When René Descartes penned the words, “Cogito, ego sum,” he intended to set out on a course that would preserve the link between faith and reason, believing that by positing his subjective existence he could then provide a solid argument for the existence of God.1 He did not foresee that the “turn to the subject” that enabled him to provide a subjective, rationalist argument for the existence of God would also provide a means for others to undermine that existence and call it into question. H.D. Lewis notes that many of the assumptions in Descartes’ argument for an infinite being are problematic: “[H]e imports into his premises, at every step in an elaborate argument, certain considerations derived from the notion of an infinite being which it is the aim of the argument to defend.”2 Descartes attempted to construct a system of metaphysics,3 but his approach of halting the tide of skepticism with a system based on doubt and tainted, apparently, by circular reasoning inevitably opened the way to more skepticism.
Descartes’ strict separation of mind from body reversed the realist synthesis of material and spiritual in Aristotelian epistemology. While Descartes chose an idealist orientation, looking to the inner subjective experience and “the clear and distinct idea as the criterion of truth,”4 others (the British empiricists) took a more materialistic approach. Idealism predominated on the European content, while empiricism held sway in Britain and North America.
What distinguishes empiricism and rational idealism from the materialism and spiritualism of the Greeks is the subjective focus. Like Descartes, Plato believed in innate ideas. However, whereas Plato believed in a realm where ideas existed as objects, Descartes did not. Like the materialists of Aristotle’s time (and like Aristotle himself), the empiricists believed that we learn from our experience with material reality. However, rather than knowing the physical realities themselves, the empiricists believed that we only know and learn from our sense impressions, which they saw as fainter versions of those material realities. For John Locke, the closest we could come to knowing material reality would be to know “the nominal essence.”5 For David Hume, senses are lively perceptions and ideas merely weaker ones.6 While Locke still held to a belief in some kind of first cause, the “One Infinite Mind,” Hume viewed the prospect of such a being more skeptically.7 Hume even went so far as to dispute our ability to determine causality, opting for a weaker notion, causation, which would go “beyond the evidence of our memory and sense.”8
While Descartes continued to trust in reason and in the inner subjective experience as the source of truth, the empiricists trusted facts and observations, albeit as mediated through our subjective sense impressions. Clearly, if we can only know our world in a nominal way through sense impressions, the possibilities for knowing a Creator outside of time and the material world recede quickly.
While the empiricists focused their attention on the sense impressions and what these impressions tell us about the world in which we live, Immanuel Kant developed a form of idealism that focused on how we come to formulate knowledge about the world. He proposed that we have categories in our mind that we project onto sense impressions to come to an understanding about our world. Like Plato, he used the terms phenomena and noumena to describe appearances of things and their essences respectively. However, he denied that we can ever know the noumena or essence and granted that we can only use phenomena to attain valid knowledge.9 With no ability to know essences, we are locked into a world of subjective sense impressions, one in which we can only “know” our world in an internally consistent, albeit relative, way and one in which certain knowledge of God isn’t possible. William Wallace explains:
[M]etaphysics is a ‘transcendental illusion’ and any consideration of God, immortality, and freewill can only lead to antimonies, that is, to ultimate contradiction. Legitimate knowledge of the real world is reached by ‘the secure path of science,’ the path already charted by a mathematical physics like that of Newton.10
Wallace notes that this principle resounds, predictably, with empiricists and positivists. On both extremes, the “turn to the subject” results in a science that is, at best, agnostic and incapable of addressing anything beyond material existence.
While the modern science of nature has given mankind greater insight into the mechanics of nature, it has no response to the question of first causes. Because matter is the focus of its enquiry, it cannot respond to the origin of matter. Its very foundations limit its application to that which can be known through the senses, which by definition are material realities. Any reality beyond matter or responsible for matter is already outside of its realm of study.
Modern philosophy, in itself, has little more to offer us if we wish to understand the Creator and His creation. In large, philosophy has been reduced from the overarching science of being as being to very specialized analyses of language. Poststructural criticism in particular (for example, deconstructionism) creates more questions than it answers about our ability to communicate meaning. The modern turn to the subject, then, has resulted in a philosophy of subjective isolation and a science of nature in which events can be predicted but for which acquisition of meaning is postponed.
The problem with modern philosophy is not with its consideration of the subject but with its abandonment of the object. While the Renaissance scientists were correct to reject the specifics of Aristotle’s science, they abandoned that which was critical for an integrated epistemology—trust in the ability of reason to analyze sense data, to come to an understanding of material existence, and to transcend existence to come to understand essence. If we have no means for finding the essence of material being, we cannot hope to attain knowledge of the One in whom existence and essence are the same.
Popes Leo XIII and John Paul II both recognized a need to turn back to the object and proposed the thought of St. Thomas Aquinas as the ideal starting point. This challenge has been taken up by theologians such as Karl Rahner, but other Catholic mystics and thinkers, such as St. Teresa of Avila, have recognized the need for a synthesis of idealism and materialism. We cannot dispense with science, but we must also understand that much valid knowledge is accepted on faith. Faith and reason cannot be in contradiction and are complementary in the work of theology. While only God’s grace can help us to have faith, reason (as demonstrated by St. Thomas’s five proofs) can help us to dispel doubt and open ourselves to the possibility of faith.
Lewis, Hywel D. “History of Philosophy of Religion.” Encyclopedia of Philosophy. 8 Vols. New York: MacMillan Publishing, 1967.
Morris, William Edward. “David Hume.” Stanford Encyclopedia of Philosophy. Ed. Edward N. Zalta. Spring 2001
William A. Wallace, O.P. The Elements of Philosophy: A Compendium for Philosophers and Theologians. New York: Alba House, 1977.
William A. Wallace, O.P. The Modeling of Nature. Washington D.C.: Catholic University Press, 1996.