularism was examined in this paper through a discussion of two main objections. First, we have considered one interpretation in the literature according to which the justification of practical claims is non-epistemic and, hence, cannot provide objectively sufficient ground for practical claims. Secondly, we have discussed the view according to which, on Kant’s account, claims concerning the existence of God and the immortality of the soul are epistemic in a limited sense. Hence, even granting that moral claims can be justified as knowledge claims, it seems that on Kant’s account religious claims can be similarly justified too. As a result, the distinction between the distinct epistemic statuses of legal principles and religious claims is undermined and cannot support secularism even in the narrow form discussed here.

After considering a weaker response which made appeal to the notion of conviction, the first objection was refuted by an investigation into Kant’s view of an objective ground of justification; the conclusion was that moral claims can have objectively sufficient grounds of justification and, therefore, are indeed forms of knowledge. I have then responded to the second objection by presenting the very limited sense in which Kant thinks some religious claims can be epistemically justified and have therefore a cognitive status. The conclusion was, however, that this limited sense only emphasised more clearly the different epistemic character of juridical principles and religious claims.

One final note on another possible objection: [48] in the third paragraph of Religion, Kant claims that morality inevitably leads to religion; from the perspective of my distinction between the epistemic statuses of moral and religious claims this seems impossible. I only note here, having to postpone any further discussion for another occasion, that a transition from moral claims (which are both objectively and subjectively sufficient) to religious claims (which are only subjectively sufficient) seems unproblematic and need not go against my claim that the two types of claims have distinct epistemic statuses. A detailed discussion of this issue goes beyond the scope of this paper, but one last note can be usefully made here: any discussion of this Kantian claim in the third paragraph of Religion would need to be read together with Kant’s claims at the beginning of Religion, claims according to which on its own behalf morality in no way needs religion. [49]

It should be clear now that any further attempt to show that Kant’s relation to secularism is ambiguous or dismissive should take into consideration the argument from epistemic grounds presented here. [50]


  1. Although acknowledging that Kant was a believer, some commentators note “that the consequences – both intended and unintended – of Kant's critical philosophy have had the greatest philosophical influence on making unbelief a legitimate alternative to faith in a transcendent God.” Bernstein (2009): 1035. They also remark that “[t]his attempt to privatize religion […] emerged out of a series of political and philosophical attempts to manage and moderate sectarianism in European politics. No philosopher was more committed to this effort than Immanuel Kant.” Hurd (2008): 25. Finally, they note: “in Genealogies of Religion, Asad […] discussed Immanuel Kant’s work on religion. […] Asad’s tracing of the Kantian-secular understanding of ‘religion’ is connected to his critique of secularism as a norm for today’s world.” Jansen (2017): 379.
  2. “Though Kant may be considered the most prestigious Father of liberal secularism, my interpretation of his ideas about the relationships between religion and politics is that they can be profitably employed to contrast precisely that widespread form of contemporary Western secularism, which maintains that religion is a private matter that should play no role in the design of political institutions and the adoption of political decisions.” Pera (2012): 546; “Although the secular interpretation of Kant is widespread, it is belied by a significant share of the Critical corpus. Not only do we find powerful defenses of religious belief in all three Critiques, but a considerable share of Kant's work in the 1790s is devoted to the positive side of his philosophy of religion.” Pasternack, Rossi (2014). Chapter 2 of Emmet Kennedy’s book, Secularism and Its Opponents from Augustine to Solzhenitsyn, is titled “Immanuel Kant’s Ambiguous Secularism.” Kennedy (2006): 131.
  3. I agree with Tomaszewska’s argument (“Kant almost dilutes the contents of religious belief in an ethical doctrine which he projects to be endorseable by everyone. This, to my mind, takes him closer to some ‘radical’ tendencies in the Enlightenment than many commentators would be inclined to admit”) [Tomaszewska (2017): 125], but I think the crucial element in her claim is the “almost”: if my argument in this paper is right, then there is a fundamental difference between the epistemic statuses of religious and ethical claims in Kant, and this difference is the ground of the limited, political secularism, which is the focus of this paper.
  4. I think this position can be specified further in an uncontroversial way, since this separation marks in fact the lack of a relation of dependence: political institutions and representatives are independent from religious arrangements and dignitaries. A non-secular, religious state is one where the dependence holds to some extent at least.
  5. A broader secularism will assert this link between institutions and religious arrangements beyond the political sphere. At the extreme, a communist state, such as the Soviet Union, would try to exclude religion from all aspects of society, including the social, cultural, and economic ones.
  6. For certain aspects of this paper, I draw on my Baiasu (2013).
  7. KrV, A 820/B 848: “eine Begebenheit in unserem Verstande”; “auf objektive Gründen beruhen mag, aber auch subjektive Ursachen im Gemüte dessen, der da urteilt, erfordert.” In citing Kant’s works the abbreviations listed below will be used. Pagination references in the text and footnotes are to the volume and page number in the German edition of Kant’s works (1900–). References to the Critique of Pure Reason (KrV) follow the A (first edition), B (second edition) convention. Translations used are listed in the bibliography.
  8. KrV, A 822/B 850: “eine Verknüpfung mit Wahrheit.”
  9. Ibidem.
  10. KrV, A 823/B 851: “Eben so ist es mit den Grundsätzen der Sittlichkeit bewandt, da man nicht auf bloße Meinung, daß etwas erlaubt sei, eine Handlung wagen darf, sondern dieses wissen muß.”
  11. Ibidem: “Im transzendentalen Gebrauche der Vernunft ist dagegen Meinen freilich zu wenig, aber Wissen auch zu viel.”
  12. Ibidem. See also the Conclusion to Rechtslehre, MS RL, AA 6:354–355.
  13. KrV, A 824/B 852.
  14. KrV, A 823-824/B 851–852.
  15. KrV, A 825/B 854.
  16. KrV, A 826/B 854: “zufälligen […] unerheblichen.”
  17. KrV, A 828/B 856: “unumgänglich festgestellt.”
  18. The postulates of practical reason are presented in detail in Kant’s Critique of Practical Reason; the argumentative strategy there seems to be the following (although there are debates as to whether it works, especially given Kant’s idea of a fact of reason): the moral law can be derived from the fact of reason; yet, the moral law and the virtuous actions which are performed when acting on the moral law are only part of the highest-complete good; the other part is happiness, which must be viewed as part of the highest good as in accordance with virtue. Kant thinks that there are two obstacles which make difficult our realisation of the highest-complete good: time for our moral improvement and power to distribute happiness in accordance with virtue. The postulates of the existence of God and immortality of the soul are supposed to make possible the highest-complete good and, hence, to preserve my moral principles unshaken (at least with respect to their possible realisation).
  19. KrV, A 828/B 856: “denen ich nicht entsagen kann, ohne in meinen eigenen Augen verabscheuungswürdig zu sein.”
  20. Chignell (2007).
  21. Ibidem: 33.
  22. KrV, A 820/B 848.
  23. KrV, A 821/B 849.
  24. Chignell (2007): 34.
  25. Baiasu (2013).
  26. KrV, A 820/B 848.
  27. KU, AA 5:463: “legt er aber ein praktisches Vernunftprinzip zum Grunde (welches mithin allgemein und notwendig gilt), so darf er wohl auf eine, in reiner praktischer Absicht hinreichende […] Überzeugung Anspruch machen.”
  28. Log, AA 9:72: “können wir nun das allgemeine Resultat ziehen: daß also alle unsre Überzeugung entweder logisch oder praktisch sei. – Nämlich wenn wir wissen, daß wir frei sind von allen subjektiven Gründen und doch das Fürwahrhalten zureichend ist, so sind wir überzeugt und zwar logisch oder aus objektiven Gründen überzeugt (das Objekt ist gewiß). Das komplette Fürwahrhalten aus subjektiven Gründen, die in praktischer Beziehung so viel als objektive gelten, ist aber aucch Überzeugung, nur nicht logische, sondern praktische (ich bin gewiß). Und diese praktische Überzeugung oder dieser moralischer Vernunftglaube ist oft fester als alles Wissen. Beim wissen hört man noch auf Gegengründe, aber beim Glauben nicht; weil es hierbei nicht auf objektive Gründe, sondern aus das moralische Interesse des Subjekts ankommt.”
  29. KrV, A 820/B 848.
  30. Chignell (2007): 44.
  31. For the full details, see Chignell (2007): 46–56; for discussion, see Baiasu (2013): 34–36.
  32. Chignell discusses this in his 2007 text on page 39.
  33. V-Lo/Blomberg, AA 24:42.
  34. KrV, A 821/B 849.
  35. Log, AA 9:72: “es hierbei nicht auf objective Gründe, sondern aus das moralische Interesse des Subjekts ankommt.”
  36. Log, AA 9:68: “auch keine Objekte des Vernunfterkenntnisses (Erkenntnisses a apriori), weder des theoretischen, z. B. in der Mathematik und Metaphysik; noch des praktischen in der Moral”; see also KrV, A 822–823/B 850–851.
  37. Log, AA 9:67: “Auch könnte in der Tat nichts lächerlicher sein, als z. B. in der Mathematik nur zu Meinen. Hier, so wie in der Metaphysik und Moral, gilt es: entweder zu wissen oder nicht zu wissen”; see also KrV, A 823/B 851.
  38. KU, AA 5:468: “die [eine Vernunftidee] sich an keiner Darstellung in der Anschauung, mithin auch keiner theoretischen Beweises ihre Möglichkeit, fähig ist.”
  39. Ibidem: “Gegenstände für Begriffe, deren objektive Realität […] bewiesen werden kann.”
  40. KU, AA 5:474.
  41. This is mainly related to Kant’s principle of opacity of our motivation; if freedom is manifested through actions motivated by respect for the moral law, given that we can never be sure of the nature of our motivations (whether they were indeed ethically worthy motivations promoted only by respect or they were motivations provided by various contingent interests and inclinations – see GMS, AA 4:407), we can never be sure whether our actions are free or not. But this is not a major problem here, since what we need is not some evidence of free actions, but of valid moral standards.
  42. KpV, AA 5:134–141: “Wie eine Erweiterung der reinen Vernunft, in praktischer Absicht, ohne damit ihr Erkenntnis, als spekulativ, zugleich zu erweitern, zu denken möglich sei?”
  43. KpV, AA 5:134: “theoretischen Wege.”
  44. Ibidem: “wodurch denn die theoretische Erkenntnis der reinen Vernunft allerdings einen Zuwachs bekommt, der aber bloß darin besteht, daß jene für sie sonst problematische (bloß denkbare) Begriffe jetzt assertorisch für solche erklärt werden, denen wirklich Objekte zukommen, weil praktische Vernunft die Existenz derselben zur Möglichkeit ihres, und zwar praktisch-schlechthin notwendigen, Objekts […] unvermeidlich bedarf, und die theoretische dadurch berechtigt wird, sie vorauszusetzen.”
  45. Ibidem: “keine Erweiterung der Spekulation, d.i. um in theoretischer Absicht nunmehr einen positiven Gebrauch davon zu machen.”
  46. KpV, AA 5:135.
  47. Ibidem: “Aber dennoch ward das theoretische Erkenntnis, zwar nicht dieser Objekte, aber der Vernunft überhaupt, dadurch sofern erweitert, daß durch die praktischen Postulate jenen Ideen doch Objekte gegeben wurden, indem ein bloß problematischer Gedanke dadurch allererst objective Realität bekam. Also war es keine Erweiterung der Erkenntnis von gegebenen übersinnlichen Gegenständen, aber doch eine Erweiterung der theoretischen Vernunft und der Erkenntnis derselben in Ansehung des Übersinnlichen überhaupt, so fern als sie genötigt wurde, daß es solche Gegenstände gebe, einzuräumen, ohne sie doch näher bestimmen, mithin dieses Erkenntnis von den Objekten (die ihr nunmehr aus praktischem Grunde, und auch nur zum praktischen Gebrauche, gegeben worden).”
  48. I am grateful to one of the referees for this paper for raising this point.
  49. For a good discussion, see Hare (2013).
  50. Acknowledgements: An early version of this paper was presented to the Colloquium on Enlightenment and Secularism at the Department of the History of Philosophy, Jagiellonian University in Kraków. I am grateful to participants for the useful comments and discussion. I would like to thank The Enlightenment Ideas of Freedom of Thought and Conscience, and Contemporary Secularism grant (no: UMO-2014/15/D/HS1/02751), funded by the National Science Centre in Poland, and in particular the project’s PI, Anna Tomaszewska, for financial support in relation to the participation to the event. I am grateful to two anonymous referees for their feedback. In reply to one of their comments, I mention that I take the term “critique” in the title in the Kantian Critical sense, that is, as an exploration of the necessary conditions and, hence, epistemic limits of religious claims. The discussion of the epistemic sources of secularism is a particular aspect of Kant’s critique (in the sense specified) of religion.


  1. Baiasu S. (2013), “Kant’s Rechtfertigung and the Epistemic Status of Practical Justification,” [in:] Kant on Practical Justification. Interpretive Essays, M. Timmons, S. Baiasu (eds.), Oxford University Press, New York.
  2. Bernstein R.J. (2009), “The Secular-Religious Divide: Kant’s Legacy,” Social Research 76 (4): 1035–1048.
  3. Chignell A. (2007), “Kant’s Concepts of Justification,” Noûs 41 (1): 33–63.
  4. Hare J. (2013), “The Place of Kant’s Theism in His Moral Philosophy,” [in:] Kant on Practical Justification. Interpretive Essays, M. Timmons, S. Baiasu (eds.), Oxford University Press, New York.
  5. Hurd E.S. (2008), The Politics of Secularism in International Relations, Princeton University Press, Princeton and Oxford.
  6. Jansen Y. (2017), “Beyond Comparing Secularisms: A Critique of Religio-Secularism,” [in:] The Oxford Handbook of Secularism, P. Zuckerman, J.R. Shook (eds.), Oxford University Press, Oxford.
  7. Kant I. (1900–), Kants gesammelte Schriften, Edited by the Königliche Preußische Akademie der Wissenschaften, subsequently Deutsche, now Berlin-Brandenburg Akademie der Wissenschaften (originally under the editorship of Wilhelm Dilthey), Georg Reimer, subsequently Walter de Gruyter, Berlin.
  8. Kant I. (1987), Critique of Judgment, trans. W.S. Pluhar, Hackett, Indianapolis. [KU]
  9. Kant I. (1992), Lectures on Logic, trans. and ed. J.M. Young, Cambridge University Press, Cambridge. [Log and V-Lo/Blomberg]
  10. Kant I. (1996a), Critique of Pure Reason, trans. W.S. Pluhar, Hackett, Indianapolis. [KrV]
  11. Kant I. (1996b), “Groundwork of The Metaphysics of Morals,” [in:] I. Kant, Practical Philosophy, trans. and ed. M.J. Gregor, Cambridge University Press, Cambridge: 37–108. [GMS]
  12. Kant I. (1996c), “The Metaphysics of Morals,” [in:] I. Kant, Practical Philosophy, trans. and ed. M.J. Gregor, Cambridge University Press, Cambridge: 353–604. [MS RL]
  13. Kant I. (1996d), “Religion within the Boundaries of Mere Reason,” [in:] I. Kant, Religion and Rational Theology, trans. and ed. A.W. Wood, G. di Giovanni, Cambridge University Press, Cambridge: 39–215. [RGV]
  14. Kant I. (2002), Critique of Practical Reason, trans. W.S. Pluhar, Hackett, Indianapolis. [KpV]
  15. Kennedy E. (2006), Secularism and Its Opponents from Augustine to Solzhenitsyn, Palgrave Macmillan, Basingstoke and New York.
  16. Pasternack L., Rossi P. (2014), “Kant's Philosophy of Religion”, [in:] The Stanford Encyclopedia of Philosophy (Fall 2014 Edition), E.N. Zalta (ed.), URL = https://plato.stanford.edu/archives/fall2014/entries/kant-religion/" [accessed 2.12.2017].
  17. Pera M. (2012), “Kant on Politics, Religion and Secularism,” [in:] Universal Rights ina World of Diversity. The Case of Religious Freedom, Pontifical Academy of Social Sciences, Acta 17: 546–577.
  18. Stevenson L. (2003), “Opinion, Belief or Faith, and Knowledge,” Kantian Review 7 (1): 72–101. Reprinted in Stevenson (2011).
  19. Stevenson L. (2011), Inspirations from Kant, Oxford University Press, Oxford.
  20. Tomaszewska A. (2016), “Kant’s Reconception of Religion and Contemporary Secularism,” Roczniki Filozoficzne (English Version) 64 (4): 125–148.