Modern Philosophy: Rationalism, Descartes, and Knowledge
Modern Philosophy
Modern philosophy: It emphasizes the completion, not manipulation, of nature by humans. It questions the origin of privileges, contrasting them with those acquired through hard work, and promotes an equal society. It moves away from anthropocentrism, as religion loses influence, and knowledge becomes the main focus, particularly its apprehension.
1. Rationalism
1.Racionalisme: Absolute trust in human reason. Source of knowledge: Innate ideas are the only source of valid knowledge; senses provide confusing information. Scientific knowledge is rational, and therefore true. Ideal knowledge: Deductive method/mathematics (a model for rational reconstruction of knowledge). Science: Truths can be deduced from innate ideas. Knowledge and experience are separate. The core of the theory of knowledge is ideas (familiar objects, but not the idea of those objects). Substance is a basic issue.
Descartes
Descartes is the initiator of rationalism. He advocates for free and independent reason against the faith of medieval theology (Scholasticism, where reason analyzed truths accepted by God or Aristotle). Reason alone must discover the truth before accepting it. He creates a new system with deductive metaphysical foundations. He proposes dualism (body/extension, soul/mind) and mechanicism: phenomena are movements in extension, including God.
Objective
Objective: To address the problem of certainty and remake the system of knowledge to obtain only truths or certainties. Method: Cartesian methodical doubt. He is not a skeptic: Cogito ergo sum (I think, therefore I am) is the primary truth. The unitary nature of knowledge: metaphysics (roots), natural philosophy (trunk), and particular sciences (branches).
Universal method of knowledge: reason (spirit) to increase knowledge. The unitary character of knowledge is based on the unitary character of reason. The method, to discover reasons, is inspired by mathematics and logic. The perceptual method has 4 steps: 1-evidence, clarity, and distinction (true knowledge); 2-analysis to reach simple truths (decompose complex); 3-synthesis (deduce new facts from simple truths); 4-checking the analysis (enumeration) and synthesis (review).
Methodical Doubt
methodical Doubt: A preliminary step to achieve certainty (evidence). It involves critically viewing previously accepted ideas as a means to reconstruct the system of knowledge. Reasons to doubt: false testimony of the senses, the problem of clearly distinguishing dreams from reality, and the evil genius hypothesis (a being that could fool us).
First truth (certainty) and nature of the self: Cogito ergo sum; the existence of the self (finite substance) and the nature of the self as a thinking thing.
Metaphysical construct of 3 realities: I, God, and the world. God exists and is a source of truth (infinite substance), who conceived the idea of God in our mind (and is the existence of this being). This is an innate idea. If God allowed us to be deceived, he would be an evil genius.
Physics: Reality is composed of infinite substance (God) and finite substance (the world: material substance/extension (primary qualities: dimension, movement – knowledge) and spiritual/thought (secondary qualities: color, flavor – senses): metaphysical dualism). Variations in nature (extension changes), physical phenomena (movements): mechanicism (the world is a machine, and God is the first author of constant movement).
Anthropology: The human being is composed of a thinking substance/spirit and an extensive substance/body. The divine link unites the soul to the brain, influencing the body (dualism: the immortal soul can exist without the body). The soul does not need our body’s mechanisms; animals are pure mechanisms without a soul. The soul is born free.