香港中文大学 黄勇教授 大会报告
I. Introduction
David Hume claims that
there is a huge gap between
is and ought in the following
famous
passage
Treatises .
between
The
is
from
gap
his
exists
statement
and
ought statement, because for
Hume, they are two entirel y
different t ypes of statement,
and one cannot derive an
ought statement from an is
statement. Later G. E. Moore, in his Ethica Principia, coined the
equall y if not more memorable term “naturalistic fallacy,” which
is commonl y understood to mean that it is a fallacy to derive an
ought statement from an is statement.
In this paper, I shall first examine two formalistic attempts to derive
ought from is and show w hy they are not successful. Then I shall discuss
the naturalistic attempt to derive ought from is made by contemporary
Aristotelian virtue ethicists, particularl y Rosalind Hursthouse. I argue
that such an attempt proceeds in the right direction. Its proble m largel y
lies more in the is part than the ought part: since the descriptive is
statement is problematic, the normative ought statement derived from it
becomes also problematic. So in the last section of this paper, I examine
Zhu Xi’s neo-Confucian attempt to derive ought from is, which in
general structure is similar to the neo -Aristotelian one but starts with a
different is statement. I argue that this neo -Confucian one is more
promising.
II. Two Formalistic Attempts to Derive Ought from Is and Why They Fail
I’ll start with the relativel y more recent but less known attempt b y
Mark T. Nelson, who provides the following counter -argument against
the Humean thesis:
N1. “Bertie (morall y) ought to marry Madeline” is one of
Aunt Dahlia’s beliefs.
N2. All of Aunt Dahlia’s beliefs are true.
N3. Therefore, Bertie (morall y) ought to marry Madeline.
(Nelson 1995: 555)
It is obvious that the conclusion is an ought statement and the first
premise is a is statement. In appearance the second premise is also a is
statement. However, if we say that “All of Aunt Dahlia’s beliefs are true,”
Aunt Dahlia’s belief that “Bertie (morall y) ought to marry Madeline” is
also rue; yet to say that Aunt Dahlia’s belief that “Bertie (morall y) ought
to marry Madeline” is true simpl y means that “Bertie (morall y) ought to
marry Madeline,” which is nevertheless an ought statement. So what
Nelson achieves is not to derive an ought and is but derive an ought from
an ought. To respond to our objection, Nelson makes a distinction
between the specific and general interpretation of the second premise.
However, even if emotivists are persuaded, they will realize that Nelson
does not derive an ought from is, since the second premise itself is an
(at least partiall y) ought statement.
Now I want to tu rn to an earlier but much more famous attempt to derive
ought from is, the one made by John R. Searle in his classical essay,
“How to Derive ‘Ought’ from ‘Is’?” published in 1964. Searle starts with
the following counter-example:
(1) Jones uttered the wor ds “ I hereby promise to pay you, Smith, five
dollars.”
(2) Jones promised to pay Smith five dollars.
(3) Jones placed himself under (undertook) an obligation to pay Smith
five dollars.
(4) Jones is under an obligation to pay Smith five dollars.
(5) Jones ought to pay Smith five dollars. (Searle 1964: 44)
I claim that Searle fails to derive an ought from is, since his very
conclusion, despite the appearance of the word ought in it, is actuall y
still an is or descriptive statement. W hat Searle’s whole argument
amounts to is merel y this: someone who participates at the institution of
promise ought to keep the promise; it says nothing whether the
institution is good or not or whether one ought to be part of this
institution. Since perhaps we all accept t he conclusion of Searle’s
argument, its descriptive nature is not clear. However, we can construct
a similar example like this.
(1) Jones was a whole -hearted believer in Nazism;
(2) And he found Smith hiding in a Polish famil y;
(3) Smith was a Jew
(4) Jones ought to kill Smith.
Here, the conclusion follows, not because we think Jones ought to kill
the Jew, but given the fact Jones participates at the institutional
activities of Nazism, he ought to kill Smith, even though we might want
to abolish the institution as we think Jones ought not to kill Smith.
III. Hursthouse’s Ethical Naturalism: A Right Direction
In contemporary virtue ethics, particularl y the neo -Aristotelian one,
there is a new trend of ethical naturalism. In virtue ethics, the ought
statement is often expre ssed by using the word “good,” and the ought
not statement is often expressed by using the word “bad,” since
statements containing “good” and “bad” are normative in the precisel y
the same sense as statements containing “ought” and “ought not.” Thus
the statement that “John is a good person” is equivalent to the statement
that “one ought to be a person like John,” and the statement that “John
is a bad person” is equivalent to the statement that “one ought not be a
person like John.” In Hursthouse’s word, “wh at that entails is that,
although you can evaluate and choose things according to almost any
criteria you like, you must select the noun or noun phrase you use to
describe the thing you are calling good advisedl y, for it determines the
criterion of goodnes s that are appropriate” (Hursthouse 1999: 195).
“Good” is similar to “small” but different from “red” and so it is also an
attributive term. In other words, we don’t have an independent and
uniform criterion of goodness that can be applied to anything. Ins tead,
our criterion of goodness must be specific to the thing that we describe
as good. In other words, the normative conception of good must be
derived from a descriptive conception of the thing regarded as good.
First we examines our evaluation of pl ants. Here, “we evaluate two
aspects—parts and operations —in relation to two ends” (Hursthouse
1999: 198). The two ends are (1) individual survival through the
characteristic life span of such a member of such a species and (2)
continuance of the species. (Hursthouse 1999: 198). So a good plant is
one that is well fitted with respect to its parts and operations in terms of
both its individual survival and the continuance of its species. In other
words, a good plant is one whose two aspects serve its two end s well.
Hursthouse then moves to our evaluation of animals, where two
additional aspects and two additional ends are introduced. The first new
aspect (the third aspect) is acting or doing in contrast to merel y reacting
as is found in plants. The second n ew aspect (the fourth aspect) is a
certain psychology of emotions and desires. With these two new aspects,
there are not onl y more complex ways of realizing the two ends; but
there are also two new ends to be served. The first new end (the third
end) is the “characteristic freedom from pain and characteristic pleasure
or enjoyment” (Hursthouse 1999: 199), as animals seek both freedom
from pain and enjoyment of pleasure, while plants do not. The second
new end (the fourth end), particular in social animals s uch as wolves and
bees, is “the good functioning of the social group.”
In Hursthouse’s view, evaluation of human beings have no new end
but a new aspect: rationalit y. It is primarily in virtue of our actions from
reason that we are ethicall y good or bad human beings. In the person
with the virtues, these emotions will be felt on the right occasions,
towards the right people or objects, for the right reasons. It is interesting
to see that all aspects that Hursthouse thinks are ethicall y relevant, other
than rationalit y, are also present in animals. However, why do we not
make ethical evaluations of animals and regard them as either morall y
virtuous or vicious? The reason for Hursthouse is that rationalit y, the
unique aspect in human beings, is important not onl y because it is a new
aspect to be evaluated, but also because it affects all other aspects to be
evaluated in a human being.
As a matter of fact, Hursthouse claims
that full virtue involving feeling emotions is generall y impossible
without the influence of reason.
IV. Problem with Hursthouse’s Neo -Aristotelian Approach
There is an Objection to Hursthouse ’s argument. While Hursthouse ’s
ethical naturalism can indeed respond to McDowell ’ s objection on
behalf of a rational wolf, it is still a questi on whether it can respond to
Watson’ s objection on behalf of a social gangster: “ can an objective
theory reall y establish that being a gangster is incompatible with being
a good human being? ” (Watson 1997: 67).
V. Zhu Xi’s Neo -Confucian Naturalism (xing 性 ): A More Promising
Approach
As we have seen, Hurshouse’s attempt to derive ought from is is in
the right direction. Its problem largel y lies in the is part: its does not
provide an adequate description of what human nature is. In this section,
I shall argue that Zhu Xi’s neo -Confucian attempt to derive ought from
is is largel y consistent with Hursthouse’s neo -Aristotelian one. The
difference is that he provides a different is statement, i.e., a different
description of what human nature is. Following the Mencian line of
Confucianism, Zhu Xi regards human nature not merel y as something
that human beings are born with but as something characteristic of
human beings, something that distinguishes human beings from other
beings. In this sense, he still agrees w ith Aristotle. The question is what
distinguishes human beings from other beings. Philosophers in the
Western tradition have almost unanimously accepted the view that it is
rationalit y, although they may disagree on precisel y what rationalit y is.
When Zhu Xi claims that human nature is virtuous, he does not mean
that every individual human being is actuall y already virtuous. There are
people, actuall y many people, who are not virtuous, and in this sense
many people are not charac teristicall y human beings. They are defective
human beings. In this sense, while Zhu Xi disagrees with Hursthouse on
what is characteristic of human beings, he would certainl y agree with
her when she says that “characteristic” is not a statistical notion. In other
words, while it certainl y does not mean that all humans are going on in
the characteristicall y human way, it also does not necessaril y mean that
most human beings are going on in the characteristicall y human way. To
determine whether a way is char acteristic of the human species is to see
what all humans can do (not actuall y do) that makes the human species
different from other species. So, as Hursthouse states, the notion of
“characteristic” is “avowedl y normative and is clearl y going to yield
judgments to the effect that many human beings are not going on ‘in the
way characteristic of the species’ and are thereby defective human beings”
(Hursthouse 1999: 223). It is in this sense that there is no contradiction
at all between Zhu Xi’s claim that hum an nature is virtuous and the
acknowledgement that some (and actually many) human beings are not
virtuous.
Zhu
Xi
onl y
disagrees
with
Hursthouse
on
what
is
characteristic of the human species. While for Hursthouse the wa y
characteristic of human beings is rationalit y, for Zhu Xi it is tui, the
abilit y to extend the four natural qualities, the very abilit y that makes
these four natural qualities virtues in human beings. Thus, as far as the
four natural qualities are not full y extended in a human being, this human
being is more or less ethicall y defective, just as a person who does not
have the vision characteristic of the human species is more or less
physicall y defective. More importantl y, for Zhu Xi, while a person who
is physicall y defective to a certain degree may never be able to gain the
physical abilit y characteristic of human beings, a person who is ethicall y
defective, however serious it is, can always regain the ethical way
characteristic of being human, as long as the person is willing to make a
strong enough effort of tui, since the ethical way characteristic of human
beings, while not a way lived by all or even most human beings, is a way
that all human beings can have and ought to have in order to become
characteristicall y human beings. This can also explain why we do not
condemn a person for his/her physical defects as we do for his/her ethical
defects.