Rationalism and empiricism

The Early Modern Period

• General Overview:

  • In various fields like literature, music, and architecture, the term 'Modern' usually refers to the early 20th century.

  • Philosophy, however, begins its Modern period nearly 400 years earlier due to a significant 16th-century shift in understanding nature and knowledge.

  • Thinkers such as Galileo (1564–1642) represent the onset of modern research methods, contrasting with pre-Modern views on knowledge.

  • Pre-Modern era: Featured significantly different ways of thinking about nature and its knowledge.

Pre-Modern Thought Example: Paracelsus (1493–1541)

• Quote from Paracelsus:

  • "The whole world surrounds man as a circle surrounds one point. From this it follows that all things are related to this one point... Everything that astronomical theory has profoundly fathomed... can also be applied to the firmament of the body."

• Interpretation:

  • Pre-Modern thinkers like Paracelsus viewed the universe as revolving around humanity, with parallels drawn between nature and the human body.

  • Reality was seen as a symbolic work of art created with humanity in mind.

The Shift to Modern Thinking

• Copernican Revolution (Nicolaus Copernicus, 1473–1543):

  • Proposed that the Earth was not at the center of the universe, challenging the pre-Modern worldview.

  • Traditional thinkers like Francesco Sizzi rejected discoveries like Galileo's telescope, arguing against multiple celestial bodies, citing a symbolic pattern with the number seven in nature.

• Modern Knowledge:

  • Modern thinkers no longer believed nature had special significance tied to humanity.

  • Knowledge was pursued through systematic, open-minded observation of nature rather than symbolic analogies.

• Cultural Parallels:

  • Pre-Modern thinking, including correspondence theories like the Chinese five elements (wood, water, fire, earth, metal), matched the inner world (senses) with the outer world (elements), appealing to human need for meaning.

The Renaissance Conflict and Skepticism

• Philosophical Tension:

  • The clash between old (Earth-centered) and new (Sun-centered) models led to skepticism, exemplified by Montaigne, who chose not to take sides in the debate.

  • Some philosophers advocated for a new scientific perspective.

Rationalism and Empiricism: René Descartes

Descartes' Background

• Born: 1596, France

• Education: Traditional Jesuit education focused on Aristotle and medieval interpretations.

Descartes' Shift to Modern Science

• Meditations: Descartes critiques his past education, acknowledging that many beliefs were false. He decides to demolish all previous knowledge to build a stable foundation for sciences.

• Method: Systematic skepticism, doubting sensory information and everything previously accepted.

First Meditation: Doubt and the Evil Demon

• Descartes begins by doubting everything, even his own perceptions, leading to the realization of his own existence through thinking.

The Certainty of Existence

• "I think, therefore I am": The undeniable truth of one's existence as a thinking being, regardless of deception by an evil demon.

Third Meditation: Clear and Distinct Ideas

• Descartes concludes that whatever is clearly and distinctly perceived must be true.

• The Rule: "Whatever is clear and distinct is true."

• Innate Ideas: Descartes identifies that certain ideas, like the concept of perfection, must come from an innate source (God).

God's Existence and Perfection

• Descartes argues that the idea of perfection cannot come from a less-than-perfect source, so it must be innate and placed by God.

The Nature of Knowledge and Error

• Clear and Distinct Ideas: Ideas like numbers and geometrical forms are innate and trustworthy.

• Obscure Ideas: Sensory ideas like color and smell are less reliable and often confused.

Human Error

• Source of Error: Descartes posits that errors occur when humans exercise free will to accept unclear or confused ideas. These errors are not caused by God, who is perfect.

Rationalism

• Mathematics as the Tool: Descartes emphasized the use of mathematical tools to analyze nature.

• Legacy: Descartes significantly contributed to algebra and geometry (e.g., Cartesian coordinates).

Key Concepts from Descartes' Rationalism:

• Clear and Distinct Perceptions: True knowledge comes from clear and distinct ideas.

• Innate Ideas: Certain ideas are inherent in humans, such as mathematical and geometrical concepts.

• The Role of God: God’s perfection ensures that innate ideas are trustworthy.

• Human Freedom: Errors arise from human misuse of free will, accepting ideas that are not clear and distinct.The Empiricism of John Locke: Key Points

• John Locke:

  • Studied traditional philosophy at Oxford and became interested in Descartes’ philosophy after graduation.

  • Pursued a successful career in medicine and as a civil servant.

  • Spent 20 years developing his main work, Essay Concerning Human Understanding.

  • The central goal of the Essay was to define the boundaries between opinion and knowledge.

  • Locke promoted tolerance, arguing that beyond what could be known, humans could have faith or opinion, but should not claim certainty or attack others over differing opinions.

• Locke's "Historical, Plain Method":

  • Locke rejected the rationalist view of innate ideas (ideas humans supposedly have from birth).

  • Challenged the rationalist idea that certain principles are innate (e.g., "Whatsoever is, is" and "It’s impossible for the same thing to be and not to be").

  • Locke argued that ideas are not innate—children demonstrate basic knowledge (like distinguishing their mother from a stranger) long before they understand complex logical truths.

  • Locke criticized the notion that innate ideas are present but not recognized until maturity, saying it was contradictory to claim ideas are imprinted on the soul without being perceived.

• Locke's Theory of Knowledge (Empiricism):

  • Locke argued that the mind is like a "white paper" before sensory experiences begin to shape it.

  • Simple ideas come from two sources:

    1. Sensation: Direct experiences of the external world (e.g., seeing, hearing).

    2. Reflection: Awareness of the mind's own operations (e.g., thinking, remembering).

  • These simple ideas combine into complex ideas, which include abstract concepts (justice, property, government) or imaginary inventions.

  • Locke maintained that empirical knowledge (knowledge based on experience) comes from these sources, as opposed to rationalist thought that insists on innate ideas.

• Locke's View on Knowledge:

  • Knowledge is the perception of agreement or disagreement between ideas.

  • Locke defines three degrees of knowledge:

    1. Intuitive Knowledge: Immediate understanding of the agreement or disagreement of ideas (e.g., "a circle is not a triangle").

    2. Demonstrative Knowledge: Knowledge obtained through a chain of reasoning (e.g., understanding that internal angles of a triangle add to 180 degrees).

    3. Sensitive Knowledge: Knowledge based on sensory perception (e.g., knowing the existence of the clothes you're wearing based on sensory experiences).

• Sensitive Knowledge:

  • Locke argued that sensitive knowledge (knowledge of sensory experiences) differs from other types because it deals with particular, present objects.

  • This type of knowledge is rooted in reality—what we perceive directly (e.g., looking at the sun vs. imagining it).

  • Sensitive knowledge links ideas with reality, which Locke sees as distinct from other ideas formed in the mind.

  • Locke considered skepticism about sensory knowledge impractical, believing humans are "invincibly conscious" of what they sense.

• Judgement:

  • Not all human actions are based on knowledge. Many actions are guided by judgement.

  • Judgement doesn’t give certainty but allows us to hold beliefs that are probably true.

  • Locke considered judgement (e.g., believing others' testimony) as a form of reasoning different from knowledge.

• Locke vs. Descartes:

  • Descartes: Focused on mathematical and abstract ideas, emphasizing the internal consciousness of one’s mind.

    • Descartes' theory of knowledge begins with the question, "What can I know for certain?"

    • Descartes emphasized rationalism and abstract reasoning over sensory experience.

  • Locke: Focused on the importance of experience and observation, answering the question: "What do humans know?"

    • Locke’s theory of knowledge is empirical and observational, where sensory perception plays a central role in gaining knowledge.

    • Locke's more third-person approach contrasts with Descartes' first-person approach, relying on observations of others' experiences.

• Key Differences Between Locke and Descartes:

  • Descartes: Emphasized introspection and abstract reasoning, seeing knowledge as certain if it does not depend on external realities.

  • Locke: Emphasized observation and experience, grounding knowledge in sensory perception and human interaction with the world.

• Modern Terminology:

  • The philosophical debate between internalism and externalism reflects Locke’s empirical approach versus Descartes’ more abstract focus on introspection.

Conclusion:

Locke's empiricism focuses on the role of experience and observation in the formation of knowledge, challenging rationalist claims of innate ideas and stressing the importance of tolerance in matters of faith and opinion. His work laid the foundation for later theories that bridged the gap between first-person and third-person perspectives in the study of knowledge.