Hume's Enquiry, section XII

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Hume, Section XII, parts 1 and 2

• Hume distinguishes two kinds of skepticism
  1. Antecedent skepticism: we adopt universal doubt to discover the indubitable.
  2. Academic skepticism: we derive a skepticism.
• Hume considers an academic skepticism about the existence of external objects. How can we know they exist and cause our senses of them?
  • This is a matter of fact, so we must have some experience to know.
  • But we only experience certain impressions, such as a shape and color. We never experience the table directly or as a whole.
  • Consider also the status of the table when we don't perceive it.
  • Senses cannot then justify our belief in objects.
• What about deriving objects from posits about a supreme being? But skepticism can extend to arguments for the existence of God.
• Worse, we may come to believe that all sensible qualities of objects are "in us" in some sense.
• Continuum of space and time, in geometrical and abstract reasoning, appear absurd and lead us naturally to doubts about the power and consistency of reason.
• Two kinds of objections to "moral evidence" (matters of fact)
  1. Popular: recognition of our many mistakes leading to an impractical skepticism which no one really obeys outside of the classroom.
  2. Philosophical: reasoning about, for example, cause and effect can lead us to have correct doubts.
• Hume however attacks strong skepticism ("pyrrhonism") on practical grounds: what does the radical skeptic hope to accomplish? The position is impractical.

Hume, Section XII, part 3

• Academic skepticism can lead to a healthy skepticism that is useful. It can:
  • lead us to overcome dogmatism.
  • convince us to focus on problems we can best solve.
• Hume again reminds us that all knowledge is either relations of ideas of matters of fact.
• Relations of ideas is only math.
• Matters of fact can only be based upon experience.
• Theological reasoning must be based in part on faith.
• Ethical reasoning is also reasoning about matters of fact and an expression of sentiments.
• Hume has a stunning close, which was the most radical statement of empiricism made:

  "When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of act and existence? No. Commit it then to the flames: For it can contain nothing but sophistry and illusion."