Cornelius Van Til and Rousas John Rushdoony, Part 1: Every Thought Captive
This article is an introduction to the ideas of Rousas John Rushdoony's theological mentor, Dr. Cornelius Van Til, who taught at Westminster Theological Seminary in Philadelphia for five decades. While many readers of Faith for All of Life are already intimately familiar with Van Til's ideas, I hope this article is a useful refresher of how Van Til's basic ideas-especially his presuppositional apologetics-directly relate to the ministry of R. J. Rushdoony and the work of the Chalcedon Foundation.
For those new to either Rushdoony or Van Til, I hope this article might also serve as an introduction to "presuppositional apologetics," the basic system behind Rushdoony's concept of Christian Reconstruction. With that said, it is important to note that this essay isn't about Rushdoony. Instead, it is the foundation for an article that will appear in a future issue of Faith for All of Life that will specifically document the personal friendship and professional collaboration between Rushdoony and Van Til. This current article focuses on the early life and intellectual career of Van Til. It shows how Van Til's theology grew out of a tumultuous period in the history of Reformed Christianity in the United States. Further, it discusses how Van Til's insights led Rushdoony to conclude that Christian education is the precondition for American cultural renewal.
Strangers on a Train
Readers of my earlier articles on R. J. Rushdoony's missionary years in Nevada will recall that he first encountered Cornelius Van Til in March 1946 while traveling back to Owyhee, Nevada, after an extended trip to the East Coast.1 During his East Coast visit, Rushdoony heard a "well-known neo-orthodox theologian" "savagely" attack Van Til's ideas.2 When Rushdoony stopped in a small Colorado town to visit another minister, he stumbled across a copy of Van Til's The New Modernism3 in the minister's library. Noting Rushdoony's interest, the minister responded, "You want it? Take it."4 Rushdoony took the book and began reading it on his return trip to Nevada. In a train full of troops returning home from the Second World War, Rushdoony hardly noticed the commotion around him as he consumed the book. "When I reached Denver," Rushdoony told an interviewer decades later, "I had to wait several hours in the railroad station. I just sat there and didn't take the time to go and eat. I was there five or six hours."5
In Denver, the rapt Rushdoony read a dense, carefully argued rejection of the theologies of Karl Barth and Emil Brunner. The book would have been notable to Rushdoony because it was one of the earliest sustained critical works written by an American on the theologians Barth and Brunner for a Reformed audience.6 But if the subject matter lured Rushdoony in, the book's style and theological project hooked him. Today The New Modernism is perhaps best known as the first book-length exposition of Van Til's presuppositional apologetics. For this reason, instead of focusing on the text's specific argument against Barth and Brunner, it is more useful to provide a general overview of Van Til's presuppositional method that undergirded the book.
Van Til argued that the relationship between God and His creation provided an important foundation for reassessing the nature of human knowledge. In a nutshell, if God created the universe, then He also created the means for interpreting it. To try to think independently of God is not only impossible, it is the ultimate human temptation that leads to sin in its very essence. Before offering a full exposition of these insights, it is worth pausing a moment to consider Van Til's life and how it related to his theological development. To begin with, Van Til's unique status as a political and religious refugee had a profound influence on his theological ideas and, in turn, on Rushdoony's idea of Christian Reconstruction.
The Education of Cornelius Van Til
Born in Grootegast, the Netherlands, in 1895, Van Til and his family moved to the United States and settled in northern Indiana in 1905. The Van Tils raised their son within the cultural context of the Dutch Afscheiding, the "Secession" or "Separation" movement, a nineteenth-century effort to insulate the Dutch Reformed Church from state intervention. State-sanctioned persecution drove many of the largely rural, poor secessionists to seek refuge in the New World. In Indiana, the Van Tils joined a separatist community of conservative Dutch immigrants who jealously protected their linguistic and religious heritage. Growing up in this tight-knit community of religious dissenters, Van Til hardly drew a distinction between his Old World cultural heritage and the standards of the Christian Reformed Church in North America, a conservative communion that created sharp boundaries between its polity and modern American society.
Van Til followed a traditional path within the Christian Reformed Church toward a ministerial position, first attending Calvin College in Grand Rapids, Michigan, and then pursuing a divinity degree at Princeton Theological Seminary (PTS) in New Jersey. After seminary, he went on to earn a Ph.D. in philosophy at Princeton University, and after a short period as a preacher he eventually moved away from preaching toward teaching.
His philosophy degree brought his theological training into dialogue with the problems raised by modern philosophers in the United States. Specifically, Van Til became interested in epistemology. Epistemology is a field of philosophy that studies how humans know what they know; that is, epistemology is the study of human knowledge.
Since the work of the German philosopher Immanuel Kant (1724-1804), many European and American philosophers focused their attention on the problem of knowledge. Kant-and I'm simplifying greatly here-focused his attention on how human beings create knowledge and come to know the world in which they live. Building on Kant's work, philosophers began to focus more tightly on problems of human knowledge and language. Some concluded that humans had the ability to reason independently of divine authority, and these philosophers began to move away from metaphysical and theological questions related to the being and nature of God. Kant and his successors have asked questions such as, "How do human beings create knowledge about the world?" "What is the foundation of human reason?" Van Til found these sorts of questions blasphemous because they implicitly-or explicitly-reject God's ability to determine meaning and construct human knowledge. Consequently, at PTS Van Til developed a Christian alternative to post-Kantian philosophy that foregrounded God's sovereignty over human knowledge.
With this background in mind, we can now turn to Van Til's development of presuppositional apologetics. The next section outlines Van Til's revolutionary ideas about the relationship between Jesus Christ and human knowledge. Further, it demonstrates how his ideas were directly related to the creation of a new seminary that would eventually produce two of the most important voices in Rushdoony's Christian Reconstruction movement, Gary North and Greg Bahnsen.
Westminster Theological Seminary and the Birth of Presuppositional Apologetics
While a graduate student in the 1920s, Van Til witnessed the struggles between theological conservatives and theological liberals at PTS. Theological liberals, or modernists as they are also known, tended to be open to modern philosophy and other intellectual trends such as Darwinism and higher criticism. Proponents of Darwinism suggested that aspects of the Bible, such as the creation account in Genesis, conflicted with modern scientific findings and could not be taken literally. Furthermore, those supporting higher criticism believed that literary analysis of the Bible suggested many of the books had factual errors and contradictions that betrayed the hand of human artifice rather than affirming divine authorship.
When PTS began hiring faculty who subscribed to both Darwinism and higher criticism, Van Til followed a group of secessionist faculty, led by J. Gresham Machen, to form a new seminary called Westminster Theological Seminary. Westminster's very name indicated that the secessionists were appealing to the traditional authority of the Reformed churches' Westminster Confession of Faith, first adopted by Reformed Christians in 1646. Van Til and the other founding faculty hoped that the new Westminster Theological Seminary would serve as the conservative alternative to what they perceived as the liberal trends at Princeton.
At Westminster, Van Til developed a presuppositional apologetic method that operated in sharp contrast to the then-dominant Reformed tradition of evidentialist apologetics. Evidentialist apologetics is rooted in the Scottish Common Sense philosophical tradition as it was adopted and adapted by American intellectuals and theologians in the eighteenth and nineteenth centuries. According to the historian Mark A. Noll, American evangelicals generally highlighted three key aspects of Common Sense philosophy. First, Noll points out that American evangelicals traditionally emphasized an epistemology that asserts, "[O]ur perceptions reveal the world pretty much as it is."7 Second, the tradition emphasized that human beings can infer ethical standards from their innate nature, thus suggesting that certain standards of moral behavior are shared by all humans.8 Finally, evidentialists advanced their project through a vaguely Newtonian scientific methodology that "encouraged evangelicals to believe that the end product of theology was a system of certain truths, grounded on careful induction from simple facts, eschewing hypothetical flights of fancy, and providing a universal and unvarying picture of God and his ways."9
Although evidentialist apologetics dominated Princeton Theological Seminary in the late nineteenth and early twentieth century, Van Til rejected this traditionally accepted method. Instead, he insisted that such an empiricist method presumes the autonomy of human beings to think independently from God and Scripture. Building on this point, he insisted that human beings could not think a single thought independently of God. This led Van Til to conclude that intellectual autonomy, self-rule of the mind, is a sin because it rejects God's authority, whereas theonomy, God's rule of the mind, is the only source for legitimate knowledge. Those who defend orthodox Christianity must begin with the ultimate reality of Jesus Christ and the Trinity as the source of all knowledge. Any other point of apologetic departure is not only illogical, but is also a rejection of God's sovereignty over all of creation.
Van Til argued that the Trinity is the only proper starting point for understanding reality. He believed that Christianity, rightly understood, posited a two-layer theory of reality.10 He drew a hard and fast distinction between God and His creation. The being and nature of the first layer, God, is "infinite, eternal, and unchangeable."11 The second layer is the created universe, which is finite, temporal, and constantly changing.12 Between Creator and created, there is an insurmountable gulf that cannot be bridged by any willful means of a created being. Instead, the only bond between God and His creation comes from grace. The recognition of this chasm between God and creation is, in Van Til's mind, the essential presupposition upon which orthodox Christianity is founded. Christians must presuppose this separation in order to correctly comprehend the nature of God and creation. Any attempt to collapse God into creation or to subsume creation into the nature of God is a false, non-Christian presupposition.
The Problem of Sin in Van Til's Thought
Van Til's epistemology begins with the presupposition that God is completely self-contained, has exhaustive knowledge of His self, and consequently also has exhaustive knowledge of His creation. In terms of creation, since "all aspects" of the universe are "equally created," then "no one aspect of reality may be regarded as more ultimate than another. Thus the created one and many may in this respect be said to be equal to one another; they are equally derived and equally dependent upon God who sustains them both."13 Humanity can never have exhaustive knowledge of this creation by attempting to reduce one aspect of nature to another or by trying to subsume the particulars of nature into an abstract totality. Instead, as John M. Frame, a theologian and former student of Van Til, summarizes,
Insofar as we can know the world, it is because [God] gives us revelation and the ability to repeat his thoughts on an analogical, finite level. And insofar as we cannot know the world, we can trust that the world is nevertheless an intelligible whole. Things that are mysterious to us do not spring from an ultimate chaos or meaninglessness; they spring, rather, from the wonderful riches of God's thought, which transcends our understanding.14
The plurality and unity of creation are perfectly represented in the plurality and unity of the Trinity. Just as God can no more be reduced to a single person of the Trinity, no aspect of nature can be reduced to another. Similarly, just as the persons of the Trinity only have meaning in relation to one another, so too do all aspects of nature.
Human beings sin when they attempt to apprehend reality independently of God's revelation without acknowledging our finite, subordinate relationship to God. As Van Til explains, God gave Adam and Eve, humanity's "first parents," a prescriptive path "marked by love and obedience" if they "led their lives in the direction he indicated to them."15 Rather than follow this path, they instead listened to Satan who told them "how free he had become since declaring his independence of God." "To be self-determining," Satan explained, "man must surely be able to decide the ‘nature of the good'-regardless of what God says about it." Adam, after listening carefully to Satan's appeal and weighing it against God's plan, concluded,
You are right Satan, I must first decide whether such a God as often speaks to us (1) knows what the "good" for us is, (2) controls history so that he can determine what will happen if we disobey him, and (3) has the right to demand obedience from us. After I decide these issues, and if the answer is "yes," then I shall obey him. Certainly not before.16
Christians agree on what happened next: Adam and Eve sinned precisely because they succumbed to Satan's temptation to "be as gods, knowing good from evil."17 At that precise moment, human beings asserted the primacy of their intellectual autonomy over God's sovereignty.
Humanity's fall into sin was precipitated by a desire to reason independently from God's authority. Accordingly, humanity's pretense to independent knowledge becomes a matter of rebellion against God's plan because "[d]eep down in his mind every man knows that he is the creature of God and responsible to God. Every man, at bottom, knows that he is a covenant-breaker. But every man acts and talks as though this were not so."18 If thinking is an explicitly religious activity, then this epistemological claim has political implications: thinking becomes a matter of kingship, power, rebellion, and, in the final analysis, warfare. Either human thought recognizes God's sovereignty, or it does not.
For human beings, the foundation of thought must be God's Word. As Wesley A. Roberts notes in his summary of Van Til's epistemology, "Van Til insists that all knowledge that any finite creature would have must rest upon the revelation of God. Thus the knowledge that we have of the simplest objects of the physical universe is based upon the revelation of God."19 Scripture is the objective yardstick by which all human thought must be measured, and when found lacking, by which it must be disciplined. In Van Til's words, "[I]f man is not autonomous ... then man should subordinate his reason to the Scriptures and seek in the light of it to interpret his experience."20 Thus, for Van Til Scripture is both authoritative and authoritarian-it both authorizes human experience and constitutes it-whether we recognize it or not.21
To help his students understand the relationship between God, creation, and knowledge, Van Til illuminated his theology with a series of chalkboard doodles. The most famous of these sketches depicts his two-level, "theocentric" model of reality: two circles, one over top of the other.22 The superior circle is the larger of the two. It depicts God, while the smaller circle represents creation. The circles do not touch, leaving "no ontological bridge" between the two (see figure on left/above).23 Two flimsy lines overlap the perimeters of each loop forming a narrow, but perceptible bridge of grace between the Creator and His created. In contrast to this "theocentric" conception of the two-layer nature of reality, Van Til used a single circle to depict the "anthropocentric" conception of reality (see figure on right/above). Here, a lone circle indicates humanity's sinful attempt to apprehend reality as a singular structure, which is either reducible to its constitutive elements or irreducible to its abstract totality. Whether conceptualized as reducible or irreducible, this "anthropocentric" perspective denies the reality of a separate, self-contained God. Within Reformed circles, these heuristics have become iconic representations of Van Til's understanding of the relationship between God and humanity.
Antitheses: Abraham Kuyper and Van Til at Westminster
Van Til's complex ideas about human knowledge and their relationship to sin grew from the theological turmoil he witnessed at PTS. First, as we have seen and I elaborate below, his theological and apologetic perspectives were partly a product of his own education as the son of Dutch immigrants struggling to understand the proper relationship between their cultural heritage and their place in turn-of-the-century American society. Second, Van Til developed his apologetic method in the age of an ascendant theological modernism that was splitting the Presbyterian Church asunder. In the face of a series of setbacks for theological conservatives-including the Auburn Affirmation, the reorganization of Princeton Theological Seminary, and the fracturing of the Presbyterian Church in the United States-Van Til offered his apologetic method as a means of rejecting the general trend of the secularization and modernization of the church.
Beginning with his Dutch Reformed heritage, it is important to note that the teaching of the Dutch theologian and statesman Abraham Kuyper (1837-1920) heavily influenced Van Til.24 Kuyper is largely credited as the father of "neo-Calvinism," a movement whose adherents see Calvinism as a comprehensive, coherent Christian worldview capable of resisting and rolling back the social, cultural, and political advances of the Enlightenment and modernism.25 In order to combat the ideas of the Enlightenment, "Kuyper insisted on the absolute separation, or ‘antithesis,' between the Christian and the modern worldview that came to prominence in the French Revolution."26 He encouraged Calvinists to draw sharp distinctions "between Christian approaches to social issues and those supported by non-Christian or ‘apostate' thought."27
Kuyper labeled this concept of the separation between Christian and non-Christian thinking the "antithesis." Only Christians, Kuyper argued, could be self-conscious. In fact, non-Christians could not think in a consistently non-Christian manner, because such a project would ultimately lead to utter meaninglessness. Non-Christians, Kuyper concluded, therefore "borrow" all knowledge and meaning from a dull apprehension of their nature as a created beings.
Van Til wholeheartedly embraced Kuyper's concept of the "antithesis" and rigorously developed it to a degree that Kuyper did not. By coupling Kuyper's concept with his own reading of post-Kantian philosophy, Van Til developed his "pioneering insight" that the "given presuppositions of any philosophical position predetermined and governed much of its later outworking."28 Indeed, Van Til recognized that modern thought is "is largely preoccupied with the theory of knowledge," and therefore insisted that Christians needed to rigorously expound how their epistemology differed from non-Christian systems of thought.
Van Til's primary innovation was to expand Kuyper's ideas to assert that Christian and non-Christian epistemologies have little or nothing in common. By adopting and developing the "antithesis" of Dutch Reformed Calvinism, Van Til declared war on any system of thought that did not accept Scripture. Within the context of the early twentieth-century conservative/liberal theological controversies, Van Til's ideas made him one of the most revolutionary thinkers in the fundamentalist camp. His presuppositional method challenged fundamentalists to be more Biblical in their orientation and to draw sharper distinctions between themselves and theological modernists. Van Til's was not a stance of moderation or compromise.
Conclusion: Van Til and the Origin of Christian Reconstruction
Rushdoony's chance encounter with The New Modernism in a friend's library precipitated his rapid adoption of the presuppositional perspective. After reading Van Til in March 1946, Rushdoony immediately began adopting Van Tillian themes and terminology in his letters. In a letter to a Presbyterian Mission official, Rushdoony offered the first clear exposition of Van Til's ideas in his correspondence without mentioning Van Til: "I have been doing considerable studying since my coming here and am increasingly convinced that without a doubt our present day Biblical studies are grounded, not on sound scholarship but on philosophical presuppositions and are thus unrelated to fact."29 Instead, Rushdoony explained that the zealous faithful look at scholarship with skepticism because it seems to deaden their encounter with God. Van Til's ideas had clearly taken root in Rushdoony's mind. From the first appearance of the term "presupposition" in his correspondence, to a clear rejection of the anti-intellectualism and the dispensational bent of contemporary fundamentalists, Rushdoony had seen the critical power of Van Til's ideas.
By 1947 Rushdoony began encouraging his friends to read The New Modernism, and by the early 1950s Rushdoony embraced a systematic Reformed perspective based on Van Til's presuppositional apologetics. He became convinced that the only way Christians could renew American culture was through epistemological self-awareness. This insight was the origin of the concept of Christian Reconstruction and the work of the Chalcedon Foundation. From it he developed the notion that Christians can reconstruct the world by bringing "every thought captive"30 to the Word of God as embodied in the Bible. By developing this focus on epistemology, Rushdoony spent the 1950s authoring his first withering attacks on secular humanism and, most importantly, secular education.31 He worked tirelessly to popularize Van Til and sought to empower Christian educators and thinkers.
In a future issue of Faith for All of Life, I will take up where this story leaves off and provide readers the story of the long, productive friendship between Rushdoony and Van Til. Their collaboration emerged from their deep personal respect for each others' ideas and their shared desire to develop Christian self-awareness as the prerequisite for cultural renewal. We'll see how Rushdoony helped popularize and spread Van Til's ideas to a wide audience and learn how the two men spent their lives as champions of one another's work.
1. For a history of Rushdoony's time in Owyhee, see Michael J. McVicar, "‘First Owyhee, and then the World:' The Early Ministry of R. J. Rushdoony," Faith for All of Life (November/December, 2008): 18-22, 33.
2. R. J. Rushdoony to Cornelius Van Til, October 23, 1947, R. J. Rushdoony Library, Vallecito, CA (hereafter cited as RJR Library).
3. Cornelius Van Til, The New Modernism: An Appraisal of the Theology of Barth and Brunner (Philadelphia, PA: Presbyterian and Reformed Publishing Company, 1946).
4. Janet S. Larson, "The Oral History Interview of Dr. Rousas John Rushdoony," 1980, RJR Library, 33.
6. In assessing the influence of Van Til's criticism of Barth and Brunner, Phillip R. Thorne insists, "Without a doubt the history of Barth's reception by American Evangelicals must begin with Dr. Cornelius Van Til ... Not only was he one of the earliest, most prolific and well read of Fundamentalist Evangelical interpreters, Van Til was the most influential" (Phillip R. Thorne, Evangelicalism and Karl Barth: His Reception and Influence in North American Evangelical Theology [Pittsburgh, PA: Pickwick Publications, 1995], 33). Gregory G. Bolich reaches a similar conclusion regarding the importance of The New Modernism, arguing that Van Til and those who followed his analysis convinced many evangelicals that Barth's "neo-orthodoxy" was neo-heresy: "Under Van Til ... the work of Barth was declared off limits to a generation of evangelicals. Van Til's general conclusions, as well as many of his specific criticisms, became the primary response of the American conservative community to Karl Barth" (Gregory G. Bolich, Karl Barth & Evangelicalism [Downers Grove, IL: InterVarsity Press, 1980], 66-67). Bolich is careful, however, to point out that many conservatives rejected Van Til's analysis as a mere "caricature" of Barth's theology (ibid., 71; for Bolich's summary of these criticisms see pages 70-73). Van Til's biographer John R. Muether notes that Van Til helped set the tone for Barth's reception in the United States partly because he had the advantage of reading Barth in the original German years before many of the Swiss's key writings appeared in English (Cornelius Van Til: Reformed Apologist and Churchman, American Reformed Biographies [Phillipsburg, NJ: Presbyterian and Reformed, 2008], 121). Finally, George Marsden describes Van Til as "one of the few in the fundamentalist fold equipped philosophically and linguistically to deal with the complexities of European dialectic theologies." He concludes, "Few fundamentalists read [The New Modernism], but many repeated the title" (George M. Marsden, Reforming Fundamentalism: Fuller Seminary and the New Evangelicalism [Grand Rapids, MI: W. B. Eerdmans, 1987], 101).
7. Mark A. Noll, "Common Sense Traditions and American Evangelical Thought," American Quarterly 37, no. 2 (Summer 1985): 220.
8. Ibid., 221-222.
9. Ibid., 224.
10. Cornelius Van Til, The Defense of the Faith, Third Edition (Phillipsburg, NJ: Presbyterian and Reformed, 1967), 35; 23-30. See also Wesley A. Roberts, "Cornelius Van Til," in Reformed Theology in America: A History of its Modern Development, ed. David F. Wells (Grand Rapids, MI: William B. Eerdmans, 1985), 122.
11. Roberts, "Van Til," 119.
12. Ibid., 119.
13. Van Til, Defense of the Faith, 27. Rushdoony eventually translated this insight into a political vocabulary to assert that all aspects of social reality are equal to one another; therefore, no aspect of society can be reduced to another and, conversely, no aspect can claim superiority over another. See Rousas John Rushdoony, The One and the Many: Studies in the Philosophy of Order and Ultimacy (Fairfax, VA: Thoburn Press, 1978).
14. John M. Frame, Cornelius Van Til: An Analysis of His Thought (Phillipsburg, NJ: Presbyterian and Reformed, 1995), 76.
15. Cornelius Van Til, "My Credo," in Jerusalem and Athens: Critical Discussions on the Theology and Apologetics of Cornelius Van Til, ed. E. R. Geehan (Phillipsburg, NJ: Presbyterian and Reformed, 1971), 5. See also, Van Til, Defense of the Faith, 33-35; Cornelius Van Til, Apologetics, (Phillipsburg, NJ: Presbyterian and Reformed, 1976), 56-57.
16. Van Til, "My Credo," 5-6.
17. Genesis 3:5.
18. Van Til, Apologetics, 57.
19. Roberts, "Van Til," 124.
20. Quoted in ibid.
21. Roberts, "Van Til," 124; and Van Til, Defense of the Faith, 32-33.
22. As one former student noted, "Every student of Van Til can instantly recall the characteristic Van Tillian blackboard graffiti: the foremost symbols being two circles, a big one for the creator, the other for creation with no ontological bridge between." (James N. Anderson, "Obituary: Dr. Cornelius Van Til," www.vantil.info, April 18, 1987.) See also Frame, Van Til, 27; and Muether, Van Til, 116.
23. Anderson, "Obituary."
24. Van Til encountered Kuyper in his theology and religion classes at Calvin College in Grand Rapids, Michigan. Calvin College was founded by the Christian Reformed Church, which in turn has its roots in the Dutch Reformed churches. For Van Til's introduction to Kuyper, see Muether, Van Til, 44-46.
25. Muether, Van Til, 24-25; and Marsden, Reforming Fundamentalism, 78-79.
26. Muether, Van Til, 25.
27. Ibid., 25. As Muether explains, Kuyper believed that Christians and non-Christians can work together in spite of their irreconcilable worldviews because of the work of common grace. Since non-Christians can never be truly epistemologically self-conscious and ultimately rely on Christian presumptions, there is room for cooperation on projects designed to better the human condition. Van Til reformulated this view of common grace to argue that it provides a check on any "absolute expression" of human depravity in history. See ibid., 154-155.
28. Quoted in Roberts, "Van Til," 124.
29. R. J. Rushdoony to Lorna Logan, April 4, 1946, RJR Library.
30. 2 Corinthians 10:5.
31. See Rousas John Rushdoony, Intellectual Schizophrenia: Culture, Crisis, and Education (Phillipsburg, NJ: Presbyterian and Reformed, 1980) and Rushdoony, The Messianic Character of American Education: Studies in the History of the Philosophy of Education (Nutley, NJ: Craig Press, 1963).
Topics: Biography, Christian Reconstruction, R. J. Rushdoony