Descartes’ Method: Rules for Philosophical Inquiry
Descartes’ Rules for Philosophical Method
In the second part of his book, Discourse on Method, René Descartes summarized the method of his new philosophy in four rules. The first relates to intuition, while the other three pertain to deduction.
1. The Rule of Evidence and Doubt
This rule states: “Do not accept as true but what is obvious.” It is the first and most important of the method’s rules. It dictates accepting as true only what is presented clearly and distinctly, that is, with evidence. This is the exercise of intuition.
This rule gives rise to methodical doubt, and through its application, knowledge or learning becomes a strict science. Descartes tells us that we will never be misled if we limit our judgments only to what we know clearly and distinctly. Error originates when we judge before having accurate knowledge of the matter. The will, which is essential to give our consent to a judgment, can go beyond what is offered with clarity and distinction, and therefore lead to error. Descartes believed that if we err, it is due to the wrong use of our will.
2. The Rule of Analysis (Resolution)
Analysis (or resolution) is a research method that involves dividing each difficulty we encounter into as many parts as possible to arrive at the simplest elements. The truth of these simplest elements can then be established by an act of intuition.
Its purpose is to break down the complex into its constituent elements, allowing us to reach simple natures. With this method, we can understand more obscure propositions by observing how they depend on simpler ones. Descartes states in the Meditations that this is also a good teaching method because it shows the way by which a thing was methodically discovered. It is still used to demonstrate the truth of complex sentences (e.g., the mind is distinct from the body, the mind can exist without the body, God exists).
In this work, the elementary proposition arrived at by analysis, and from which, later and through a process of synthesis, the truth of the more complex propositions above can be proven, is the cogito, whose truth is shown by intuition.
3. The Rule of Synthesis (Composition)
Also known as the method of composition, this rule involves ordering our thoughts, moving from the simplest and easiest objects to learn towards the knowledge of the most complex and obscure.
In the Discourse on Method, Descartes presents it as the third rule. It recommends starting with first principles or intuitively perceived simple propositions (which are reached by analysis) and proceeding to deduce other propositions in an orderly manner, ensuring not to skip any steps and that each new proposition truly follows the precedent. This is the method used by Euclidean geometry.
According to Descartes, while analysis is the method of discovery (used in the Meditations and the Discourse on Method), synthesis is the most appropriate method to demonstrate what is already known, and it is employed in the Principles of Philosophy.
4. The Rule of Enumeration and Review
This rule involves carefully reviewing each step that constitutes our research to ensure nothing has been missed and no errors have been committed in the deduction.
Part Four: Descartes’ Philosophy and God’s Existence
Part Four is the central chapter of Descartes’ Discourse on Method, where he creates a new philosophy and establishes its first principle: “I think, therefore I am.” From this first principle, Descartes establishes the existence of God.
Arguments for God’s Existence
1. Argument from Imperfection
The first argument given to justify the existence of God is that if we are aware of our imperfect nature, it is because we know what perfect nature is.
2. Argument from Self-Creation
The second argument for God’s existence is based on our own imperfection. If we, who understand perfection, had the power to create ourselves, we would have made ourselves perfect. Therefore, our being requires a creator who possesses these perfections, namely God, from whom everything depends and without whom nothing could exist.
3. Ontological Argument
The last argument given to justify the existence of God is that God, understood as perfection, is as great as one can conceive. God must exist (this is the “ontological argument,” taken from Saint Anselm) because if not, one could conceive of something more perfect, and that would then be God.
The existence of God, in turn, demonstrates the existence of the world. For God, being infinitely good and true, cannot allow us to be deceived into believing that the world does not exist, just as God guarantees the clarity and distinctness of our ideas.
However, Descartes ultimately states that, even taking the above into account, it is our duty, not God’s, to free ourselves from illusions and avoid mistakes.