Rationalism: Descartes, Spinoza, and Leibniz
Rationalism
Rationalism holds that the source and origin of knowledge is reason. It is knowledge that is valid and real, clear and distinct reason, and comes from no sense. The model of rational knowledge is the deductive system of mathematics, where all knowledge is inferred from first principles or ideas.
1. Descartes
In 1637, he published the Discourse on Method. In his address, he outlined his method (theory about how the pursuit of knowledge) and a first outline of philosophical knowledge that this method has paid off with (metaphysical).
1.1. The Method
Human reason is a valuable and effective tool. According to Descartes, science has a method that allows security in knowledge, but philosophy lacks a proper method. Descartes introduces a mathematical method in philosophy to provide human reason a criterion of truth, final and unappealable. Descartes sees mathematics as a rational science that brings order to the chaos of data that gives us experience. In the Discourse on Method, 1637, Descartes establishes the four fundamental rules of his method: the evidence (intuition), the analysis, the synthesis, and the enumeration.
1.2. Doubt and the First Truth
Descartes made a radical critique of all knowledge and considers all knowledge unreliable. It is his famous universal doubt and methodically based on the following reasons:
- The uncertainty of sensory data. Descartes doubts all data that originates in the senses.
- The errors of reasoning. Traditional knowledge is based on scholastic reason and discursive power in us, but at the time of Descartes, this knowledge has become confused and uncertain.
- The difficulty in distinguishing sleep from wakefulness. According to Descartes, there is a possibility that all thoughts of waking dreams are really not recognized as such.
- The hypothesis of the evil genius. Existence of a <> which leads to consider as obvious things are not.
Cartesian doubt is beyond doubt: it auto-supersedes. Let this self-improvement: when I doubt, I think, and the action of thinking implies the existence of a thinking being. If I’m thinking, then I’m there too: I think, therefore I am (<>), this will be the first unquestionable truth to which Descartes accesses. It is an intuition: absolutely no reason to doubt it is evident, clear, and distinct. The cogito ergo sum fulfills two well-defined functions:
- Justifies the existence of a thinking self differentiated from the body. The body, perceived through the senses, is under methodical doubt.
- It becomes a model principle. All that is obvious, clear, and distinct as the first principle will be accepted as truth.
1.3. The Three Substances
Using his method, Descartes distinguishes the three substances that make up the totality of what is real.
1.3.1. The Thinking Self
Universal methodic doubt has led to an undeniable reality: the existence of a thinking self, i.e., a substance that thinks, a res cogitans, a soul. Descartes concludes that I doubt the existence of my body and the world around me because I have information through the senses and the senses are unreliable, but I cannot doubt the existence of my thoughts, my ideas, my subjectivity. Subjectivity is a collection of thoughts, ideas, and representations that flow in my self. For Descartes, the big challenge is finding a way of knowing that my ideas about the world are not dreams or illusions, i.e., whether there are objective things as these things go. I think the different ideas, Descartes are studied and classified.
- Adventitious or acquired. These are the ideas that come from outside of sensory experience, my perception of the world, or teaching. These ideas might be wrong because we often have different ideas on the same external object.
- Factitious. These are the ideas that we invent or we make ourselves arbitrarily. The idea of a mythological animal.
- Innate or natural. These are the ideas that emerge from the very faculty of thinking. These are ideas that capture our minds and must necessarily accept without being able to change anything. The idea of God, the idea of cause, substance, or number.
1.3.2. God
The thinking I have the idea of perfection, the idea of perception is innate in us the idea of a perfect being: the idea of God. This idea of perfection or God cannot come from us, imperfect beings, therefore, must have been a divine reality which has given rise in our minds. Among the ideas that have the thinking self, sobresale a very privileged, an idea that can go beyond one’s own subjectivity. One idea to suggest, clearly and distinctly, that outside of myself, out of my mind, there is a reality, an extra-mental reality. It is the innate idea of God. Outside of myself, there is another reality, the perfect substance, a being who cannot let my clear and distinct ideas are a hoax. God becomes a guarantee of knowledge. In God, there are the great eternal truths established by Him; all mathematical truths that are found in God, the laws of nature are ordained by God. In his argument for the existence of God, Descartes incorporates the former St. Anselm’s ontological argument for Descartes ideas have an undeniable fact. The idea of God is inseparable from his vast property, existence. In this perfect being cannot miss him as a perfection is existence.
1.3.3. The World
Doubt has enabled Descartes to affirm the existence of a first substance, the thinking self, and this reveals a second substance, God, being with all perfections, including truthfulness. My self is fully aware of the difference between the idea of thinking self and the idea of extended body. It has the clear and distinct idea of the thinking self and not extensive and, on the other hand, has the clear and distinct idea of the extended body and unthinking. From thinking I cannot doubt; the body, yes. But if I have a clear and distinct idea of my body and there is extensive and accurate a perfect God, the God who created me rational, cannot allow myself to cheat when I make proper use of my reason. The goodness of God guarantees that the natural human tendency to believe in the existence of extended things is not misleading. Besides thinking substance, there is another type of finite substance and created: the bodies, all with a fundamental attribute, extension. The matter or res extensa is the third substance of Cartesian metaphysics.
1.4. Freedom and Mechanism
Descartes’ reactive anthropological dualism (body/soul), the main reason is to defend human freedom. The body as a whole extended thing, as all matter is governed by mechanical laws that determine it. If I was not thinking a substance completely separate and detached from the body, there would be no place for freedom. The soul is a substance that in no way can be subjected to mechanical and deterministic laws governing the body. The mechanism that emerges from the anthropological dualism (according to which the soul is free and the body is determined by mechanical laws) had implications for all types. On the one hand, the search stimulus biological, physiological, and medical. On the other hand, if all matter and all nature are considered a machine, nature and disposition are at the service of man.
2. Spinoza
2.1. Rational Spirit
Spinoza’s philosophy is inspired by modern rationalism. Spinoza used to develop a mathematical method that unfolds deductive way. Mathematical deduction is considered the highest form of rationality. Is rationality that allows us access to more rigor into reality. His most important work, According to Proven Ethics Geometric Order, is structured like any other treaty of geometry: first establishes definitions, sets below a series of axioms (statements which the author believes that require no demonstration because they are considered obvious), and from the definitions get different axioms and propositions or theorems whose truth is demonstrated by applying deductive logic. In the propositions that will follow will demonstrate various corollaries or conclusions we can draw from them. The expository of Spinoza is genuine knowledge, knowledge by causes. Follows a logical order that goes from the universal to the particular. The exposition of Spinoza has a strong and leaves no one indifferent.
2.2. Substantial Monism: Substantia sive Deus sive Natura
Spinoza starts from the Cartesian definition of substance; the substance was a reality that exists so that it needs no other reality to exist. Spinoza concludes that there is only one substance, God. This unique substance, God is identified with nature, Deus sive Natura (God or nature). This reality that we call God or nature is infinite and has infinite attributes. Spinoza distinguishes between natural and unnatural naturans naturata:
- The nature naturans is the creative nature, i.e., God as infinite substance and cause of everything.
- The nature naturata is created nature, the set of all existing individual realities.
Individual realities are forms of God, finite expressions of God’s infinity. Spinoza explains that creation is a natural necessity. But despite being a necessary act of creation, this does not mean that God is not a free man: God creates freely.
2.3. Ethics and Happiness
Spinoza reviews the anthropological dualism. We are soul and body; they can only know these two attributes of God because they are the only ones of us involved. Man tends by nature to persevere in being. It’s called the law of conatus. He seeks not only to survive but to achieve the peace of mind through proper knowledge. Virtue is to live under the guidance of reason, namely knowledge, exceeding our own passions in order to obtain what is most useful for us to do our conatus (preserved and perfected, thus increasing our power to act), i.e., what is best for our nature. The key to a happy life based on our understanding have adequate ideas, happiness is linked to understanding, for this is that we can free from the passions that try to dominate and submit, trying to go to Puerto equivocados. Spinoza called beatitude or intellectual love of God to see the world as an expression of eternity and infinity of God (sub specie aeternitatis), is when your mood is leading under the right ideas. Our victory over the affections and passions sad cannot come from its elimination, but that will come in the weakening, neutralization, and replacement by other conditions of opposite character. It is noted that there is no point lamenting the inevitable and that everything has its reason that we deem to be, i.e., is not contingent but necessary.
2.4. Freedom
For Spinoza, man is free when he understands the nature of things and accepts it.
3. Leibniz
3.1. Theory of Knowledge
Leibniz accepts the existence of innate elements, like the idea of God, the practical principles of moral order, the first logical and mathematical principles, certain impulses, and tendencies. A contribution of Leibniz is the distinction of two kinds or types of truths. For him, human knowledge consists of two kinds of truths:
- Truths of reason. They are analytical truths; the subject contains the predicate.
- True indeed. Truths are synthetic; the predicate is not apparent from an analysis of the subject but the observation of facts or empirical data.
For Leibniz, the world of logical consistency is different and distinctive in the world of things.
3.2. Monads
For Leibniz, what makes up the reality is much more than extensions, is dynamic, strong. Below pure extension, there are some energy points. These energy points called Leibniz’s monads (from the Greek monas “unit”). The monads are the elements which compose reality. There are an infinite number of monads, each one is pure energy, without parts, unextended, indivisible, and independent.
3.3. Pre-established Harmony
Leibniz asserts that God, in creating each unique cute, gives its internal law so that all act according to the harmony that is found throughout the cosmos and has been predetermined by God.
3.4. The Problem of Evil
To respond to the undeniable existence of evil in the world, which is discussed in Leibniz evil, and reach three types of evil: metaphysical, physical, and moral. Metaphysical evil is identified with the limitations of any reality other than God, is the absence of divine perfection. Physical evil (poverty, diseases…) is the lack of assets (prosperity, health), has no independent reality, is only the absence of good. The moral evil or sin comes from a quality or perfection granted by God to human beings: freedom. Leibniz concludes that, when the creation of the universe God has chosen to create this world and not another is because this is the best of all possible worlds.