Harman, Gilbert. The Status of Morality. Oxford: Oxford University Press, 1977, 3-10.
Harman argues that ethical theories do not – and cannot – have any observational evidence in their favor, as opposed to scientiﬁc and mathematical theories. This is because moral facts play no role in explaining why we make certain sorts of observations, unlike scientiﬁc facts. Harman means to use this as evidence that moral facts are not real (this is not explicit in this article, but is clear given his wider body of work).
Harman gives the example of a scientist who sees a vapor trail in a cloud chamber and thinks that this is the result of a proton. In order to explain the observation, we need to assume certain things about the situation; namely:(i) the scientist is in a certain psychological set (e.g., he believes a very speciﬁc physical theory is true, he believes his experimental apparatus works correctly); and (ii) a proton really did ﬂit across the chamber, causing the vapor trail. We need (ii) because the addition of this further assumption about physical facts best explains why the scientist saw the vapor trail in the ﬁrst place. This observation will then serve as evidence for the physical
theory the scientist holds, to the extent that the physical theory best explains the presence of the proton.
Harman thinks that in the case of moral theories, moral principles play no role in explaining observations. So, when a person sees an act and says, “That is wrong,” a moral principle can explain the wrongness of the act, if
indeed the act is wrong according to that principle, but it cannot explain why the person made the observation that she did. Rather, all we need do in the case of a moral observation is assume a certain psychological set on the part of the observer.
In the case of the vapor trail, the observation serves as evidence for a given physical theory, which explains the proton, which itself explains the vapor trail, which itself explains the observation. But in the case of any moral observation, the observation merely evinces a certain psychological set on the part of the observer, which itself explains the observation. Any rightness or wrongness embodied by an act does not explain a moral observation, and thus cannot serve as evidence for moral theories which explain the rightness
or wrongness of the act.
Harman then disputes the notion that moral facts might exist but might be inaccessible to observation, just like mathematical facts. Harman thinks that any analogy between moral facts and mathematical facts fails because
there is indirect evidence for mathematical facts, unlike moral facts. This is because mathematical facts undergird much of scientiﬁc explanation. There is no comparable role for moral facts in explaining moral theories; therefore, there is no observational evidence for moral facts whatsoever, direct or indirect.
Argument One (We ought to assume moral facts aren’t real)
- If a posited fact cannot have any observational evidence (direct or indirect) in its favor, then we ought to assume that it does not exist.*
- Moral facts cannot have any observational evidence (direct or indirect) in their favor.
S1. In order to have direct observational evidence in its favor, a fact
needs to evince a theory, which itself explains speciﬁc observations.*
S2. Moral facts cannot explain why speciﬁc moral observations
occur (only observer psychology can).
S3. Therefore, moral facts cannot have direct observational evidence in their favor. (S1,S2)
S4. Moral facts can have no indirect observational evidence.
S5. Therefore, moral facts cannot have any observational evidence (direct or indirect) in their favor. (S3,S4)
3. Therefore, we ought to assume moral facts do not exist. (1,2)
1. (∀x)[(Px ∧ ¬Ox) → ¬Rx]
2. Pm ∧ ¬Om … Therefore, ¬Rx
3. (Pm ∧ ¬Om) → ¬Rm (1, UI)
4. ¬Rm (3, 2,MP)
Where Px=x is posited as real, Ox=There can be observational evidence
for x, Rx=x is real, and m=Moral facts.