An Interpretation of the Deep Disagreement between Plato and Protagoras from the Perspective of Contemporary Meta-Ethics and Political Epistemology

Abstract

Since the early 20th century, two new disciplines emerged in the tradition of analytic philosophy: meta-ethics and political epistemology. Nevertheless, debates on such questions go back to the ancient Greeks and, in particular, to the debates between Plato and Protagoras. This article elucidates the controversy between Plato and the influential sophist Protagoras from the perspective of contemporary meta-ethics and political epistemology. It argues that the main motivation of Plato’s philosophical endeavors is to overcome Protagoras’s skeptical claims that no moral facts and no moral knowledge applicable to political issues exist. The paper defends the thesis that there exists a deep disagreement between Protagoras and Plato on the existence of moral facts and moral knowledge. A deep disagreement is a disagreement that cannot be resolved through the use of reasons and arguments. Applying the foundationalist approach Robert J. Fogelin proposes in his seminal paper “The Logic of Deep Disagreements”, this article argues that the deep disagreement between Protagoras and Plato exists because their political thought is based on “underlying principles” that clash. While Plato’s political philosophy rests on his religious and theological convictions, the political thought of Protagoras is based on his skepticism, relativism, and agnosticism.

1. Meta-Ethics and Political Epistemology

In a famous statement, Alfred Whitehead [1] (p. 39) claimed in 1929: “The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato.” Although Whitehead’s statement is exaggerated, Plato’s influence on Western philosophy is enormous and can even be traced in philosophical debates in the analytic tradition. The analytic approach to philosophy strives towards scientific, logical, and argumentative rigor. This article offers an interpretation of Plato’s political philosophy from the perspective of contemporary meta-ethics and political epistemology. Both disciplines are relatively young and belong to the analytic tradition.

The linguistic turn in the philosophy of the 20th century boosted the new branch of moral philosophy called meta-ethics. This new discipline does not defend any normative principles or ethical theories but investigates the nature of morality and the meaning of moral statements and judgments. As a philosophy of language, meta-ethics asks semantic questions: What do we exactly mean when we say that something is right, good, or just? In connection with its analysis of moral language and arguments, meta-ethics also asks ontological (or metaphysical) and epistemological questions: Do statements about what is right, good, or just refer to moral facts, or do they just express our personal—or our society’s—feelings, thoughts, and attitudes? Is there such a thing as moral knowledge or truth? In the language of contemporary meta-ethics, Plato defends1 a version of “moral realism” or “ethical realism”2. This is the position that claims that moral facts or an objective moral reality exist in mind-independent ways and that moral statements and judgments refer to such facts and to such a moral reality [3] (pp. 1–8), [4] (pp. 93–123)3. In contrast, anti-realists (moral skeptics, ethical relativists, or ethical subjectivists) deny that such facts and an objective moral reality exist.

According to contemporary philosophical language, Plato was not only an ethical realist but also a “cognitivist”. In meta-ethics, “cognitivism” is the position that moral judgments express beliefs that can be true or false and that there is such a thing as moral knowledge. “Non-cognitivists” reject the idea that moral knowledge is possible and claim “that moral judgements express non-cognitive states like emotions or desires” [3] (p. 3). It can hardly be disputed that Plato is both an ethical realist and a cognitivist who holds the good and the just to be objective moral facts that exist in mind-independent ways and about which moral knowledge can be achieved.

Political epistemology is a new discipline that applies the theory of knowledge to political issues [6,7]. Its questions focus on the area where the disciplines of epistemology and political philosophy intersect4. The fundamental question political epistemology asks is whether there is any knowledge that can ethically orientate political decisions. Political decisions are usually based on some kind of knowledge. When a government deals with another state, it attempts to collect, e.g., knowledge about its interests, its power to enforce them, and the people who govern. When legislators draft a new law, they seek to acquire knowledge about all areas affected and the social and political consequences. However, such kind of knowledge does not allow governments or legislators to answer the question of whether a policy is morally right or whether a law is just. The most fundamental question political epistemology asks is whether knowledge exists about values, the good, and about what is just and morally right.

Although political epistemology is a new discipline, debates on such questions go back to the ancient Greeks and, in particular, to the debates between Protagoras, Socrates, and his student Plato. This article elucidates the controversy between Plato and the influential sophist Protagoras from the perspective of contemporary meta-ethics and political epistemology. While Plato is both an ethical realist and a cognitivist, Protagoras is an anti-realist who denies the possibility of moral knowledge. Section 2 offers an interpretation of Protagoras’s thought. Section 3 argues that the main motivation of Plato’s philosophical endeavors is to overcome Protagoras’s skeptical claims that no moral facts and no moral knowledge applicable to political issues exist. In Section 4, the paper defends the thesis that there is a deep disagreement between Protagoras and Plato on the existence of moral facts and moral knowledge. A deep disagreement is a disagreement that cannot be resolved through the use of reasons and arguments. Applying the foundationalist approach Robert J. Fogelin proposes in his seminal paper “The Logic of Deep Disagreements” [8], this article argues that the deep disagreement between Protagoras and Plato exists because their political thought is based on “underlying principles” that clash. While Plato’s political philosophy rests on his religious and theological convictions, the political thought of Protagoras is based on his skepticism, relativism, and agnosticism.

2. Protagoras’s Political Thought

It is difficult to understand why several serious scholars claim that Socrates and not Protagoras of Abdera was the founder of political philosophy [9] (pp. 243–244), [10] (pp. 4–5). This view is partly based on the authority of the Roman orator, lawyer, and philosopher Cicero who famously claimed that “Socrates was the first to call philosophy down from the heavens […] and compel it to ask questions about life, customs, and things good and evil’ (Tusculanum Disputations V 4, 10, my trans.). The prevailing view according to which political philosophy begins with Socrates is highly problematic. Plato’s teacher, Socrates, was twenty years younger than Protagoras, who moved to Athens from Abdera, a polis in the north of Greece. Most importantly, the “human turn” of philosophical thought away from cosmological and metaphysical questions towards epistemological, ethical, and political issues happened as early as Protagoras. This is clearly attested by Plato’s dialogues Theaetetus and Protagoras, which are our main and quite reliable sources for Protagoras’s thought; cf. [11] (pp. 257, 268–269). Therefore, not Socrates but Protagoras should be interpreted as the founder of ancient Greek political philosophy. The sophist and philosopher lived as a resident alien in Athens and was a friend of Pericles, the leading democratic politician of the polis at the time.

Informed about the variation in customs and moral codes from one culture to another by the historian Herodotus, Protagoras defended the view that in moral and legal matters, no universal truths exist. According to Protagoras’s argument, if moral truths and an objective or universally valid morality existed, we could expect considerable agreement on moral beliefs. However, we can observe a lot of diversity in moral views and substantial disagreement on what is right and wrong. Therefore, no moral truths and no objective or universally valid morality exist. In the contemporary debate, this argument against the existence of moral truths and an objective or universally valid morality is called the argument from moral disagreement or the argument from relativity; cf. [5] (pp. xii–xiii) and [12] (pp. 3–4, 15–18) and [13] (pp. 1–3) and as well [14] (p. 37).

Despite Protagoras’s rejection of any universal truths in moral and legal matters, he argues that some moral beliefs or views about the good and just are more beneficial or useful than others (Plato, Theaetetus 166d–167d, 172a–b, 177d–e). Public debates and deliberations about what is good, just, and beneficial for the political community are characteristic features of democracy. In the myth the sophist presents in Plato’s dialogue Protagoras, he has Zeus distribute “justice” (dikê) and “respect” (aidos) to all citizens. As all citizens have a sense of justice and display respect for others, they all are political beings. Because they all possess such political virtues, the Athenians allow them all to participate in the political life of the polis. For Protagoras, politics is not a matter of knowledgeable experts but of all citizens (Plato, Protagoras 322c–323a). This is an important reason why Protagoras has been interpreted as a defender of (Athenian) democracy [9] (pp. 221–222), [15] (pp. 107–114), [16] (pp. 10, 25)5.

In the principal clause of his philosophy, Protagoras claims that “man is the measure (metron) of all things (chrêmata): of the things which are, that they are, and of the things which are not, that they are not” (Tht. 152a, trans. Levett, rev. Burnyeat). Because of this clause, Protagoras is usually “considered the first official voice of relativism” [17] (p. 27)6. According to Plato’s interpretation of the clause, all truths are relative to perceiving individuals (Tht. 152a). There is not one truth, but as many truths as there are perceiving individuals. Individual human beings are the measure of what is true. Applied to the field of morality, law, and politics, Protagoras’s epistemological relativism means that no such thing as “the just and unjust” has “by nature (physei) any being (ousia) of its own” (Tht. 172b, trans. Levett, rev. Burnyeat). In this statement from Plato’s Theaetetus, Protagoras denies the existence of mind-independent moral facts and an objective moral reality. In the language of contemporary meta-ethics, he was an “anti-realist”. Protagoras holds that “whatever any community (polis) decides to be just and unjust, and establishes as such, actually is what is just and right for that community and for as long as it remains so established” (Tht. 177d, trans. Levett, rev. Burnyeat). According to Protagoras’s ethical and legal relativism, everything that is just and legal is valid only for one polis and relative to its particular morality and laws. Just as there is no objective and universally valid truth, there is no objective or universally valid law and conception of justice. Rather, what is just and legal depends on the decisions of a particular political community. This is why Protagoras has been interpreted as a “political conventionalist” and “legal positivist” [15] (p. 112).

For Protagoras, legislation always aims at what the whole community holds to be its good and its advantage, “A community always makes such laws as are most useful to it” (Tht. 177d, trans. Levett, rev. Burnyeat). As already mentioned, this implies public debates and deliberations about questions of justice and about what is good and beneficial for the political community7. Protagoras view that some moral beliefs or views about the good and just are more beneficial or useful than others implies that he rejects an “absolute relativism” that claims “de gustibus non disputandum”8. For him, the sophist is able to persuade the citizens of a polis to establish the most useful or beneficial laws and conceptions of justice. Protagoras has been interpreted as an “ethical pragmatist” and “ethical consequentialist” who holds that the better moral beliefs and laws are those that work better and “have better practical results or consequences” [15] (p. 112)9.

3. Protagoras as Plato’s Main Opponent

The main motivation of Socrates’s and Plato’s philosophical endeavors is to overcome Protagoras’s skeptical claims that no moral facts and no moral knowledge applicable to political issues exist. For good reasons, Protagoras has been understood as “Plato’s Subtlest Enemy” [18]10. For Socrates and Plato, Protagoras’s view has a major shortcoming: because of the lack of objective and universal standards, he cannot provide sufficient ethical orientation for political decisions and can only partially overcome moral and legal disagreements, which are disagreements about which actions and laws are right or wrong. Despite the scholarly dispute on the question of how to distinguish the historical from the Platonic Socrates, it is rather certain that the historical Socrates, often regarded as the founder of “scientific ethics”, defended a view that is usually called “ethical intellectualism”11. Essentially, this view claims that virtue is knowledge. This means that a person who has true knowledge of the good will be able to implement this knowledge in her or his actions without getting sidetracked by appetites, passions, inclinations, and the strivings to obtain pleasure and avoid pain. In contrast to Protagoras, Socrates claims that philosophically accessible moral knowledge exists, which is able to ethically orientate personal and political decisions12. This claim is equal to an affirmative answer to the most fundamental question of political epistemology.

In his dialogues, Plato continues Socrates’s research on the relation of moral knowledge to ethical or political decisions. Plato also strives for clarification or definition of the terms and for knowledge of the essence of things. According to the testimony of Aristotle, as a young man Plato accepted Heraclitus’ teaching, according to which there can be no knowledge of sensually perceptible things because they are constantly changing. Therefore, Plato’s striving for knowledge of the essence cannot refer to sensually perceptible things. Rather, it must be directed to another object area that is not subject to constant change (Met. 1.5–6, 987a32–987b9). According to Aristotle, the Pythagorean metaphysics of numbers, which Plato probably got to know during his first trip to Italy, offered a model for such an object area (Met. 1.6, 987b8ff.). The Pythagoreans considered the sensually perceptible things as images of numbers, which they understood as the essence of the world. Probably with it a separation of the world into a sensually perceptible world of becoming and passing away and an imperishable world of the true being went along. Parmenides, at the latest, explicitly makes this distinction. In the first part of his didactic poem, he presents the truth about being, and in the second part the opinions of mortals about the sensually perceptible cosmos. With his epistemological distinction between “opinion” (doxa) and “knowledge” or “cognition” (epistêmê) from the middle dialogues, Plato ties in with this two-world doctrine. He assigns unreliable opinions to the sensually perceptible world of becoming and passing away, of which there can be no knowledge. In contrast to Parmenides, however, Plato does not completely deny the being of the latter world but declares that it oscillates between being and non-being (Resp. 5.478b–e). Cognition and knowledge, however, can only be achieved of the world of true being, which consists of spiritual and unchanging numbers, geometric figures, and forms (eidê) (Resp. 5.477a–480a; Plato’s Timaeus 27e–28a, 48e–49a, 52a; cf. [23] pp. 355–358).

In Plato’s search for knowledge that can ethically orientate people’s lives and political decisions, mathematics plays a central role. This is elucidated by the educational program he outlines for the future philosophers and rulers in the Republic. The 10-year study of arithmetic and geometry constitutes the preliminary stage for dialectics, the method to achieve complete knowledge of the world of true being. For the study of mathematics causes the human power of cognition to turn away from the realm of sensually perceptible things of the world of becoming and to turn upward toward the realm of true and unchanging being (Resp. 7.521c–d, 7.525a–e, 7.527a–c). For instance, the sensually perceptible circle that a math teacher draws on the blackboard is not the true circle. The true circle, defined as the amount of all points in a plane that have the same distance from a center, exists only in the realm of thought. The many different drawn circles are only images of the one true and eternally constant circle. This one circle, which exists only as an object of thought and knowledge, can be understood as the “form” of the circle (strictly speaking, however, Plato distinguishes—Resp. 6.510c–511d—between numbers and geometrical figures, on the one hand, and forms, on the other; cf. the debate on mathematical objects [23] (pp. 400–401). It would be quite possible that the insight into the “supersensible” nature of mathematical objects was the very beginning of Plato’s theory of forms13. However, his daring theoretical generalization that the true essence of all ethical, aesthetic, etc. phenomena and of most sensually perceptible objects must be understood as a “form” is far less plausible (cf. the discussion of the controversial question of which things there are forms at all [23] (p. 397).

Plato’s epistemological distinction between “opinion” (doxa) and “knowledge” or “cognition” (epistêmê) corresponds to his two-world doctrine. Both are presumed in his famous analogy of the divided line. The major division of the analogy is between the world of changeable and sensually perceptible things, about which only opinions exist, and the world of immutable true beings, about which knowledge is attainable. Of course, Plato’s main interest concerns the latter world, the area of the intelligible. He further distinguishes the objects situated in this world in an area of numbers and figures, on the one hand, and an area of forms, on the other. He assigns two kinds of cognition to these two areas. While “thought” (dianoia) can grasp the “mathematical objects” (mathêmatika), “intellection” (noêsis) is able to discern the “forms” (eidê). The knowledge achieved through “intellection” is clearer and more distinct than the mathematical knowledge of “thought”. It is also purer than mathematical knowledge because it does not have to rely on the images of sense perception, such as a drawn circle. The central difference between the two types of cognition is that mathematical understanding starts from hypotheses and presuppositions—such as principles and definitions—that it cannot capture or trace back to an ultimate principle (cf. [25] pp. 107–109). In contrast, the pure knowledge of intellection, which uses the dialectical method to attain knowledge, can ascend to the highest and last principle, the form of the good, through the interrelation between the forms (Resp. 6.511b–c, 7.532a–b).

It is astounding that in the Republic Plato does not elucidate the dialectical method of the philosophers that allows them to ascend to the world of the forms. In this dialogue, he relates dialectics primarily to the highest form, the form of the good, which he regards as the “cause of the knowledge and truth” (Resp. 6.508e, trans. A. Bloom). The dialectical path of intellection consists of a spiritual ascent to this “goal of all knowable things”. A philosopher treads this path when he “tries by discussion–by means of argument without the use of any of the senses–to attain to each thing itself that is and doesn’t give up before he grasps by intellection itself that which is good itself”, which Plato considers “the very end of the intelligible realm” (Resp. 7.532a, trans. A. Bloom; cf. Plato’s Phaedo 65a–68b). Dialectical thinking is a pure thinking that does not need sense perception and experience but rather turns away from them. It aims at knowledge of the essence of things and, thus, of the word of forms (Resp. 7.534b). Ultimately, it aims at cognition or vision of the highest form, the form of the good. In later dialogues, such as Sophistes and Politikos, Plato gives more precise explanations of the dialectic procedure and its subtypes.

Plato’s search for knowledge that can ethically orientate people’s lives and political decisions aims at the world of true being, the word of forms. Plato is mainly interested in ethical and aesthetic forms such as the form of the good, just, and beautiful. The good in itself and the other forms constitute an “intelligible region” (noêtos topos) that exists separate and independent from the human mind and the world human beings perceive with their senses (Resp. 6.509d). The “intelligence” (nous) of the philosopher is not only able to behold the good in itself and the other forms but is kindred to them (Resp. 6.490b, 10.611e). A long theoretical education and the dialectical method allow the logistikon of the philosopher and its “intelligence” (nous) to attain knowledge of this intelligible region that constitutes an objective moral reality. For instance, in the Republic Plato understands justice as a mind-independent moral fact. He defines justice in the polis as “the minding of one’s own business and not being a busybody” and claims that justice in the human being is achieved when every “part” of the soul “minds its own business” (Resp. 4.433a–b, 4.443a–b, trans. A. Bloom). Such definitions of justice are not satisfactory [26] (pp. 24–28). However, they elucidate the previous statement that Plato was an “ethical realist” and “cognitivist” who holds the just and the good to be an objective moral reality about which moral knowledge can be achieved. According to Plato’s theory of forms, everything good, just, and beautiful possesses these qualities because it participates in the forms of the good, just, and beautiful. Knowledge about these forms is capable of ethically orientating political decisions. Plato’s ethical realism and cognitivism has also a religious and theological dimension. According to him, the true political philosopher discerns a “divine paradigm” (theion paradeigma) of the just and good political order in the intelligible region that should be imitated as much as possible (Resp. 5.472b–473b, 6.500c–501b, 7.517c). According to Plato’s famous statement, this divine paradigm cannot be politically realized unless “the philosophers rule as kings or those now called kings and chiefs genuinely and adequately philosophize, and political power and philosophy coincide in the same place” (Resp. 5.473c-d, trans. Bloom).

4. The Deep Disagreement between Protagoras and Plato and Its Basis

Protagoras and Plato vigorously disagree on the basic problem of political epistemology whether there is any knowledge that can ethically orientate political decisions. A better comprehension of this disagreement is not only significant for a better understanding of the discipline but also of reason in general. In contemporary philosophical language, the disagreement between Plato and Protagoras is a dispute between an ethical realist and an anti-realist who were undoubtedly epistemic peers. It is further a dispute between a philosopher who believes in the possibility of moral knowledge (about the good and justice), and one who does not. Such disagreements are at the center of contemporary meta-ethical arguments. As the ongoing debate suggests, the discussants are far from overcoming their dissent and from reaching a consensus. This prompts the conclusion that such disagreements are deep disagreements. Deep disagreements are disagreements in good faith that cannot be resolved through the use of reasons and arguments [8] (pp. 8, 11)14. According to Fogelin, deep disagreements are resistant to rational solutions because of a clash of “underlying principles” or “framework propositions” [8] (pp. 8–9)15. Fogelin’s foundationalist approach allows for an explanation of the deep disagreement between Protagoras and the two Athenians on the existence of moral facts and moral knowledge. The reason for their deep disagreement is that their respective epistemological and political thought is indeed based on “underlying principles” that clash.

While Plato’s political philosophy rests on his religious and theological convictions, the political thought of Protagoras is based on his skepticism, relativism, and agnosticism. As previously mentioned, Plato claims that the true political philosopher is able to discern a “divine paradigm” (theion paradeigma) of the just and good political order in the world of true beings, the word of forms. Plato often states that the forms are divine. In a famous passage, he characterizes the form of the good in a way that clearly suggests that he holds it to be the supreme deity: “the good isn’t being but is still beyond being, exceeding it in dignity and power” (Resp. 6.509b, trans. Bloom)16. In the Laws, Plato does not unequivocally refer to his theory of forms. Nevertheless, he makes the “underlying principle” of his political thought explicit. Countering Protagoras’s claim that man is the measure of all things, he emphasizes: “In our view it is God who is preeminently the ‘measure of all things’, much more so than any ‘man’, as they say” (Laws 4.716c; trans. T. Saunders; cf. [2] pp. 238, 255).

Protagoras’s political thought rests on his skepticism, relativism, and agnosticism. His clause that man is the measure of all things was the opening passage of his work Alêtheia (Truth). Similarly, the principal clause of Protagoras’s philosophy of religion was placed at the beginning of his treatise On the Gods:

“Concerning the gods I cannot know whether they exist or not [nor what form (idea) they might have], for many are the obstacles that prevent our knowledge: the obscurity of the subject and the brevity of human life” (Diels/Kranz 80B4, my trans.).

Human beings are neither able to verify whether the gods exist through their senses nor through their reason. The impossibility of achieving objective knowledge and truth about the gods can also be derived from Protagoras’s claim that man is the measure of all things. From Protagoras’s skepticism and relativism it follows that his political thought does not acknowledge any objective or universally valid conception of justice and the good. From his agnosticism, it ensues that he does not recognize any form of divinity that might be able to orientate political decisions. Neither the human mind in general nor particular moral, legal, and political decisions and actions can rely on any divine or higher standard. Since human beings have no access to any higher authority, they depend exclusively on human judgments and standards such as human benefit, utility, and practical consequences (cf. [15] pp. 107–109). From the perspective of Protagoras’s skepticism, relativism, and agnosticism, it seems plausible to reject the existence of any objective moral reality or mind-independent moral facts and moral knowledge. Even if such phenomena existed, human beings have no means of accessing and knowing them.

5. Conclusions

To be sure, agnosticism does not conclusively rule out the possibility that an objective moral reality or mind-independent moral facts exist. Skepticism and relativism have many different forms and are still controversial and much-discussed views today17. Nevertheless, as “underlying principles” of a meta-ethical position they clearly suggest an anti-realist view. If no recourse to a divine reality or a higher standard is possible, the existence of an objective moral reality or of mind-independent moral facts seems unlikely. Of course, there are many other arguments that render the existence of such facts and ultimate moral knowledge unlikely18.

If there are no moral facts and no objective moral reality, there is no moral knowledge that could ethically orientate political decisions; nothing exists on which such knowledge could be based, or to which it could refer. By contrast, Plato’s philosophical theology can explain the existence of an objective moral reality. If the cosmos exists as a divine order that contains “reason” (nous), and if human “intelligence” (nous) is kindred to this order and able to perceive it, true philosophers are capable of achieving moral knowledge about the mind-independent forms of the good and just. However, Plato has serious difficulties in rationally defending both his philosophical theology and his theory of forms, which are the “underlying principles” of his ethical realism and cognitivism. Considering all the criticism of religion and theology of the 18th and 19th centuries, in the world of today, the Platonic version of ethical realism and cognitivism is hard to defend. Of course, not all contemporary versions of ethical realism and cognitivism are pure footnotes to Plato’s ontological (or metaphysical) and epistemological thought. These positions can also be defended without recourse to a philosophical theology or Plato’s theory of forms. However, ethical realism and cognitivism seem to have an affinity to religious and theological thought and its corresponding idea that there exists some form of a given and good order or a natural law in the world and the cosmos that can orientate human beings in their private and political actions.

This article has defended the thesis that there is a disagreement between Protagoras and Plato on the existence of moral facts and moral knowledge and that this disagreement is deep because it cannot be resolved through the use of reasons and arguments. The paper applied Fogelin’s foundationalist approach to disagreements and argued that the deep disagreement between Protagoras and Plato exists because their political thought is based on “underlying principles” that clash. As shown, Plato’s political philosophy is based on his religious and theological convictions, while Protagoras’ political thought rests on his skepticism, relativism, and agnosticism. This result is important because it generates awareness of how different parts and aspects of a philosopher’s thought are related to each other and of how strongly their views on one issue can depend on their views on another issue. In the case of Protagoras and Plato, their views on ethics and meta-ethics are considerably swayed by their views on religion or theology. The result of this article is also important because it generates awareness that there are often more profound reasons behind disagreements among philosophers. To truly understand moral and political disagreements, one often needs to understand the underlying and more fundamental disagreements on which they are based. Whether these kinds of disagreements, which are disagreements on “underlying principles” that clash, can be resolved through the use of reasons and arguments remains an open question19. Be that as it may, it seems promising to apply Fogelin’s foundationalist approach to analyze a variety of other moral, political, and philosophical disagreements and to search for underlying deeper disagreements.