Key Concepts in Cartesian and Spinozian Philosophy
René Descartes
Method: A set of safe and simple rules that serve to guide reason and allow its proper use. In the Discourse on Method, these rules can be reduced to four.
Evidence: The clarity and distinction with which certain ideas are held by our mind. An idea is clearly known if present and expressed with a sharp mind and taken with distinction if it is as accurate and different from all others that it cannot be confused with any other.
Innate Ideas: Those ideas that do not emanate from sensory experience but reason itself, in the sense that this is the bias or natural capacity to know (not because he is given a perfectly and distinct from childhood). For Descartes, only this kind of thinking is clear and distinct and, therefore, a principle of true knowledge.
Methodological Doubt: Doubt that Descartes proposed as an indispensable means to achieve absolute certainty. It is methodical because it served to test sentences that wanted to show with the intention of putting them on purely rational grounds. This doubt is universal, voluntary, and temporary.
Substance: The thing that exists so that it needs no other to exist. As this definition is only strictly applicable to God, Descartes added that the self and the world are also substances because, except for God, they do not need to exist in anything other than themselves.
Attribute: Essence or nature of each substance. The attribute of the thinking thing is thinking, and of the extended thing, extension. Both attributes are distinguished perfectly, and thought can conceive without any extension, and the extension can exist independently of thought.
Mode: That property that is not essential for the substance and may vary. Therefore, while it is not possible to distinguish between the substance and its attribute, we must affirm that a way is not identical with the substance and it needs it to exist. Modes of extended substance are the figure, the position, and movement. Similarly, modes of thinking substance are love, hate, judgment, etc. For Descartes, there can be no modes of God, for He is not subject to variation.
Primary Qualities: Properties of bodies referred to two modes of extended substance: figure and movement. Descartes considered that they are objective realities, that is, found in the things themselves.
Secondary Qualities: Properties we ascribe to bodies, but that are not in themselves but are merely sensations produced in us by variations in the extension. For the French philosopher, these qualities are subjective, i.e., they do not exist outside of us. Examples of them would be colors or flavors.
Baruch Spinoza
Substance: What is in itself and is conceived through itself, i.e., that whose concept does not need the concept of another thing to form. As for Spinoza, the only idea that comes to mind directly and without depending on any other is the idea of God; only God is substance.
Attributes: Properties which the intellect perceives of a substance as constituting its essence. The unique attributes of the divine substance we are capable of knowing are thought and extension.
Modes: Affections of a substance, that is, what exists in something else through which it is also conceived. The modes of extension are finite fields, and modes of thought are the finite minds.
Intuitive Science: Knowledge of the essence of things from an adequate idea of God’s attributes. The whole system of Spinoza is addressed to achieve this intuitive science that permeates the essence of things from the divine essence.