Descartes` Method Of Radical Doubt: Causes And Consequences

The Cartesian Revolution

Rene Descartes (d.1650 AD) is often referred to as the father of modern philosophy with good reason. Through his writings in Meditations, Descartes ushered in an era of radical doubt that led to a questioning of the unquestionably, including the tenets of Christian religion upon which European civilization was built. While he is best known for his conception of dualism, dividing the world into res extensa (material reality) and res cognitans (mental reality), this was a conclusion reached through a specific programme of doubt, that itself had more impact than the aforementioned dualism. Central to Descarte s method was the notion of starting from first principles, erasing the pre-conceived notions and attempting to conceive of a coherent order after rendering his mind a completely blank state this was done in a precautionary attempt to avoid the trappings of unthinking falsehood, as, if everything is doubted, everything can be proven or disproven. In Meditations I, Descartes opens with an introspective reflection detailing why he embarked down this path of doubt:

It is now some years since I detected how many were the false beliefs that I had from my earliest youth admitted as true, and how doubtful was everything I had since constructed on this bases: and from that time I was convinced that I must once for all seriously undertake to rid myself of all the opinions which I had formerly accepted, and commence to build anew from the foundation, if I wanted to establish any firm and permanent structure in the sciences now for this object it is not necessary that I should show that all of these are false I shall perhaps never arrive at this end. But insomuch as reason already persuades me that I ought no less carefully to withhold my assent from matters which are not entirely certain and indubitable than from those which appear to me manifestly to be false, if I am able to find in each one some reason to doubt, this will suffice to justify my rejecting the whole. [1]

Descartes even doubted his own existence in arriving at his first principle, from which his famous statement, cogito, ergo sum (I think, therefore I am), emerges. Starting with no assumptions whatsoever, Descartes saw fit to question if it was possible that he did not exist at all, and came to the conclusion that, because of the very fact that he was thinking such a thought, he must necessarily exist in order to think it. This is a reflection that emerges from his understanding, present in the Discourse, that human beings are thinking substances the fact that he is thinking is evidence for the fact that he is an existing human being. Intimations of dualism are then seen in the subsequent passages, wherein Descartes doubts whether or not the Cogito is correct based on sense-data: he, like al-Ghaz l (d. 1111 AD), speaks of the unreliability of the senses, though rather than employing the metaphor of the feverish patient who perceives a non-existent heat, he speaks of the duplicity of dreams, wherein he believes himself to be sitting dressed nearby a fire only to awake undressed in bed.

Still an heir to the pietistic philosophers of medieval Europe, Descartes then turned his method of doubt to the question of God s existence, albeit in a different manner rather than starting with the conclusion that God exists and exploring philosophy as an investigation into the necessary outcomes of His existence, Descartes viewed God as the possible solution to the aforementioned puzzle of the senses. For Descartes, nought could establish the veracity of the senses save for the beneficence of God. It could be, as Descartes entertained, that there was no God, or that there was instead a supremely powerful being of equal omnipotence singularly concerned with employing his unlimited power to deceive poor Descartes into thinking that there is such a thing as the outside world. He argues that, on the basis of human reason applied to necessarily true propositions like that of ergo cogito sum, such a malevolent spirit would not be able to deceive him entirely, and thus, the existence of human intellect is proof for the beneficence of God.

It is not, however, his only proof, and he sees fit to expound on the reasons why he believes in a God that guarantees the trustworthiness of the senses. His proof of God, often referred to as the Ontological Proof for God s existence, lies in the understanding of God as a perfect being. For Descartes, the fact that he has an idea within himself of perfect being is evidence that such an idea was imparted onto him by said perfect being. Other ideas, like those of other men or animals, can be formed by an admixture of the other ideas which I have of myself, of corporeal things, and of God, even although there were apart from me neither men nor animals nor angels, in all the world. However, as for God, he writes:

By the name God I understand a substance that is infinite, independent, all-knowing, all-powerful, and by which I myself and everything else, if anything else does exist, have been created. Now all these characteristics are such that the more diligently I attend to them, the less do they appear capable of proceeding from me alone hence, from what has been already said, we must conclude that God necessarily exists. [2]

Descartes continues this line of reasoning by further exploring the notion of perfection: for Descartes, to be perfect entails existence a being that does not exist would necessarily be inferior to one that is and so, if we define God as the perfect being, God must exist, as otherwise he would not be the perfect being. Thus, with the existence of God established, and subsequently, the veracity and trustworthiness of the senses guaranteed by the perfect being, Descartes turns his method of doubt to the observable world, wherein his understanding of matter as res extensa is expounded.

The Origins of Dualism

Descartes, now endowed with the ability to trust his eyes and ears and a belief that the intellect is a divine gift in deciphering sensory data, turns his method of doubt to the question of whether material things exist. Already confirming the existence of purely mental concepts such as the objects of pure mathematics, Descartes affirms the often-duplicitous nature of the senses, and speaks of their deceits a distant tower may appear to be round, when it is in fact square in shape but, when considering his own body, realizes the truth of corporeal existence, from which we see his theory of man as the intersection of the material and the spiritual emerge. Writing the following, he expounds on how he reached this conclusion:

Nature also teaches me by these sensations of pain, hunger, thirst, etc., that I am not only lodged in my body as a pilot in a vessel, but that I am very closely united to it, and so to speak, intermingled with it that I seem to compose with it one whole. For if that were not the case, when my body is hurt, I, who am merely a thinking thing, should not feel pain, for I should perceive this wound by the understanding only, just as the sailor perceives by sight when something is damaged in his vessel. [3]

That Descartes doubts regarding his own body are quelled thus necessarily leads to the extension of that principle to bodies other than his own, which, through the senses, he has established to be truly existent. He conceives of bodies, or matter, as possessing the essential quality of extension, and from this induces a secondary proof for God s existence: by saying that bodies are necessarily extended, we must also say that God is necessarily existent for Descartes, the non-existence of God is as implausible as a body that does not extend across three-dimensional space. Furthermore, he distinguishes between the body as always divisible, compared to the entirely indivisible mind a foot or a hand can be removed from the body, but nothing can be removed from the mind. As one turns the pages of Descartes Meditations, it becomes readily apparent how the foundations of his dualism are being laid.

Through these reflections, Descartes method of doubt leads to the conviction that there are two unassailable truths: that first, the essence of matter is extension in motion, and secondly, the essence of the mind is thought. These two realms, for Descartes, are mutually exclusive: the mind cannot extend through space, nor can material things truly think only in the Adamic miracle of humanity can the oceans of mind and matter intermingle. There are a number of secondary and tertiary implications to Descartes thoughts reflected in Meditations as well: most importantly, the sensory organs, while to be largely trusted due to the beneficence of God, are not the primary pathways to truth: he admits that while he can indeed grasp the primary qualities of the material world, its secondary qualities and attributes lie beyond his grasp. For Descartes, the senses exist to facilitate our worldly existence, not directly lead to metaphysical truths that is the role of the mind. The mind can indeed err, but this is not a reflection of a deceitful God rather, it arises only because of the infirmity of human nature.

Context of Descartes

This Cartesian theory of dualism emerged in the context of the changing world of the seventeenth century, wherein the theologian-philosopher of the medieval ages gave way to the enlightened laity. His life was marked by a certain disregard for traditional scholarship, such that he boasted that he had not opened a scholastic textbook once in twenty years he conceived of himself, in a very modern fashion, as reinventing philosophy itself, rather than being a mere continuation of the Platonic and Aristotelean tradition distilled through the lens of Christianity. For Descartes, knowledge emerged foremost from reflection, then from experience, and finally from the study of texts. Descartes was no doubt influenced by the controversy surrounding Galileo s (d. 1642) heliocentrism, and although he agreed with the Copernican conception of the universe, he did not publish his astronomical works for fear of censure a fact that would lead to considerable resentment against the scholarly status quo. This was not without just cause, as, following the publications of the Meditations, accusations of heresy were hurled at him according to Kenny, were it not for his friendship with a certain Princess Elizabeth of Bohemia (d. 1662) and other influential figures, he too would have had his books burnt.

Thus, Descartes method of doubt can be seen as a continuation of what emerged of humanism in the sixteenth century. He was not the first thinker to find himself labelled as a heretic by the powers at hand, nor was he to be the last: the Protestant reformation and the internecine wars to follow sparked a wave of independent thought throughout Europe, and accordingly, violent reactions against it. Notably, the re-emergence of Greek scepticism through the discovery and publication of Sextus Empiricus (d. 210 AD) works by Michel Eyquem de Montaigne (d. 1592 AD), led to philosophers daring to step outside of the bonds of Church-sanctioned Aristotelean philosophy. Notably, the Italian philosopher Giordano Bruno (d. 1600 AD), found himself roasted on the inquisitor s pyre for his heterodox thoughts. All of these thinkers, though themselves not humanists insomuch as the word is understood today, contributed to a trend in which more and more of that which was hitherto unquestionable was called into question.

The dualism of Descartes, born of the epistemological uncertainty of the past century, was an important stepping-stone on the path to Spinoza s famous critiques of the Bible. For the first time, the European mind conceived of a world in which the spirit was entirely divorced from the world, and as such, liable to relative negation. He shifted the conversation from one of truth as imposed on men by the external authority of God, to an anthropocentric focus on certainty. The intellectual agency of the human being now, rather than God, was to form the epistemological basis for all knowledge to follow, and indirectly, truth was confined to what was observable and discernible to the human intellect, from which God slowly became excluded. In the century to follow, Sir Isaac Netwon s (d. 1726 AD) three laws of motion further cemented this, as the world of matter became increasingly mechanistic to the exclusion of the immaterial world. Descartes set out, in his method of radical doubt, to reinvent the very conceptual framework of philosophy, and it can be said that he indeed succeeded, although he in no way foresaw how his thoughts would be used to usher in the new post-Christian order.

[1] Descartes, Rene. 2019. Meditations On First Philosophy. Lanham: Dancing Unicorn Books. 6.

[2] Ibid, 16.

[3] Ibid, 29.