Hi Jim. The probability of sentience would be relevant if the welfare range dropped very fast as the probability of sentience decreases. For example, if "welfare range" = "probabilty"^"exponent", and "exponent" is very high. For instance, an exponent of 5 would lead to a 10 % chance of sentience resulting in a welfare range of 10^-5, and therefore in a sentience-adjusted welfare range of 10^-6. However, it is unclear to me why the probability of sentience and welfare would related in that way. So the point of your post remains.

Hi Michael. Thanks for sharing.

It was Graziano's papers (2021, 2022, some clarifications in 2020) that made illusionism click for me

I found the article from 2022 clarifying (I have not looked into the other 2), but I am still endorsing (physical) realism. I have found persuasive Hakwan Lau's views about consciousness. So I asked Gemini "What would Lau say about strong illusionism?". The answer is below. It makes a lot of sense to me. I would be curious to know your thoughts. I wonder whether disagreements between illusionists and realists are largely semantic.

Hakwan Lau is fundamentally opposed to strong illusionism. While he agrees with illusionists that our introspection is imperfect and fails to reveal the physical mechanics of our brains, he completely rejects their conclusion that this makes phenomenal consciousness a "false belief" or a non-existent property.

In his book In Consciousness We Trust, Lau argues that strong illusionism throws the baby out with the bathwater. Here is how he dismantles the strong illusionist position:

1. Macro-Level Summaries are Not "Illusions"

Strong illusionists (like Graziano, Dennett, and Frankish) argue that because our internal models don't represent the micro-physical details of our neural wiring, the non-physical "magic" they report must be a hallucination.

Lau counters this with a functional analogy: macroscopic metrics are real, even if they ignore microscopic details. When a digital thermometer gives you a reading of 20°C, it is not giving you a detailed map of the kinetic energy of billions of individual air molecules. It is giving you a simplified, macroscopic summary. But that doesn't mean "temperature" is an illusion or a false belief.

Similarly, Lau's Perceptual Reality Monitoring (PRM) argues that the prefrontal cortex generates a macroscopic summary of sensory reliability. It evaluates a signal and outputs a tag: This is real and present. Just because that tag lacks the metadata of neurotransmitter release doesn't make the resulting subjective experience an illusion. It is a highly accurate, biologically real computational output.

2. The Fallacy of the "Perfect" Introspection

Illusionism relies on the premise that for consciousness to be real, it must perfectly match our intuitive, pre-scientific introspective beliefs about it (i.e., that it is magical, ethereal, or non-physical). Because science proves it isn't magical, illusionists conclude it isn't real.

Lau points out that this is an unfair standard. Science routinely redefines phenomena without eliminating them. When we discovered that water is H₂O rather than an indivisible classical element, we didn't declare that water was an illusion. Lau argues we should treat consciousness the same way: it isn't the magical inner theater we intuitively thought it was, but rather a physical, metacognitive reality-monitoring system. Redefining it doesn't erase its existence.

3. The Evolutionary Reality of "Presence"

Strong illusionists argue that the "feeling" of experience is just an evolutionary trick to force an organism to care about its environment.

Lau argues that the brain has a much more specific, computationally vital need for this feeling: it must distinguish reality from its own internal noise. A brain constantly generates internal imagery—dreams, memories, imagination, and predictive models. If an organism cannot tell the difference between a memory of a predator and a real predator right in front of it, it will not survive.

For Lau, subjective consciousness is that mechanism. When the PRM system successfully tags a sensory signal as originating from the external world, it generates a feeling of undeniable "presence." That presence is not a trick; it is the correct computational answer to the problem of reality monitoring.

Summary

Lau would say that strong illusionists correctly identify that the brain uses simplified representations, but they make a fatal philosophical error in concluding that simplified representations are false. To Lau, subjective experience is the brain's very real, very physical mechanism for anchoring us in reality.

Hi Cynthia. Thanks for the great context.

I wonder how much the results of the CSES study would change if the management practices were similarly good for both conditions (instead of worse for the cage-free chickens). You replied to my related question below that "My [your] general sense is that option A leads to a greater welfare increase".

Relatedly, I [Vasco] wonder how much welfare varies within production systems. For example, I am interested in knowing which of the following results in a greater increase in welfare. Layers going from:

• A. Median furnished cages in the European Union (EU) to median cage-free aviaries in the EU. By median furnished cages in the EU, I mean ones with higher welfare per chicken-year than 50 % of the furnished cages in the EU.
• B. 10th percentile furnished cages in the EU to 90th percentile furnished cages in the EU.

Do you have sense of how these compare?

~30% preference studies showing that hens really value the things they can only access in cage-free (nesting boxes, perches, dustbathing, etc)

The above is an argument against barren battery cages, but not against all types of cages? All caged chickens in the European Union (EU) must have “a nest”, “litter such that pecking and scratching are possible”, and “appropriate perches of at least 15 cm”. Relatedly, I estimate moving hens from battery to furnished cages increases the welfare of chickens 70.6 % as much as moving hens from battery cages to cage-free aviaries.

Hi Abhi. Thanks for sharing.

Are you considering the risk of research on alternative proteins decreasing the welfare of farmed animals by decreasing the population of farmed animals with positive lives? I estimated cage-free layers and slower growth broilers have negative, but close to neutral lives. I am reasonably confident that caged layers and fast growth broilers have negative lives, but very uncertain about other cases. Here is an example of why this may matter in the context of eggs. 64.3 % (= 1 - 0.357) of layers in the European Union (EU) were outside cages in 2025. Funding work on alternative proteins does not have an immediate effect. It could be that it mostly reduces the consumption of eggs in 10 years, when the fraction of cage-free layers will likely be higher, and mortality lower due to improvements from experience. So I can see research on plant-based alternatives to eggs leading to fewer layers in the EU with positive lives.

Hi Matthew. Great post. I really like combinations of numbers and story-telling. I think they are a core motivation for people getting involved in effective giving.

Hi Huw. Thanks for sharing.

A vast and rapid injection of surplus labour into the global economy is potentially very bad

It is worth noting the speed and scope of an injection of surplus labour is not independent from how it impacts people. I am sceptical of a vast and rapid injection. However, if it happens, I would still expect it to be good.

I remain open to bets against short timelines for transformative AI (TAI), or what they supposedly imply, up to 10 k$.

Thanks for sharing your thoughts.

Thanks for your suggestion on how to present CEAs, we'll think about this further.

Great.

• I think that existing disagregated (non scaled) metrics already allow us to make reasonable guesses for what is cost effective to help animals.

A greater spread of pain intensities would update me (at the margin) towards prioritising very painful welfare issues happening over a short time (in particular, just before slaughter) over less painful ones affecting the whole life of animals

I also wonder whether there are cases where the time in less intense pain is decreased cost-effectively, but the time in more intense pain is increased. In such cases, one would have to rely on views about pain intensities to determine whether there is a reduction in pain. The Welfare Footprint Institute (WFI) estimates that cage-free layers experience less annoying and hurtful pain than ones in furnished cages, but that it is unclear whether they experience more or less disabling and excruciating pain. "The analysis primarily aimed to estimate the minimum welfare improvement associated with transitioning to cage-free housing". So it could be that cage-free layers also experience less disabling and excruciating pain. However, if this remains unclear accounting for all welfare issues as accurately as possible, and one believes disabling and excruciating pain are much more intense than annoying and hurtful pain, it could be unclear whether cage-free egg campaigns decrease or increase pain.

• I am not confident that we will ever gain lots of clarity on scaling, as there are lots of known unknowns and reasonable disagreements on questions up and downstream from how to scale things (sentience, range, etc.)

I am also not confident. However, I think there is high value of information in making at least one good attempt to quantify the intensity of excruciating pain.

Given the subjective nature of pain, I am not convinced a survey sampling from such a specific group is particularly externally valid (I also don't know that any survey of humans will ever be externally valid to how we'd scale pain across other animals).

I agree comparisons across different pain intensities and species will remain very uncertain.

I replied to the last link here

I replied there.

I think we should aim to have secondary effects of interventions

Great to know. Do you have any concrete plans or timelines? If not, how much funding would you need?

Nitpick. I would not call effects on non-target individuals "secondary". I think they may be much larger than those on the target individuals (in expectation), and "secundary" makes it sound like they are less important to consider.

I want to do it in a way that doesn't unnecessarily penalize/reward areas where that data is/is not available

Makes sense.

and to not have the effects of all interventions be dominated by deeply uncertain secondary impacts

What if, given reasonable moral and empirical views, we should in fact be very uncertain about whether practically any intervention is better or worse than nothing accounting for effects on non-target individuals? I think this would be useful to know. The model should not force the conclusion that interventions which have historically been supported by the effective altruism community (like saving human lives, and cage-free egg campaigns) are better than nothing for all reasonable moral and empirical views?