In the history of Western philosophy, the focus has been on the nature of reality (metaphysics); yet, modernistic philosophies began to focus on epistemology, instead. The term “onto-theology” dates to Martin Heidegger’s 1936 lectures on Friedrich Schelling. Here, the expression signifies a “presupposition that there is an analogy of being between our philosophical ideas about (the structures of) the world as such and God as its absolute ground.” As Merold Westphal defines it, “Each [form of onto-theology] puts its God, whether it be the Unmoved Mover, or Nature, or Spirit, or the Market to work as the keystone of a metaphysical theory designed to render the whole of reality intelligible to philosophical reflection.” He decries the practice, writing, “Philosophy makes the rules that God must play by.” For Heidegger, the question of ontology (“being”) was the most important question in philosophy, but he objected to conceptualizing “being” from only one outlook (e.g. Platonic “forms” or Ideas). Hence, Heidegger became the defining voice of opposition against onto-theology.
From the postmodern perspective, classical theology is beleaguered with the concept that reality possesses an objective and universal meaning. Throughout church history, theologians have engaged in onto-theology by attempting to provide a comprehensive ontological account of the world. The underlying precept is a “metaphysics of presence,” which denotes the conviction that an ontologically transcendent element is continually present within reality. In other words, theologians have traditionally presumed the presence of an identifiable divine agent, who has imbued theological sources with an objective monosemous quality. Thus, onto-theology equates divinity with “being” itself, viewing God as merely one being among many. Accordingly, God becomes the “transcendental signified,” who “functions as the purported locus of truth that is supposed to stabilize all meaningful words.”
Effectively, onto-theology and the metaphysics of presence represent an epistemological claim to incorrigible knowledge about God, intending to answer all theological questions. They epitomize modernity’s overconfidence in the ability to articulate accurate and systematic information about the divine. “Onto-theology is characterized by calculative and representational thinking that eliminates God’s transcendence, [and] puts the divine at the disposal of human knowledge.” Consequently, as a pejorative term, “onto-theology” conveys the perceived problems of comingling God and Western philosophy, which has arrogantly attempted to eliminate divine mystery and transcendence. As Westphal clarifies, “Perhaps onto-theology consists in the pride that refuses to accept the limits of human knowledge.”
In terms of theological pronouncements, the mimetic notion of truth is intrinsic to onto-theology and its philosophical conjectures. Contrary to purely propositional formulations, mimesis utilizes the verisimilitude of human conceptualizations in order to generate a representational understanding of the divine that is both firsthand in its proposed knowledge and universal in application. Millard Erickson summarizes this position, “There is believed to be a real given that is present in our intellectual system, and that this is before and independent of language and thought about it. Western modernism believes that it so accurately captures and depicts this given that it can be said virtually to reflect it. This is the mimetic view of truth, which [Jacques] Derridá and other deconstructionists attack.”
Metaphysically, this conceptual truth perceives God as pure “being,” which normalizes and tempers the divine nature to a reductionistic, solitary characteristic. According to Heidegger, Western philosophy absorbed Platonism’s preoccupation with articulating the essence of “being,” which became the defining presumption of later theology and apologetics. Hence, the mimetic systematization of God relies on philosophical conjectures about metaphysics. Expressed differently, onto-theology desires to transcend human limitations by discerning the mysteries of God. As George Pattison explains,
Metaphysical thinking is thinking that offers an account of all that is and does so by tracing this ‘all’ back to its most basic ground, to what makes it be what and as it is, its first cause, or ultimate reason or ratio. This means that it can be described as onto- … because it views the world with regard to its being, theo- … because it deals with the ultimate cause of the world, and ‘logical’ because it offers an account or discourse … of its subject matter.
This modernistic system seeks to establish theology based on “second-order” rationalistic grounds rather than appealing to faith in divine self-revelation.
Ultimately, onto-theology is merely the Hellenization of Christian faith where modernists seek to conceive of God in Greek classifications of “being,” thereby transforming the biblical God into a philosophical deity. This duality of ontology and theology persists because of Western philosophy’s metaphysical fixation on expounding the nature of reality. Traditional metaphysics attempts to combine Greek ontological speculations with theology and, therefore, conceives of God as causa sui. Apologetically, onto-theology seeks to prove the existence of God using philosophically grounded rational proofs, creating an endless reciprocity of entities justifying each other’s existence. God is the “ground of all being,” having created other beings, and yet receives this description only as created beings conceptualize God philosophically.
Onto-theological conceptions have important repercussions for apologists by demanding that they accede to the theistic proofs of rational scholasticism. Instead of promoting dialogue among different faiths, perspectives, and interpretations, onto-apologetics necessitates a positive and overconfident defense of an exclusive onto-God. According to postmodernists, onto-theology transforms apologetics into an obstinate ideology, relying on Enlightenment ideals of reason, evidence, and debate to provide apologists with self-assurance and superiority. The assumption for onto-apologetics is that God necessarily becomes “the ultimate metaphysical principle” from which to explain everything else about the world.
 J. Aaron Simmons and Bruce Ellis Benson, The New Phenomenology: A Philosophical Introduction, Pbk. ed. (New York: Bloomsbury Academic, 2013), 58-59; Laurence Paul Hemming, “Nihilism: Heidegger and the Grounds of Redemption,” in Radical Orthodoxy: A New Theology, ed. John Milbank, Catherine Pickstock, and Graham Ward (New York: Routledge, 1999), 95. See also, Martin Heidegger, Identity and Difference, trans. Joan Stambaugh (1969; repr., Chicago, IL: University of Chicago Press, 2002), 42-74 and Sebastian Gardner, “Sartre, Schelling, and Onto-Theology,” Religious Studies: An International Journal for the Philosophy of Religion 42, no. 3 (September 2006): 247-71. Heidegger explained, “When metaphysics thinks of beings with respect to the ground that is common to beings as such, then it is logic as onto-logic. When metaphysics thinks of beings as such as a whole, that is, with respect to the highest being which accounts for everything, then it is logic as theo-logic” (Heidegger, Identity and Difference, 70-71).
 Peter Jonkers, “God in France: Heidegger’s Legacy,” in God in France: Eight Contemporary French Thinkers on God, ed. Peter Jonkers and Ruud Welton, vol. 28, Studies in Philosophical Theology (Leuven, Belgium: Peeters Publishers, 2005), 6.
 Merold Westphal, Transcendence and Self-Transcendence: On God and the Soul (Bloomington, IN: Indiana University Press, 2004), 18.
 Ibid., 34.
 Christina M. Gschwandtner, Postmodern Apologetics? Arguments for God in Contemporary Philosophy, Perspectives in Continental Philosophy (New York: Fordham University Press, 2013), 19-20.
 Stanley J. Grenz, A Primer on Postmodernism (Grand Rapids, MI: William B. Eerdmans Publishing Company, 1996), 138-50; Millard J. Erickson, Postmodernizing the Faith: Evangelical Responses to the Challenge of Postmodernism (1998; repr., Grand Rapids, MI: Baker Books, 2002), 86.
 See the entire discussion in Jacques Derrida, Of Grammatology, trans. Gayatri Chakravorty Spivak (1976; repr., Baltimore, MD: Johns Hopkins University Press, 2016), 47-70 and Gschwandtner, Postmodern Apologetics, 21. Cf. Anthony C. Thiselton, New Horizons in Hermeneutics: The Theory and Practice of Transforming Biblical Reading (Grand Rapids, MI: Zondervan Publishing House, 1992), 83.
 Mark C. Taylor, Erring: A Postmodern A/theology, Pbk. ed. (1984; repr., Chicago: University of Chicago Press, 1987), 105; emphasis in original.
 See Craig A. Baron, “The Theology of Gerald O’Collins and Postmodernism,” American Theological Inquiry 2, no. 1 (January 2009): 18; Westphal, Transcendence and Self-Transcendence, 15-90; and Erickson, Postmodernizing the Faith, 127-44.
 Gschwandtner, Postmodern Apologetics, 239. See also, Westphal, Transcendence and Self-Transcendence, 21.
 Gschwandtner, Postmodern Apologetics, 21, 29, 237-41; Simmons and Benson, The New Phenomenology, 89-98. As Christina Gschwandtner remarks, “Preserving God’s transcendence in an acknowledgment of the limitations of our knowledge of the divine is an important (if not the central) aspect of the postmodern faith” (Gschwandtner, Postmodern Apologetics, 237).
 Merold Westphal, Overcoming Onto-Theology: Toward a Postmodern Christian Faith (New York: Fordham University Press, 2001), 7.
 Cf. Stephen Prickett, Words and The Word: Language, Poetics and Biblical Interpretation (1986; repr., New York: Cambridge University Press, 1989), 4-36 and Erich Auerbach, Mimesis: The Representation of Reality in Western Thought, trans. Willard R. Trask (1953; repr., Princeton, NJ: Princeton University Press, 2003), esp. 143-73.
 Erickson, Postmodernizing the Faith, 107; italics in original.
 See Adriano Alessi, “L’essere e la crose. Dibattito sul’ ‘onto-teologia’,” Salesianum 52, no. 1 (1990): 53-111 and Simmons and Benson, The New Phenomenology, 142.
 George Pattison, God and Being: An Enquiry (New York: Oxford University Press, 2011), 17-55. Heidegger referred to this preoccupation as the “onto-theological constitution of metaphysics” (Heidegger, Identity and Difference, 42-74).
 Pattison, God and Being, 5.
 Merold Westphal characterizes the kerygmatic dogmas of Christian faith, such as those found in orthodox creeds, as “first-order Christian discourse.” See the entire discussion in Westphal, Overcoming Onto-Theology, xii-xvi.
 See Brian D. Ingraffia, Postmodern Theory and Biblical Theology: Vanquishing God’s Shadow (New York: Cambridge University Press, 1995), esp. 101-22, 226. It should be noted that while Brian Ingraffia objects to onto-theology as a method for constructing biblical theology, he does not endorse postmodernism in its entirety. For a detailed discussion on deconstruction’s relationship with onto-theology, see Henry L. Ruf, ed., Religion, Ontotheology and Deconstruction (New York: Paragon House, 1989).
 Martin Heidegger, “Kant’s Thesis about Being,” in Pathmarks, ed. William McNeill, trans. Ted E. Klein Jr. and William E. Pohl (1967; repr., New York: Cambridge University Press, 1999), 340.
 Gschwandtner, Postmodern Apologetics, 20, 28-29; Heidegger, Identity and Difference, 58-60. For an example of using philosophy (detached from special revelation) as a theistic proof, see William Lane Craig, Reasonable Faith: Christian Truth and Apologetics, 3rd ed. (Wheaton, IL: Crossway Books, 2008), 111-52 and “Classical Apologetics,” in Five Views on Apologetics, ed. Stanley N. Gundry and Steven B. Cowan, Counterpoints: Bible and Theology (Rapids, MI: Zondervan, 2000), 48-53.
 Erickson, Postmodernizing the Faith, 130-31.
 John Sanders, “Historical Considerations,” in The Openness of God: A Biblical Challenge to the Traditional Understanding of God, by Clark Pinnock et al. (Downers Grove, IL: InterVarsity Press, 1994), 63-64.