Summary
- This analysis estimates the expected moral weight of the beings of various species relative to humans for various types of moral weight distributions.
- The mean moral weight is close to 1 for all the considered species, ranging from 0.5 to 5 excluding the lognormal and pareto distributions (for which it is even higher, but seemingly inaccurate).
I welcome comments about how to interpret the results.
Methodology
The expected moral weight of the beings of various species relative to humans was determined from the product between:
- The probability of the beings of the species having moral patienthood, as defined by Luke Muehlhauser here, which was set to the values provided in this section of Open Philanthropy's 2017 Report on Consciousness and Moral Patienthood.
- The mean of a distribution whose 10th and 90th percentiles were set to the lower and upper bounds of the "80 % prediction interval" guessed by Luke Muehlhauser here for the moral weight of various species relative to humans conditional on the respective beings having moral patienthood (see "Moral weights of various species").
- The mean of the distribution was computed from the quantiles as described here.
The expected moral weight might depend on the theory of consciousness. The above product is implicitly assumed to represent the expected weighted mean of the moral weight distributions of the various theories of consciousness. These are, in turn, supposed to produce (summable) moral weight distributions. Potential concerns about calculating expected moral weights are discussed here.
Results
The mean and median moral weight of various species relative to humans for uniform, normal, loguniform, lognormal, pareto and logistic distributions were calculated here, and are presented in the tables below[1].
Species | Mean moral weight relative to humans | |||||
---|---|---|---|---|---|---|
Uniform | Normal | Loguniform | Lognormal | Pareto | Logistic | |
Chimpanzees | 0.900 | 0.900 | 0.490 | 3.27 | 0.900 | |
Pigs | 1.40 | 1.40 | 0.765 | 13.1 | 1.40 | |
Cows | 2.00 | 2.00 | 1.14 | 132 | 2.00 | |
Chickens | 4.00 | 4.00 | 2.41 | 1.50 k | 4.00 | |
Rainbow trouts | 4.55 | 4.55 | 3.00 | 28.4 k | 4.55 | |
Fruit flies | 2.50 | 2.50 | 1.95 | 2.46 M | 2.50 |
Species | Median moral weight relative to humans | |||||
---|---|---|---|---|---|---|
Uniform | Normal | Loguniform | Lognormal | Pareto[2] | Logistic | |
Chimpanzees | 0.900 | 0.900 | 0.0402 | 0.0402 | 0.00111 | 0.900 |
Pigs | 1.40 | 1.40 | 0.0335 | 0.0335 | 495 | 1.40 |
Cows | 2.00 | 2.00 | 0.0179 | 0.0179 | 99.1 | 2.00 |
Chickens | 4.00 | 4.00 | 0.0179 | 0.0179 | 49.5 | 4.00 |
Rainbow trouts | 4.55 | 4.55 | 0.00798 | 0.00798 | 8.67 | 4.55 |
Fruit flies | 2.50 | 2.50 | 0.00192 | 0.00192 | 0.310 | 2.50 |
Discussion
The results suggest animals and humans have a similar moral value. The mean moral weight is close to 1 for all the considered species, ranging from 0.5 to 5 excluding the lognormal and pareto distributions.
The lognormal distributions do not seem to represent the moral weights accurately. Their heavy right tails imply high mean moral weights, which would arguably require frequent strong experiences. However, as noted here by Jason Schukraft, "it appears unlikely that evolution would select for animals with a non-contiguous range that was exclusively extraordinarily strong because extremely intense experiences are distracting in a way that appears likely to reduce fitness".
The pareto distributions are not reasonable representions of the moral weights, as they lead to mean moral weights of infinity.
Loguniform distributions appear to be the best choice amongst the 6 studied types of distributions:
- Being positive, they prohibit negative moral weights.
- Having mean larger than the median, they are compatible with the intuition that the moral weight is a product (not a sum) of multiple dimensions (for example, clock speed of consciousness, unity of consciousness, and unity-independent intensity of valenced aspects of consciousness).
- Being bounded, they prevent unreasonably large mean moral weights.
- ^
The probability of pigs being moral patients is not provided in this section of Open Philanthropy's 2017 Report on Consciousness and Moral Patienthood. However, it was assumed to be equal to that of cows and chickens (80 %).
- ^
1 equals .
To pick a bit on the notion from this article which establishes the range of moral weights in question.
They say fruit flies range from a moral weight of .000001 - 20 times the moral significance of human experience. In log space, that's between 10^-6 and 10^1.3. The mean log uniform distribution, as you mention, is at 1.95. I find the significant probability mass being above 1 as implausible for fruit flies, and I will go on to explain why I think except for species like dogs, pigs, elephants, octopuses, or other long living intelligent social creatures it would be difficult to argue that they are plausibly more moral weight than a human.
Arguments for fruit flies being about as likely to be more morally significant than humans as less:
A fruit fly may experience things much faster than a human, meaning their short lives may be experienced longer than how long a human may perceive their lives to be.
They may experience things more intensely as well, given their single pointed focus on conscious experience. This means although it's possible they experience suffering more fully, it may also be possible that they can completely forget and move their focus to some other task if focusing on the pain does not confer an advantage.
They may be less "distracted" than humans, in that they experience the world more fully and in full awareness.
They are also typically considered innocent of other moral wrongdoings, so perhaps that makes them more morally valuable in some moral systems.
Arguments against:
There are a whole host of reasons to think that they could not possibly be as morally significant as a human.
I think it's reasonable to say a fruit fly cannot remember things in the long term, and it cannot contemplate or ruminate, which is one of the worst aspects of negative experiences and pain. I think most people would prefer to have experiences of extreme pain and trauma erased from their lives.
A fruit fly lives a tiny fraction of the duration of a human's life, so it would have to experience its own life much faster.
A human can be considered an ensemble or family of different personalities and conscious processes. Each one of these may have moral significance, increasing the relative moral significance of a human.
The more complex something is, typically, it is more valued in generic terms.
Humans form a network of social connections and social connections. When a human is lost, their loss is understood and grieved by many other humans, thus greatly increasing the overall negative effect of harm to a human compared to a fruit fly.
Humans have very few children relative to fruit fly, so they are likely value higher on an individual level by their families and communities.
In summary the most relevant factors for moral significance are likely the degree of social embeddedness, the experience of higher order emotions and complexity in general, the ability to grieve, long lives, and long memories, which strongly implies that humans are more morally significant than all or most other animals.
A final thought is that we don't know with very high confidence that animals are conscious in the way that we care about morally, but we know this for sure with humans. For that reason, we would be safer to prefer to save humans first, in case we were wrong about animals having conscious experiences in the first place.
Thanks for clarifying!