• Moral truths = God-independent transcendent truths.
Maths analogy. Platonism. Moral elitism. Acrasia.
• Moral truths = natural facts. The open question argument
and the naturalistic fallacy.
• Moral truths = relational properties which provide
reasons for action. Analogy with secondary properties.
• Issues: How is knowledge of moral truth possible? How
is agreement over moral truth possible? To what extent
can such truths motivate/justify action?
• a metaethical view, a form of moral realism, and
so in turn a form of cognitivism.
• The ethical naturalist holds: that ethical
sentences express propositions, some such
propositions are true and those propositions are
made true by objective features of the world.
• Hence moral features of the world can be
reduced to some set of non-moral features.
Ethical Naturalism: the details
• moral facts are identical with (or reducible
to) natural facts, especially psychological
• what is morally desirable = what is in fact
• moral propositions simply report or
describe how things are in the world.
• So moral truths are real, but they aren’t
• “…asks no more of the world than we
already know is there—the ordinary
features of things on the basis of which we
make decisions about them, like or dislike
them, fear them and avoid them, desire
them and seek them out. It asks no more
than this: a natural world, and patterns of
reaction to it.”
– Simon Blackburn
Ethics: science, not mystery
• ‘parsimonious naturalistic metaphysics’: no
nonnatural or supernatural facts.
• objective moral facts and properties are facts
about the natural world.
• so ethics is an empirical science dealing with
moral facts about the normative and evaluative
dimension of events, character, judgement and
• This category of facts is not mysterious, special,
transcendent, or sui generis, but within the
scope of the natural and social sciences.
Ethical Naturalism at work
• So, for instance, in explaining why torture is
wrong my moral judgement describes a
naturalistic state of affairs.
– Everyone agrees that eating people is wrong – this is
just a natural fact about human beings.
• For the same reason, incest is not right –
– the play ‘Oedipus’, although written in ancient Greece,
speaks to us all
– …because it details a moral fact that is an actual fact.
• Realism without mystery:
– makes robust sense of moral objectivity and moral knowledge,
allows moral utterances to be truth-apt and for some of them to
– the domain of moral value is part of the familiar natural world,
known about in broadly empirical ways.
– Fact/value distinction is rejected
• preferable to rival forms of moral realism, such as
Platonic Realism (Mackie: “queer”): no metaphysically
far out entities or properties without a plausible epistemic
story of how we can obtain knowledge of them.
• ‘Best available explanation’ - J. J. C. Smart's view –
– science is best guide to metaphysical truth but not infallible.
– As a work in progress, still far more to be trusted than theology,
Brief Writing Task
• Explain Moral Naturalism and illustrate at
least one strength of the view.
– You may wish to contrast it with moral
• Outline and illustrate one weakness of
• Is morality amenable to observational testing, just as
scientific principles are?
• Moore’s Naturalistic Fallacy: can natural properties be
– The ‘simple’, non-natural property of goodness cannot be
reduced to some natural quality or other – ‘Is it true that ‘good’
means X? (The ‘Open Question’ argument)
– What is pleasurable, what is desirable, and what are proper
functions of a person might not be what is good for that person,
– but even if they were, they are not the same as, or the definition
of, what is good.
• EN wrong or vague as
– 1) much present science will turn out false;
– 2) our present grasp of what an ideal science might say about
morals is vague;
– 3) what ‘nature’ means or ‘natural law’ means is vague;
• Do ‘water’ and ‘H20’ refer to the same set of
• Do ‘temperature’ and ‘mean molecular kinetic
energy’ refer to the same set of natural
• Do these equivalent terms have the same
• What bearing does this finding have on Moore’s
Naturalistic Fallacy and the Open Question
The ‘Open Question’ Argument
• Moore’s argument that the good is
indefinable is known as ‘The Open
• O.Q. Arg. = asking "Is it true
that X means/is Y?"
– Closed question if the answer is ‘Yes’ or ‘No’
• Shows that X is clearly defined
– Open question if a conceptually competent
person can debate the response.
• Shows that X is not clearly defined
Moore: All moral questions = Open
• Their answers cannot be deduced from the concepts in
the terms alone.
– For Moore, all moral questions are synthetic, not analytic.
• The Open Question Argument shows any attempt to
identify morality with some set of observable, natural
properties will always be an open question.
– Contrast e.g. colour identities, which are observable and
public…we know what ‘yellow’ is, or means
– So moral facts cannot be reduced to natural properties
• Hence Ethical Naturalism (= moral values are found in
nature) is therefore false.
• Instead, ethical values are intuited.
• …[but appeals to self-evidence are problematic…]
Response to OQ Argument
• OQA attacks claim that moral facts/properties can be
identified with non-moral, natural facts (metaphysical thesis)
• But does OQA only establish that moral /non-moral terms
aren’t synonyms (semantic thesis)?
– Example: I can ask if ‘vixen’ means ‘female fox’ and investigate
– Once I learn that ‘vixen’ and ‘female fox’ refer to the same entity,
then I cannot but know this.
– Similarly, ‘good’ might not be synonymous with ‘virtue’ – but they
might refer to the same property.
– ‘H20’ and ‘water’ pick out the same properties.
– So do ‘temperature’ and ‘mean molecular kinetic energy’
• Could ‘goodness’ have a different meaning to e.g. ‘pleasure’
but still refer to the same set of properties?
• Link (to general argument)
Write a PEARL structure about Moore’s
• How would the following be recuperable
as moral naturalists?
– Hume (later on)
Forms of Ethical Naturalism
• The Aristotelian view of the ‘good life’ as being to do with the
flourishing or realisation of the natural capacities of human beings
means that ethical values are reducible to natural properties. (See
also the Stoic notion of "activities which are consequential upon a
• Nietzsche’s view of the importance of the Will to Power as the
mechanism which explains why things are as they are.
• Nihilism: it is a natural fact that there are no moral truths. Morality is
merely a superstitious remnant of religion.
• Modern evolutionary psychology: Ethical values are natural
properties studied by e.g. the social sciences rather than the
physical sciences. Remember Marc Hauser’s Trolley Problems we
did last year?
• Utilitarianism/Consequentialism: pleasure is good, and whether
something is pleasurable or not is a natural fact.
• Some forms of emotivism: the ‘Common principle of the human
frame’ is the same for all of us.
• Read ahead in handout about:
– Moral truths = relational properties which
provide reasons for action. Analogy with
• Revise as seems best to you:
– Philosophy of Mind
– Normative Ethics: Kant, Mill, Aristotle, Mill,
– Metaethics: Emotivism, Cultural Relativism,
Moral Realism (Plato), Moral Realism (Ethical
• And: consider – what practical ethical
problem would you choose to consider?
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