Historical Themes

  • Central Role of Arguments
    • Philosophy is the investigation by rational argument of fundamental issues.
    • Philosophers investigate the issues by framing hypotheses and formulating and evaluating arguments pro and con.
    • An argument is a piece of reasoning, from premises to a conclusion.
  • Arguments improve over the centuries
    • Hume’s arguments, for example, are much better than Descartes’.
  • Rationalism vs Empiricism
    • Rationalism is the view that
      • Important truths about the world can be established by a priori reasoning, i.e. by logical deduction from self-evident truths.
        • A priori means independent of experience.
    • Empiricism is the view that
      • Important truths about the world can only be established by a posteriori reasoning.
  • Approach to Doing Philosophy
    • Some philosophers put forth fundamental theories of everything.
      • Descartes, Spinoza, Kant
    • Others address philosophic issues one at a time.
      • G.E. Moore
  • Ontology
    • The ontology (or ontological commitment) of a theory consists of the kinds of entities it postulates.  For example,
      • Idealism: only minds and mental phenomena
        • Berkeley, Bradley
      • Materialism: only physical objects and processes
        • Thomas Hobbes
      • Monism: only one kind of substance
        • Spinoza
      • Dualism: two kinds of substance, mental and physical.
        • Descartes
  • Extreme Metaphysics vs Common Sense
    • Extreme Metaphysics
      • Some philosophers have argued that there are no physical objects, that time is unreal, and that tomatoes aren’t red or any other color.
    • Worldview of Common Sense and Science
      • The universe consists of physical objects, atoms, subatomic particles, radiation, energy, space, and time.
      • Perception and memory are reliable though fallible.
      • Events are generally caused.
      • The universe runs according to laws of nature.
      • Human beings and some animal species are conscious.
  • Skepticism vs Common Sense
    • Skepticism
      • Skepticism in philosophy is the view that there’s no rational basis for believing much of what is taken to be obvious, for example:
        • that there are physical objects existing in space and time
        • that other human beings are conscious
        • that there will be a sunrise tomorrow.
    • Common Sense Worldview
      • It’s rational to believe the worldview of common sense and science. Everyone knows that there are physical objects, that other human beings are conscious, and that there will be a sunrise tomorrow.
  • Role of Math and Science
    • Developments in math and science have affected philosophy significantly
      • Mathematical Proof
        • Proof in Euclid’s Elements that √2 is irrational
      • Axiom Systems
        • Euclid’s axiom system of plane geometry
      • Scientific Theories
        • Newton’s laws of motion and his theory of gravitation