The user inputs a target taxon. The tool then determines, where necessary, two related but distinct scopes: one for the sentience gate and one for the affective-capacity analysis.
You may be interested in the article âEthics Without Sentience: Facing Up to the Probable Insignificance of Phenomenal Consciousnessâ by François Kammerer. Here is a summary. Relatedly, you may like this and this very short posts by Keith Frankish. I agree with Keith that phenomenal consciousness does not exist. In any case, even if it exists, I agree with François it is not significant. Phenomenal consciousness as traditionally defined is not falsifiable (or, to be precise, it is traditionally defined such that one can only know about their own consciousness at the moment). In practice, one always has to come up with empirical proxies for it, but I feel these are largely arbitrary if it is not falsifiable. So I believe it would be better to focus just on what animals can do (as in your affective-capacity analysis), and not on assessing phenomenal sentience.
Thanks, Vasco â this is a very interesting challenge, and the pieces by Kammerer and Frankish are highly relevant.
I am not sure, however, that our use of sentience depends on the traditional conception of phenomenal consciousness that you are criticizing. In the Welfare Footprint Framework, the relevant question is whether an organism can have positive or negative affective statesâstates that can make its situation better or worse for it. We try to infer those states from converging behavioural, physiological, neural, pharmacological, cognitive, evolutionary, and ecological evidence.
This is why I would hesitate to focus only on what an organism can do. Behaviour and functional capacities are important evidence, but they are not themselves welfare. A biological or artificial system may avoid damage, learn, prioritize certain outcomes, and change its behaviour without anything necessarily feeling good or bad for it. The distinction between affective and non-affective control is therefore part of the question we are trying to investigate, rather than something we can simply set aside.
I would also hesitate to describe the empirical proxies as arbitrary. They are indirect and uncertain, and their interpretation depends partly on oneâs theory of consciousness. But some proxies are clearly more informative than others. Their value can be assessed through causal and comparative evidence, experimental interventions, and whether different classes of indicators point toward the same conclusion.
That said, your comment suggests a useful improvement to the tool. We could define the sentience gate more carefully and make clearer that it is not trying to identify an ineffable property disconnected from observable biological processes.
The workflow itself would remain the same. First, we ask whether the available evidence supports the existence of any positive or negative affective states. Only then, conditional on that assessment, do we ask how intense those states could plausibly become. These are related but distinct questions: the sentience gate concerns whether there is any affective welfare subject at all, whereas the ceiling analysis concerns the upper limit of that subjectâs affective range.
Some of the same evidence may inform both stages, but the inferential targets are different. We could make this distinction clearer in the article and in the tool, while also separating the observable evidence from the further inference about affective experience at each stage.
Someone sympathetic to Frankishâs view might interpret the same evidence without appealing to phenomenal properties as traditionally conceived. But for the WFF, we still need to distinguish systems that merely process information and regulate behaviour from organisms for which conditions can plausibly feel better or worse.
Thank you for drawing our attention to this. I think it may help us clarify both the article and the tool without changing the basic sequence of the analysis, and without requiring us to settle the broader philosophical debate before making practical progress.
Here is a thought experiment that may be helpful. Imagine you had all the empirical/âphysical evidence about an animal, including all the âbehavioural, physiological, neural, pharmacological, cognitive, evolutionary, and ecological evidenceâ. There may be practical limits to how much one could know, but I am imagining a scenario where empirical/âphysical uncertainty was fully eliminated. Would you be able to say whether the animal is sentient or not under the Welfare Footprint Framework (WFF)? If the probability of sentience is just supposed to capture empirical uncertainty under WFF, it would be either 0 or 1? For it to be higher than 0, and below 1, I think it would have to capture metaphysical or definitional uncertainty. If so, would it be better for WFF to cover just empirical uncertainty?
Under WFF, affective welfare either exists or does not exist at all. However, how can one justify such a binary distinction? Each type of empirical evidence, including âbehavioural, physiological, neural, pharmacological, cognitive, evolutionary, and ecological evidenceâ, exists on a spectrum. So I find it very counterintuitive that we could map empirical evidence to affective welfare either existing (sentience) or not existing at all (lack of sentience). I believe this would require assuming the existence of a sharp surface in the evidential space separating affective welfare existing from it not existing at all (even if there is uncertainty about the surface location), which is what feels arbitrary to me.
I should first clarify whose position is being discussed: The Welfare Footprint Framework itself does not prescribe a particular theory of sentience or affective capacity. It treats positive and negative affective experiences as the core of welfare, but it remains open about the precise biological mechanisms that produce them and about how affective capacities should ultimately be compared across species. The ideas in this series of posts are therefore better understood as our provisional contribution to this problem, developed largely for the practical purpose of making interspecific Welfare Footprint comparisons possible. They should not be presented as an official WFF position on whether sentience is categorical or graded.
My own personal view is that the biological capacities associated with sentience can vary continuously, while the minimal presence of affective experience is categorical. Nociception, memory, learning, integration and considerable information-processing capacities may all have existed in pre-sentient ancestors. My hypothesis is that, at some point, affective states became part of the control system, providing a common currency through which signals and memories could be valued and used to guide behaviour. Under this view, there is a difference between a system in which something can feel good or bad and one in which nothing does, even though the capacities supporting that transition and the affective capacities that follow it are graded.
An analogy would be an exoplanet candidate. Astronomers may have evidence of varying strength that a planet exists around a distant star. Their confidence may be 20%, 70% or 99%, but the planet itself either exists or does not. Graded evidence does not require the underlying fact to be graded.
Likewise, the fact that behavioural, neural and physiological evidence exists on continua does not by itself imply that sentience must exist on a continuum. It means that our confidence about its presence is graded. This not requires assuming a simple or already known boundary in the evidential space. The biological transition may be complex, and we may be deeply uncertain about where it lies.
In your hypothetical, if we had both complete physical evidence and an adequate biological account of which forms of organization generate affective states, then yes: under my working view, the answer for a particular organism at a particular time would be either that affective experience was present or that it was absent. Our proposed classifications reflect our incomplete evidence and incomplete biological understanding, not a claim that the organism is partially sentient in proportion to our confidence.
This is also why the tool uses a sentience-plausibility gate followed by a separate affective-capacity analysis. The first asks whether there is sufficient reason to infer that anything can feel good or bad for the organism. The second asks, conditional on that, how differentiated and intense those states could be. The first is treated categorically in the underlying hypothesis but uncertain in our knowledge; the second is explicitly graded.
An analogy would be an exoplanet candidate. Astronomers may have evidence of varying strength that a planet exists around a distant star. Their confidence may be 20%, 70% or 99%, but the planet itself either exists or does not. Graded evidence does not require the underlying fact to be graded.
Looking into this example is helpful to explain my point. Humans have to come up with a defition for what is a planet, and then test whether a given celestial body satisfies it. Margot (2015) illustrates this. I present below their Figure 1 whose lines represents 3 potential definitons. They are analogous to the sharp evidential surface I mentioned in my last comment. Increasing the mass of a celestial body which is slightly too light to be a planet (just below the definitional line) by just 1 kg without practically changing its semi-major axis could make it a planet (cross the definitional line). I think this is fine. At the same time, I would not see any deep difference between 2 celestial bodies which are practically the same except one is 1 kg heavier, and therefore is a planet unlike the other.
My own personal view is that the biological capacities associated with sentience can vary continuously, while the minimal presence of affective experience [sentience] is categorical.
If sentience was categorical, there could in principle be 2 organisms which only differed infinitesimally in biological capacities, but one was sentient, and the other was not. This would be fine if sentience was similar to being a planet. However, sentience is often assumed to be necessary for moral consideration. In this case, one organism would get some moral value, and the other would get exactly 0 moral value. I would find this problematic if the organisms only differed infinitesimally.
This is also why the tool uses a sentience-plausibility gate followed by a separate affective-capacity analysis. The first asks whether there is sufficient reason to infer that anything can feel good or bad for the organism. The second asks, conditional on that, how differentiated and intense those states could be. The first is treated categorically in the underlying hypothesis but uncertain in our knowledge; the second is explicitly graded.
My take is that it would be better to have everything graded, and assume all organisms have more than exactly 0 moral value.
Thanks, Vasco. I think our respective positions are now becoming quite clear, and we may be reaching the point where further progress depends more on scientific and theoretical work than on extending the analogies.
My exoplanet example was intended only to distinguish graded evidence from the underlying fact being investigated. Whether a candidate celestial body exists is different from whether an already known body satisfies one of several proposed definitions of a planet. Margotâs figure addresses the latter question. My analogy concerned the former.
As I noted above, my position is that the biological capacities supporting sentience (and our evidence about them) can vary continuously even if the minimal presence of affective experience is categorical. What I would add here is that gradual evolution does not make such a transition implausible. Existing structures and capacities can be co-opted into a new functional role, as captured by the concept of exaptation: a feature that originally evolved for one function, or for no particular function, may later acquire another. This may make the evolutionary onset of sentience especially difficult to locate, because there need not be an obvious biological marker separating the earliest sentient organisms from their closest non-sentient relatives. The transition may have depended on a very small biological change, or even on a change in context that allowed existing mechanisms to perform a new role.
So yes: under my hypothesis, two organisms could in principle be extremely similar while affective experience was present in one and absent in the other. I do not find that paradoxical. A small difference in a complex system can sometimes make a new causal process possible. The supporting architecture may vary continuously even though the process we are asking about either occurs or does not occur in a particular organism at a particular time.
Your concern about one organism receiving some moral value while the other receives exactly none introduces a separate normative question. That conclusion does not follow automatically from the claim that sentience is categorical. The sentience gate in the tool is not intended to assign moral worth. Its focus is narrowerâand appropriately so, given that it concerns one of the biggest mysteries in science: it asks whether affective states, and therefore sentience in the relevant sense, plausibly occur in the target taxon.
Turning to the normative question, assuming that every organism has more than exactly zero moral value is a possible normative position, but it is not a scientific consequence of treating biological capacities as continuous. It would require its own justification.
Speaking only for myselfâand separately from the analytical commitments of the Welfare Footprint Frameworkâmy principal concern is severe suffering, particularly Disabling and Excruciating Pain. Annoying and Hurtful experiences remain genuine components of welfare and should be recorded in WFF analyses. But the presence of lower-intensity negative affect alone would not ordinarily make an organism or intervention a leading priority for me, especially given the scale of severe suffering that already exists and the need to consider where effective intervention is possible.
This is one reason the affective-ceiling question matters so much to me. Nature is not benign, and neither are most modern animal-production systems. Given the scale of severe suffering that already exists, I think our attention should be concentrated where the most intense suffering is possible. If biologically simpler sentient organisms have narrow affective ranges and cannot experience severe Pain, I would find that reassuring.
I therefore think our remaining disagreement concerns at least two distinct questions. Scientifically, you favor treating sentience itself as graded, whereas I regard its minimal presence as categorical while treating our evidenceâand subsequent affective range, resolution, and intensityâas graded. Normatively, you favor assigning every organism more than zero moral value, whereas my own priorities are concentrated on organisms capable of severe suffering, particularly where meaningful intervention is possible.
My exoplanet example was intended only to distinguish graded evidence from the underlying fact being investigated. Whether a candidate celestial body exists is different from whether an already known body satisfies one of several proposed definitions of a planet. Margotâs figure addresses the latter question. My analogy concerned the former.
I was analogising celestial bodies to organisms, and being a planet to being sentient. However, I also think whether a celestial body exists or not is a matter of human convention. I assume a clear definition would involve coming up with some properties like a minimum mass and density. In this case, one could come up with some amount of matter slighly too light to be a celestial body which would become a celestial body after adding it one more atom of hydrogen.
So yes: under my hypothesis, two organisms could in principle be extremely similar while affective experience was present in one and absent in the other. I do not find that paradoxical.
Even if the difference between the organisms can be arbitrarily small (not just extremely small, but arbitrarily close to a difference of exactly 0)? Supposing sentience is categorical/âsharp, 2 organisms could be equal in all regards except that one differs 10^-100 % along a single metric, and therefore is the only one of the 2 which is sentient.
A small difference in a complex system can sometimes make a new causal process possible. The supporting architecture may vary continuously even though the process we are asking about either occurs or does not occur in a particular organism at a particular time.
I agree for a âsmall differenceâ, but not for an arbitrarily small difference, and I think this is what distinguises sentience from lack of it if it is categorical/âsharp.
Scientifically, you favor treating sentience itself as graded, whereas I regard its minimal presence as categorical while treating our evidenceâand subsequent affective range, resolution, and intensityâas graded.
I believe sentience should be treated as graded if it means having a moral value above exactly 0. This is because I do not think an arbitrarily small difference should make an entity go from having exactly 0 moral value to having some moral value.
I am open to sentience being treated as binary if it does not mean having a moral value above exactly 0. However, in this case, lack of sentience would not imply lack of moral value.
Thanks, Vasco. I think your final paragraph shows that our positions are now closer than they initially appeared, and that part of the disagreement came from asking the word sentience to do two different jobs: describe whether affective experience is present, and determine whether an entity has non-zero moral value. In our tool, it is used only in the first sense.
On the scientific question, yes: under a categorical account of sentience, arbitrarily small changes near the relevant biological threshold could in principle place otherwise extremely similar organisms on opposite sides of it. I do not regard this as incoherent. Continuous underlying variables can produce categorical system-level events; a neuron, for example, may or may not fire an action potential as its membrane potential crosses a threshold. This analogy does not establish that sentience is categorical, but it shows that gradual biological change does not rule out a categorical onset.
The sentience gate in our tool therefore does not assign moral worth. It asks whether welfare-relevant affective experience is plausible enough for an affective-ceiling analysis to be meaningful. Whether entities without sentience may nevertheless have moral value, or whether moral status should vary continuously, are separate normative questions.
So perhaps our remaining scientific disagreement is now quite narrow: whether the minimal presence of affective experience is itself graded or categorical. On almost everything surrounding that boundary, however, we seem to agree: the biological capacities supporting sentience, our evidence for it, and the affective range, resolution, and intensity that follow are all graded. That is quite a lot of common ground! :) Thanks, Vasco, for the careful and constructive exchange.
On the scientific question, yes: under a categorical account of sentience, arbitrarily small changes near the relevant biological threshold could in principle place otherwise extremely similar organisms on opposite sides of it.
Would it make sense to run WFFâs affective capacity analysis for only one of 2 organisms which only differ infinitesimally?
I do not regard this [the sentence quoted above] as incoherent. Continuous underlying variables can produce categorical system-level events; a neuron, for example, may or may not fire an action potential as its membrane potential crosses a threshold. This analogy does not establish that sentience is categorical, but it shows that gradual biological change does not rule out a categorical onset.
I found this example quite thought-provoking. Yet, I do not think neuronal firings are categorical. Membrane potential and neuronal firings are represented in the mid and bottom plots of Figure 9A below from section 9.1 of the book Neuronal Dynamics. Membrane potential varies continuously. It is not binary. So humans have to come up with a convention for which types of variations in it count as a firing. In principle, 2 different time series of the membrane potential could differ infinitesimally, and one have 0 firings while other has many firings which fall just short of counting as such. If one was interested in a property like the maximum membrane potential, it would make sense to analyse both time series
There is also no fact of the matter about whether a given membrane potential corresponds to a neuronal firing or not. The number of neuronal firings is a property of the time series of the membrane potential. It is not a property of a neuronal state. In contrast, I understand sentience (existence of affective experiences) is supposed to be a property of a state (of an entity at a given time). Membrane potential is a property of a state, and it is continuous/âgraded (not binary/âcategorical/âsharp).
The physical world varies continuously. So I think all properties tracking it have to be continuous too. People point out phase transitions as evidence of categorical changes, but they involve continuous changes.
Would you keep the sentience gate in WFF if you thought it was a matter of human convention instead of scientific fact?
Thanks, Vasco. I had already acknowledged that the analogies were no longer helping, and then I fell into offering another one, so I concede that mistake. I do not think my underlying point is coming across, but I have laid it out as clearly as I can in our exchange. But just addressing your questions:
If one organism truly had affective experience and the other did not, the ceiling analysis would apply only to the former. For the latter, an affective ceiling would be inapplicable, not merely lower. If we could not tell which was which, the tool should reflect that uncertainty and proceed only conditionally.
(One clarification: this sentience gate belongs to our experimental Ψ approach, not to the core WFF).
Your final question captures the crux: if I regarded sentience as merely a matter of human convention, I would not retain it as a scientific gate. My position, as I mentioned before, is that whether anything feels good or bad is a real fact about the organism, even when we cannot determine it confidently.
I had already acknowledged that the analogies were no longer helping, and then I fell into offering another one, so I concede that mistake. I do not think my underlying point is coming across, but I have laid it out as clearly as I can in our exchange.
I personally found your analogy quite helpful. It gave me a chance to explain why I think many properties considered categorical are actually graded. In addition, I think trying to present properties which are categorical is important to illustrate sentience can be so too. The absence of any categorical properties would arguably be strong evidence against sentience being categorical.
Your final question captures the crux: if I regarded sentience as merely a matter of human convention, I would not retain it as a scientific gate.
Makes sense. I think sentience is a matter of human convention, which is why I would not use it as a scientific gate for the affective capacity analysis.
Hi Cynthia and Wladimir. Nice post.
You may be interested in the article âEthics Without Sentience: Facing Up to the Probable Insignificance of Phenomenal Consciousnessâ by François Kammerer. Here is a summary. Relatedly, you may like this and this very short posts by Keith Frankish. I agree with Keith that phenomenal consciousness does not exist. In any case, even if it exists, I agree with François it is not significant. Phenomenal consciousness as traditionally defined is not falsifiable (or, to be precise, it is traditionally defined such that one can only know about their own consciousness at the moment). In practice, one always has to come up with empirical proxies for it, but I feel these are largely arbitrary if it is not falsifiable. So I believe it would be better to focus just on what animals can do (as in your affective-capacity analysis), and not on assessing phenomenal sentience.
Thanks, Vasco â this is a very interesting challenge, and the pieces by Kammerer and Frankish are highly relevant.
I am not sure, however, that our use of sentience depends on the traditional conception of phenomenal consciousness that you are criticizing. In the Welfare Footprint Framework, the relevant question is whether an organism can have positive or negative affective statesâstates that can make its situation better or worse for it. We try to infer those states from converging behavioural, physiological, neural, pharmacological, cognitive, evolutionary, and ecological evidence.
This is why I would hesitate to focus only on what an organism can do. Behaviour and functional capacities are important evidence, but they are not themselves welfare. A biological or artificial system may avoid damage, learn, prioritize certain outcomes, and change its behaviour without anything necessarily feeling good or bad for it. The distinction between affective and non-affective control is therefore part of the question we are trying to investigate, rather than something we can simply set aside.
I would also hesitate to describe the empirical proxies as arbitrary. They are indirect and uncertain, and their interpretation depends partly on oneâs theory of consciousness. But some proxies are clearly more informative than others. Their value can be assessed through causal and comparative evidence, experimental interventions, and whether different classes of indicators point toward the same conclusion.
That said, your comment suggests a useful improvement to the tool. We could define the sentience gate more carefully and make clearer that it is not trying to identify an ineffable property disconnected from observable biological processes.
The workflow itself would remain the same. First, we ask whether the available evidence supports the existence of any positive or negative affective states. Only then, conditional on that assessment, do we ask how intense those states could plausibly become. These are related but distinct questions: the sentience gate concerns whether there is any affective welfare subject at all, whereas the ceiling analysis concerns the upper limit of that subjectâs affective range.
Some of the same evidence may inform both stages, but the inferential targets are different. We could make this distinction clearer in the article and in the tool, while also separating the observable evidence from the further inference about affective experience at each stage.
Someone sympathetic to Frankishâs view might interpret the same evidence without appealing to phenomenal properties as traditionally conceived. But for the WFF, we still need to distinguish systems that merely process information and regulate behaviour from organisms for which conditions can plausibly feel better or worse.
Thank you for drawing our attention to this. I think it may help us clarify both the article and the tool without changing the basic sequence of the analysis, and without requiring us to settle the broader philosophical debate before making practical progress.
Thanks, Wladimir.
Here is a thought experiment that may be helpful. Imagine you had all the empirical/âphysical evidence about an animal, including all the âbehavioural, physiological, neural, pharmacological, cognitive, evolutionary, and ecological evidenceâ. There may be practical limits to how much one could know, but I am imagining a scenario where empirical/âphysical uncertainty was fully eliminated. Would you be able to say whether the animal is sentient or not under the Welfare Footprint Framework (WFF)? If the probability of sentience is just supposed to capture empirical uncertainty under WFF, it would be either 0 or 1? For it to be higher than 0, and below 1, I think it would have to capture metaphysical or definitional uncertainty. If so, would it be better for WFF to cover just empirical uncertainty?
Under WFF, affective welfare either exists or does not exist at all. However, how can one justify such a binary distinction? Each type of empirical evidence, including âbehavioural, physiological, neural, pharmacological, cognitive, evolutionary, and ecological evidenceâ, exists on a spectrum. So I find it very counterintuitive that we could map empirical evidence to affective welfare either existing (sentience) or not existing at all (lack of sentience). I believe this would require assuming the existence of a sharp surface in the evidential space separating affective welfare existing from it not existing at all (even if there is uncertainty about the surface location), which is what feels arbitrary to me.
I should first clarify whose position is being discussed: The Welfare Footprint Framework itself does not prescribe a particular theory of sentience or affective capacity. It treats positive and negative affective experiences as the core of welfare, but it remains open about the precise biological mechanisms that produce them and about how affective capacities should ultimately be compared across species. The ideas in this series of posts are therefore better understood as our provisional contribution to this problem, developed largely for the practical purpose of making interspecific Welfare Footprint comparisons possible. They should not be presented as an official WFF position on whether sentience is categorical or graded.
My own personal view is that the biological capacities associated with sentience can vary continuously, while the minimal presence of affective experience is categorical. Nociception, memory, learning, integration and considerable information-processing capacities may all have existed in pre-sentient ancestors. My hypothesis is that, at some point, affective states became part of the control system, providing a common currency through which signals and memories could be valued and used to guide behaviour. Under this view, there is a difference between a system in which something can feel good or bad and one in which nothing does, even though the capacities supporting that transition and the affective capacities that follow it are graded.
An analogy would be an exoplanet candidate. Astronomers may have evidence of varying strength that a planet exists around a distant star. Their confidence may be 20%, 70% or 99%, but the planet itself either exists or does not. Graded evidence does not require the underlying fact to be graded.
Likewise, the fact that behavioural, neural and physiological evidence exists on continua does not by itself imply that sentience must exist on a continuum. It means that our confidence about its presence is graded. This not requires assuming a simple or already known boundary in the evidential space. The biological transition may be complex, and we may be deeply uncertain about where it lies.
In your hypothetical, if we had both complete physical evidence and an adequate biological account of which forms of organization generate affective states, then yes: under my working view, the answer for a particular organism at a particular time would be either that affective experience was present or that it was absent. Our proposed classifications reflect our incomplete evidence and incomplete biological understanding, not a claim that the organism is partially sentient in proportion to our confidence.
This is also why the tool uses a sentience-plausibility gate followed by a separate affective-capacity analysis. The first asks whether there is sufficient reason to infer that anything can feel good or bad for the organism. The second asks, conditional on that, how differentiated and intense those states could be. The first is treated categorically in the underlying hypothesis but uncertain in our knowledge; the second is explicitly graded.
Thanks for the clarifications.
Looking into this example is helpful to explain my point. Humans have to come up with a defition for what is a planet, and then test whether a given celestial body satisfies it. Margot (2015) illustrates this. I present below their Figure 1 whose lines represents 3 potential definitons. They are analogous to the sharp evidential surface I mentioned in my last comment. Increasing the mass of a celestial body which is slightly too light to be a planet (just below the definitional line) by just 1 kg without practically changing its semi-major axis could make it a planet (cross the definitional line). I think this is fine. At the same time, I would not see any deep difference between 2 celestial bodies which are practically the same except one is 1 kg heavier, and therefore is a planet unlike the other.
If sentience was categorical, there could in principle be 2 organisms which only differed infinitesimally in biological capacities, but one was sentient, and the other was not. This would be fine if sentience was similar to being a planet. However, sentience is often assumed to be necessary for moral consideration. In this case, one organism would get some moral value, and the other would get exactly 0 moral value. I would find this problematic if the organisms only differed infinitesimally.
My take is that it would be better to have everything graded, and assume all organisms have more than exactly 0 moral value.
Thanks, Vasco. I think our respective positions are now becoming quite clear, and we may be reaching the point where further progress depends more on scientific and theoretical work than on extending the analogies.
My exoplanet example was intended only to distinguish graded evidence from the underlying fact being investigated. Whether a candidate celestial body exists is different from whether an already known body satisfies one of several proposed definitions of a planet. Margotâs figure addresses the latter question. My analogy concerned the former.
As I noted above, my position is that the biological capacities supporting sentience (and our evidence about them) can vary continuously even if the minimal presence of affective experience is categorical. What I would add here is that gradual evolution does not make such a transition implausible. Existing structures and capacities can be co-opted into a new functional role, as captured by the concept of exaptation: a feature that originally evolved for one function, or for no particular function, may later acquire another. This may make the evolutionary onset of sentience especially difficult to locate, because there need not be an obvious biological marker separating the earliest sentient organisms from their closest non-sentient relatives. The transition may have depended on a very small biological change, or even on a change in context that allowed existing mechanisms to perform a new role.
So yes: under my hypothesis, two organisms could in principle be extremely similar while affective experience was present in one and absent in the other. I do not find that paradoxical. A small difference in a complex system can sometimes make a new causal process possible. The supporting architecture may vary continuously even though the process we are asking about either occurs or does not occur in a particular organism at a particular time.
Your concern about one organism receiving some moral value while the other receives exactly none introduces a separate normative question. That conclusion does not follow automatically from the claim that sentience is categorical. The sentience gate in the tool is not intended to assign moral worth. Its focus is narrowerâand appropriately so, given that it concerns one of the biggest mysteries in science: it asks whether affective states, and therefore sentience in the relevant sense, plausibly occur in the target taxon.
Turning to the normative question, assuming that every organism has more than exactly zero moral value is a possible normative position, but it is not a scientific consequence of treating biological capacities as continuous. It would require its own justification.
Speaking only for myselfâand separately from the analytical commitments of the Welfare Footprint Frameworkâmy principal concern is severe suffering, particularly Disabling and Excruciating Pain. Annoying and Hurtful experiences remain genuine components of welfare and should be recorded in WFF analyses. But the presence of lower-intensity negative affect alone would not ordinarily make an organism or intervention a leading priority for me, especially given the scale of severe suffering that already exists and the need to consider where effective intervention is possible.
This is one reason the affective-ceiling question matters so much to me. Nature is not benign, and neither are most modern animal-production systems. Given the scale of severe suffering that already exists, I think our attention should be concentrated where the most intense suffering is possible. If biologically simpler sentient organisms have narrow affective ranges and cannot experience severe Pain, I would find that reassuring.
I therefore think our remaining disagreement concerns at least two distinct questions. Scientifically, you favor treating sentience itself as graded, whereas I regard its minimal presence as categorical while treating our evidenceâand subsequent affective range, resolution, and intensityâas graded. Normatively, you favor assigning every organism more than zero moral value, whereas my own priorities are concentrated on organisms capable of severe suffering, particularly where meaningful intervention is possible.
I was analogising celestial bodies to organisms, and being a planet to being sentient. However, I also think whether a celestial body exists or not is a matter of human convention. I assume a clear definition would involve coming up with some properties like a minimum mass and density. In this case, one could come up with some amount of matter slighly too light to be a celestial body which would become a celestial body after adding it one more atom of hydrogen.
Even if the difference between the organisms can be arbitrarily small (not just extremely small, but arbitrarily close to a difference of exactly 0)? Supposing sentience is categorical/âsharp, 2 organisms could be equal in all regards except that one differs 10^-100 % along a single metric, and therefore is the only one of the 2 which is sentient.
I agree for a âsmall differenceâ, but not for an arbitrarily small difference, and I think this is what distinguises sentience from lack of it if it is categorical/âsharp.
I believe sentience should be treated as graded if it means having a moral value above exactly 0. This is because I do not think an arbitrarily small difference should make an entity go from having exactly 0 moral value to having some moral value.
I am open to sentience being treated as binary if it does not mean having a moral value above exactly 0. However, in this case, lack of sentience would not imply lack of moral value.
Thanks, Vasco. I think your final paragraph shows that our positions are now closer than they initially appeared, and that part of the disagreement came from asking the word sentience to do two different jobs: describe whether affective experience is present, and determine whether an entity has non-zero moral value. In our tool, it is used only in the first sense.
On the scientific question, yes: under a categorical account of sentience, arbitrarily small changes near the relevant biological threshold could in principle place otherwise extremely similar organisms on opposite sides of it. I do not regard this as incoherent. Continuous underlying variables can produce categorical system-level events; a neuron, for example, may or may not fire an action potential as its membrane potential crosses a threshold. This analogy does not establish that sentience is categorical, but it shows that gradual biological change does not rule out a categorical onset.
The sentience gate in our tool therefore does not assign moral worth. It asks whether welfare-relevant affective experience is plausible enough for an affective-ceiling analysis to be meaningful. Whether entities without sentience may nevertheless have moral value, or whether moral status should vary continuously, are separate normative questions.
So perhaps our remaining scientific disagreement is now quite narrow: whether the minimal presence of affective experience is itself graded or categorical. On almost everything surrounding that boundary, however, we seem to agree: the biological capacities supporting sentience, our evidence for it, and the affective range, resolution, and intensity that follow are all graded. That is quite a lot of common ground! :) Thanks, Vasco, for the careful and constructive exchange.
Would it make sense to run WFFâs affective capacity analysis for only one of 2 organisms which only differ infinitesimally?
I found this example quite thought-provoking. Yet, I do not think neuronal firings are categorical. Membrane potential and neuronal firings are represented in the mid and bottom plots of Figure 9A below from section 9.1 of the book Neuronal Dynamics. Membrane potential varies continuously. It is not binary. So humans have to come up with a convention for which types of variations in it count as a firing. In principle, 2 different time series of the membrane potential could differ infinitesimally, and one have 0 firings while other has many firings which fall just short of counting as such. If one was interested in a property like the maximum membrane potential, it would make sense to analyse both time series
There is also no fact of the matter about whether a given membrane potential corresponds to a neuronal firing or not. The number of neuronal firings is a property of the time series of the membrane potential. It is not a property of a neuronal state. In contrast, I understand sentience (existence of affective experiences) is supposed to be a property of a state (of an entity at a given time). Membrane potential is a property of a state, and it is continuous/âgraded (not binary/âcategorical/âsharp).
The physical world varies continuously. So I think all properties tracking it have to be continuous too. People point out phase transitions as evidence of categorical changes, but they involve continuous changes.
Would you keep the sentience gate in WFF if you thought it was a matter of human convention instead of scientific fact?
Thanks, Vasco. I had already acknowledged that the analogies were no longer helping, and then I fell into offering another one, so I concede that mistake. I do not think my underlying point is coming across, but I have laid it out as clearly as I can in our exchange. But just addressing your questions:
If one organism truly had affective experience and the other did not, the ceiling analysis would apply only to the former. For the latter, an affective ceiling would be inapplicable, not merely lower. If we could not tell which was which, the tool should reflect that uncertainty and proceed only conditionally.
(One clarification: this sentience gate belongs to our experimental Ψ approach, not to the core WFF).
Your final question captures the crux: if I regarded sentience as merely a matter of human convention, I would not retain it as a scientific gate. My position, as I mentioned before, is that whether anything feels good or bad is a real fact about the organism, even when we cannot determine it confidently.
I personally found your analogy quite helpful. It gave me a chance to explain why I think many properties considered categorical are actually graded. In addition, I think trying to present properties which are categorical is important to illustrate sentience can be so too. The absence of any categorical properties would arguably be strong evidence against sentience being categorical.
Makes sense. I think sentience is a matter of human convention, which is why I would not use it as a scientific gate for the affective capacity analysis.