Dualism, Monism, and Descartes' Skepticism

  • Materialist Position
    • Believe only in things that can be weighed, measured, and pointed to, rejecting concepts like a "soul" as unprovable.
    • Having a mind is considered an outcome of physical matter being arranged in a specific way, an "outgrowth of nature, chemistry, and biology."
    • Brain states change due to external stimulation or internal physical changes (chemicals, electricity). For example, seeing a new slide changes brain states, or remembering an upcoming algebra test alters a state of calmness to one of anxiety. These are purely physical explanations.
  • The Divide Between Dualism and Materialism
    • The two philosophical camps are fundamentally distinct and cannot be synthesized.
    • A materialist would require a dualist to abandon the idea of a spirit or soul to join their club, which is an "essential characteristic" of dualism, thus ceasing to be a dualist.
    • Some dualists may accept the material part but add a spiritual component, making them "nontypical" and difficult to categorize.
  • The Mind-Body Problem: "Who Cares?"
    • This philosophical inquiry, often questioned for its practical relevance, addresses the fundamental problem of how human beings process information and integrate sensory and memory functions with the physical body.
    • While psychology, linguistics, and medical science offer insights into how visual senses and memory work, the overarching mystery remains: "how they work together with the body."
    • Is it Special or Unique?
    • Questions arise about whether the way humans process the world is a unique human trait or shared by other creatures with brains (e.g., squirrels, cats, fish).
    • We cannot definitively know if others process things the same way as us, posing challenges for understanding and treating other beings.
    • The Inverted Spectrum
    • A hypothetical example where a person sees yellow when looking at red, but consistently identifies it as "red." This illustrates that subjective experiences of color might differ even if the objective label is the same, meaning "we don't know if everybody processes things the same way."
    • Implications
    • The presence or absence of a "soul" has "huge implications" for how we treat and understand other people and impacts religious beliefs.
  • Helpful Language and Distinctions
    • Mind and Brain
    • Brain: Has extension, weight; it is the physical organ in the head.
    • Mind: The non-physical aspect; conscious experiences, thoughts, and feelings. Distinct from the brain.
    • Types and Tokens
    • Type: A larger, general category (e.g., "student at the University of Saint Thomas").
    • Token: An individual instance within that category (e.g., "each one of you" as an individual student).
    • Phenomena and Noumena (Kant's Distinction)
    • Introduced as "$50 words$" from philosopher Immanuel Kant.
    • Phenomena: Appearances that constitute our experience; they have "no extension, no weight, no height; you can't touch them." Primarily mental states.
    • Noumena: The presumed "things themselves which constitute reality and have extension." These are the objects in the world that possess physical qualities (e.g., glasses have extension, weight, color). Our mental states (phenomena) interact with these objects (noumena).
  • Dualism and Monism: Camps and Subsets
    • Philosophical positions regarding the nature of reality and the mind-body relationship.
    • Different "tokens" or belief systems exist within the larger "type" camps of dualism and monism.
    • Dualist Varieties
    • Substance Dualists: Argue that the mind is an independently existing substance alongside the body/brain (e.g., Plato, Descartes).
    • Property Dualists: Maintain that the mind consists of independent properties that emerge from the brain but cannot be reduced to it, yet the mind is not a distinct substance itself. Like a university with independent departments (financial aid, academics, library) all working together for a common goal (educating students).
    • Monist Varieties: Believe in only one kind of substance.
    • Physicalists (Radical Monism): Argue that only the brain actually exists; it is the most common form of monism in the 20th20^{th} and 21st21^{st} centuries, including behaviorism, identity theory, and functionalism.
    • Idealists: Maintain that only the mind exists, and the physical world either doesn't exist or cannot be proven.
    • Neutral Monists: Adhere to the position that there is some other unknown, neutral substance, and both matter and mind are properties of this substance. Criticized as "bad philosophy" for lacking clear definitions of this substance.
  • The Problem Revisited: How Mind Affects Matter
    • The core problem is "explaining the relationship between minds or mental processes and bodily states or processes."
    • Specifically, "how does the nonmaterial affect the material?" For example, how does a non-physical thought to move translate into physical muscle contractions? This is known as "the ghost in the machine."
    • Conscious experiences arising from "an inert lump of gray matter endowed with electrochemical properties" and a desire causing neurons to fire are fundamental puzzles.
  • René Descartes and Skepticism
    • Background: Descartes (1596−16501596-1650) was a significant mathematician, scientist, and philosopher, known for his original contributions.
    • Descartes' Goal: In his First Meditation, Descartes aims to establish absolutely certain knowledge by doubting everything that can possibly be doubted. He sets an "impossibly high" standard, more rigorous than Clifford's empiricist view.
    • The Three Challenges to Belief (Pillars): Descartes proposes thought experiments to dismantle previously held beliefs.
    1. Sense Perception Argument (Local Attack):
      • Our senses can deceive us (e.g., mirages, mishearing, misidentifying a person).
      • If our senses have ever deceived us, then all beliefs derived from sense perception must be questioned and cannot be part of the "catalog of true beliefs."
      • This eliminates approximately rac23rac{2}{3} of our foundational beliefs. However, non-empirical truths like theoretical mathematics, logic (e.g., Modus Ponens: "If PP then QQ, PP therefore QQ"), and geometry remain untouched.
    2. The Dream Argument (Global Attack):
      • We lack any infallible way to distinguish between waking and dreaming states. There's no "little red light" in our perception to indicate if we're awake or dreaming.
      • If we cannot tell if we're dreaming, then any knowledge we think we possess could be a dream and thus mistaken.
      • This is a "global attack," eliminating all remaining beliefs, including theoretical mathematics and logic, as they could also be part of a dream reality. "You know nothing."
    3. The Evil Genius Argument (Global Attack):
      • A hypothetical scenario where an all-powerful "evil genius" or demon has the ability to manipulate and alter all sensory input and even our thoughts.
      • Every perception (e.g., seeing a PowerPoint), every tactile experience, and every thought (e.g., "2+2=42 + 2 = 4") could be a complete deception orchestrated by this entity.
      • This is also a "global attack," taking out everything we could possibly know, leading to "total skepticism."
      • Examples in popular culture: This argument is famously explored in films like The Matrix, The Truman Show, and Fight Club.
    • Conclusion of Skepticism: Descartes' skeptical arguments reduce the "catalog of true beliefs" to zero. "Everything has been reduced to total skepticism." While there are no falsehoods, there is also no knowledge.
    • Types of Skepticism:
    • Global Skepticism: Attacks all knowledge and its support (e.g., consequences of the dream and evil genius arguments).
    • Local Skepticism: Attacks specific forms of knowledge in a localized manner (e.g., the sense perception argument, or distrusting science due to pharmaceutical funding).
    • Descartes' Cavalry: The Cogito
    • Descartes' solution, "Cogito,ergoCogito, ergo sum" (I think, therefore I exist), defeats all three skeptical claims.
    • Even if our senses are wrong, "it's still you" whose senses are being deceived.
    • Even if we are dreaming, "it's still you dreaming."
    • Even if an evil genius is deceiving our thoughts, "I am still thinking those thoughts" for him to manipulate them.
    • The very act of doubting or thinking necessarily confirms the existence of a self that is doubting or thinking.
    • While Descartes attempted to use this to prove God's existence, the lecture notes that "we can't make that leap" from the Cogito alone. However, it successfully establishes the existence of the self, bringing one crucial truth into the catalog of beliefs.