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PHIL414 Themes From Hume

This paper deals with three themes from David Hume and discusses their consequences for contemporary meta-ethics: The Slavery of Reason Thesis; The Motivation Argument; Hume’s No-Ought-From-Is thesis.

This is a paper straddling metaethics (the nature and justification of moral judgements), the history of philosophy and the philosophy of logic. It deals with three themes from the work of David Hume (1711-1776) together with 'matters arising' from the Humean agenda:

  • The Slavery of Reason Thesis ('reason is and ought only to be the slave of the passions'). What does this mean? Is the Slavery of Reason Thesis (or something like it) correct? And what (if anything) does this suggest about the nature of ethics?
  • The Motivation (or Influence) Argument:
    1. Morals have an influence on the actions and affections. [Premise]
    2. Reason alone, as we have already proved, can never have any such influence. [Premise]
    3. Morals...cannot be derived from reason
    What exactly is this argument supposed to prove? Does it succeed? If not, is there a decent argument in the neighbourhood that proves something similar? Can it be used to support non-cognitivism, the idea that moral judgements are neither true nor false
  • Hume's No-Ought-From-Is thesis: '[It] seems altogether inconceivable', says David Hume, 'that this new relation or affirmation [ought] can be a deduction from others, which are entirely different from it'. What did Hume mean by this? Can you deduce an ought from an is? If not, why not? And what (if anything) does this suggest about the status of moral judgements? We focus on the idea, common in the 18th century, that logic is conservative - that in a valid inference you cannot get out what you haven't put in. In a famous paper the great New Zealand logician Arthur Prior challenged No-Ought-From-Is, along with the concept of conservativeness. We discuss the responses of Pigden, Schurz, Greg Restall and Gillian Russell, who all try to vindicate different versions of No-Ought-From-Is in the face of Prior's counterexamples

Paper title Themes From Hume
Paper code PHIL414
Subject Philosophy
EFTS 0.1667
Points 20 points
Teaching period Second Semester
Domestic Tuition Fees (NZD) $1,120.06
International Tuition Fees (NZD) $4,439.89

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36 PHIL points at 200-level or above
PHIL 314
May not be credited together with PHIL 458 passed before 2011.
  • Coursebook: Is, Ought and All That - Themes From Hume (available form uniprint and as pdf from Blackboard)
  • Pigden, Charles ed (2009) Hume on Motivation and Virtue, Houndmills, Basingstoke: Palgrave-Macmillan.*
  • Pigden, Charles ed (2010) Hume on Motivation and Virtue, Houndmills, Basingstoke: Palgrave-Macmillan.*
  • Hume, David (2006) Moral Philosophy, (Sayre-McCord ed), Indianapolis: Hackett.**
  • Hume, David (2007) An Enquiry Concerning Human Understanding, P. Millican ed. Oxford, Oxford University Press**
*Note: Copies on reserve in the Library. Draft versions of many of the constituent papers available online.
**Note: These are useful editions for the purposes of this paper, but good searchable e-texts of Hume's works are widely available online.
Graduate Attributes Emphasised
Interdisciplinary perspective, Scholarship, Communication, Critical thinking, Ethics, Self-motivation.
View more information about Otago's graduate attributes.
Learning Outcomes
Students who successfully complete the paper will acquire
  • A critical understanding of the ideas, theses and themes discussed in this paper
  • Enhanced knowledge of Hume and his relevance to contemporary ethics and moral psychology, plus an enhanced understanding of both formal logic and logical theory
  • Enhanced logical, analytical, communicative and writing skills
This is a 400-level paper aimed primarily at honours students in Philosophy or Philosophy, Politics and Economics, especially those who have done some logic (PHIL 105 or PHIL 222) and have an interest in ethics and the history of philosophy.

Teaching staff

Professor Michael LeBuffe

Paper Structure
Two 2-hour lecture/seminars per week, two essays and a final exam

Topics covered include:
  • How do the Slavery of Reason Thesis, the Motivation Argument and No-Ought-From-Is fit together in the argument of Treatise 3.1.1?
  • 'Reason is and ought only to be the slave of the passions'. What does this mean and is it true?
  • The Slavery of Reason Thesis and rationalism
  • The Slavery of Reason Thesis and the error theory
  • The Slavery of Reason Thesis and contemporary metaethics
  • Norms of rationality
  • No-Ought-From-Is (NOFI): logical and semantic autonomy*
  • No-Ought-From-Is: its role in Hume's overall argument
  • Hume's NOFI and the concept of deduction in the 18th century*
  • NOFI in the 20th century - what's it got to do with non-cognitivism?
  • NOFI, Prior's paradox and Shorter's critique*
  • Moral belief and internalism
  • Does the Motivation Argument succeed as an argument for non-cognitivism?*
  • 'Hume's Master Argument' and NOFI
  • Hume seems to think that it is sometimes okay to go with the flow of our non-rational propensities and sometimes not: Why?
  • In-Class Presentations: Three in-class presentations, each worth 10% of the final grade. Presentations to take about 10 minutes' reading time
  • Internal Assessment: Students will write two essays during the paper. They can choose from a list of topics prepared by the lecturer.
    • First essay (3,000 words maximum) 30%
    • Second essay (5,000 words maximum) 40%
Note: One essay and at least one of the presentations must be on one of the starred (*) more logical topics.
Teaching Arrangements
Two 2-hour lectures/seminars per week, with a short coffee break halfway through.

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Second Semester

Teaching method
This paper is taught On Campus
Learning management system


Stream Days Times Weeks
A1 Monday 16:00-17:50 28-34, 36-41
Thursday 13:00-14:50 28-34, 36-41