Hereâs a thought experiment similar to Kaganâs that I expect could get different responses from people:
There are humans for which pain is not unpleasant (pain asymbolia). However, suppose one such child has been taught to act as if their pain is unpleasant. They will cry out, plead to make it stop, do things to avoid pain, talk about pain as if itâs unpleasant, and so on, with consistently appropriate responses. To anyone who doesnât know they have pain asymbolia, the child seems to experience pain like any other.
That child and a typical (non-asymbolic) child are injured and both need surgery. The surgery for the typical child would be very painful to them. The surgery the asymbolic child needs would be even more painful than the surgery the non-asymbolic child needs, if performed on a typical non-asymbolic child. You only have enough painkillers to totally eliminate the pain in one of the surgeries (if performed on a non-asymbolic child, who finds pain unpleasant in the typical ways), or even less than that. The painkillers also have diminishing marginal returns to greater dosages.
How do you split the painkillers between the two children?
The right answer here seems to be to give all of the painkillers to the typical/ânon-asymbolic child, and none to the child with pain asymbolia, no matter how much more painful the surgery the asymbolic child needs would typically be for non-asymbolic people, if weâre ~100% sure the asymbolic child is fully (or almost fully) asymbolic. We know from their history that they didnât respond to pain in the right way, and only came to do so due to being taught to act like it. Maybe theyâre also missing some physiological responses to unpleasant pain, e.g. heart rate, tears, stress hormones, neural responses, but maybe theyâve found a way to fake some of those.[1]
I think this would get different responses from people partly because Iâve made it much more concrete why the child does not find pain unpleasant in a way thatâs easy to entertain and believe. âour best science reveals to usâcorrectlyâthat they are not sentientâ is pretty vague. Why should I believe that our best science is correct in general or about this case in particular?
This case is interesting, but I think it touches on a slightly different issue. The symbolic presumably doesnât care about their pretend pain. There is a more complicated story about their actions that involves their commitment to the ruse. In the robot case, I assume weâre supposed to imagine that the robots care about each other to whatever extent that unconscious things can. Their motivational structure is close to ours.
I think the case is less clear if we build up the extent to which the asymbolic child really wants the painkillers. If they constantly worry about not getting them, if they are willing to sacrifice lots of other things they care about to secure them (even though they know that it wonât help them avoid pain), etc. Iâm less inclined to think the case is clear cut.
In the robot case, I assume weâre supposed to imagine that the robots care about each other to whatever extent that unconscious things can.
I think so, but without more detail about what exactly theyâre missing, my intuitive reaction is that they are conscious or reasonably likely to be conscious. Itâs hard to trust or entertain the hypothetical. How could they not be conscious?
If you fill in the details in specific ways, then you might get different responses. If the robots are like todayâs LLMs or a giant lookup table, then Iâm inclined to say they arenât really conscious to any significant degree: theyâve been designed (or assumed into existence) by Goodharting the behavioural outputs of conscious beings.
Thereâs another question about whether Iâd actually dissect one, and maybe I still wouldnât, but this could be for indirect or emotional reasons. It could still be very unpleasant or even traumatic for me to dissect something that cries out and against the desperate pleas of its mother. Or, it could be bad to become less sensitive to such responses, when such responses often are good indicators of risk of morally significant harm. People who were confident nonhuman animals donât matter in themselves sometimes condemned animal cruelty for similar reasons.
Or, maybe the robotsâ consciousness is very probably minimal, but still enough to warrant some care. This could be in line with how many people treat insects or spiders: they wouldnât give up much to help them, but they might still take them outside when found inside or otherwise avoid killing them when the costs are very low.
If they constantly worry about not getting them, if they are willing to sacrifice lots of other things they care about to secure them (even though they know that it wonât help them avoid pain), etc. Iâm less inclined to think the case is clear cut.
This could all follow from a great commitment to pretending to be capable of unpleasant pain like a typical person.
I guess if theyâre subjectively worse off the less convincing they think they are to others, they could be worse off finding out they wonât get painkillers, if and because they find out they failed to convince you.
You could just lie and say there arenât any painkillers available, but then this gets into the issue of whether they care about actually being convincing, or just believing theyâre convincing (contact with reality, experience machine, etc.), and which of the two you care about on their behalf.
It is rare for theories of consciousness to make any demands on motivational structure.
Global workspace theory, for instance, says that consciousness depends on having a central repository by which different cognitive modules talk to each other. If the modules were to directly communicate point to point, there would be no conscious experiences (by that theory). I see no reason in that case why decision making would have to rely on different mechanisms.
Higher order theories suggest that consciousness depends on having representations of our own mental states. A creature could have all sorts of direct concerns that it never reflected on, and these could look a lot like ours.
IIT suggests that you could have a high level duplicate of a conscious system that was unconscious due to the fine grained details.
Etc.
The specific things you need to change in the robots to render them not conscious depends on your theory, but I donât think you need to go quite so far as to make them a lookup table or an transformer.
My impression was that you like theories that stress the mechanisms behind our judgments of the weirdness of consciousness as critical to conscious experiences. I could imagine a robot just like us but totally non-introspective, lacking phenomenal concepts, etc. Would you think such a thing was conscious? Could it not desire things in something like the way we do?
Thereâs another question about whether Iâd actually dissect one, and maybe I still wouldnât, but this could be for indirect or emotional reasons. It could still be very unpleasant or even traumatic for me to dissect something that cries out and against the desperate pleas of its mother. Or, it could be bad to become less sensitive to such responses, when such responses often are good indicators of risk of morally significant harm. People who were confident nonhuman animals donât matter in themselves sometimes condemned animal cruelty for similar reasons.
This supports my main argument. If you value conscious experience these emotional reasons could be concerning for the long term future. It seems like a slippery slope from being nice to them because we find it more pleasant to thinking that they are moral patients, particularly if we frequently interact with them. It is possible that our generation will never stop caring about consciousness, but if weâre not careful, our children might.
FWIW, I meant âHow could they not be conscious?â kind of rhetorically, but I appreciate your response. Making it more concrete like this is helpful. My comment here is pretty object-level about the specific views in question, so feel free not to respond to it or any specific points here.
Global workspace theory (...)
There probably still needs to be âworkspacesâ, e.g. working memory (+ voluntary attention?), or else the robots couldnât do many sophisticated things flexibly, and whatever those workspaces are could be global workspaces. Maybe each module has its own workspace, so is âglobalâ to itself, and thatâs enough. Or, if the workspaces are considered together as one combined system, then it could be a more conventional âglobal workspaceâ, just distributed. The differences donât seem significant at this level of abstraction. Maybe they are, but Iâd want to know why. So, my direct intuitive reaction to âGWT is true and the robots arenât consciousâ could be unreliable, because itâs hard to entertain.
Higher order theories suggest that consciousness depends on having representations of our own mental states. A creature could have all sorts of direct concerns that it never reflected on, and these could look a lot like ours.
I think this one is more plausible and easier to entertain, although still weird.
I think it means that if you asked the mother robot if she cares about her child, she wouldnât say âyesâ (she might say ânoâ or be confused). It seems the robots would all have complete alexithymia, and not just for emotions, but for all mental states, or at least all (the components of) mental states that could matter, e.g. valence, desires, preferences. But theyâd still be intelligent and articulate. The mother would have no concept of desire, preference, caring, etc., or sheâd be systematically unable to apply such concepts to herself, even though she might apply it to her child, e.g. she distinguishes her child from a âmere thingâ, and I imagine she recognizes that her child cares about things.
Or, maybe it could depend on the particulars of whatâs required of a higher order representation according to theory. The mother robot might have and apply a concept of desire, preference, caring, etc. to herself, but itâs not the right kind of higher order representation.
IIT suggests that you could have a high level duplicate of a conscious system that was unconscious due to the fine grained details.
IIT is pretty panpsychist in practice, just needing recurrence, IIRC. I donât think you would have a complex society of intelligent robots without recurrence (networks of purely feedforward interactions would end up far too large, but the recurrence might be extended beyond their brains). And at any rate, IIT seems way off track to me as a theory. So, my direct intuitive reaction to âIIT is true and the robots arenât consciousâ will probably be unreliable.
My impression was that you like theories that stress the mechanisms behind our judgments of the weirdness of consciousness as critical to conscious experiences. I could imagine a robot just like us but totally non-introspective, lacking phenomenal concepts, etc. Would you think such a thing was conscious? Could it not desire things in something like the way we do?
There are a few âlinesâ that seem potentially morally significant to me as an illusionist:
As you mention, having and applying phenomenal concepts, or having illusions of phenomenal consciousness, e.g. finding aspects of our perceptions/âinformation processing weird/âmysterious/âcurious/âineffable (or unphysical, private and/âor intrinsic, etc., although thatâs getting more specific, and thereâs probably more disagreement on this). I agree the robots could fail to matter in this way.
Having states that would lead to illusions of phenomenal consciousness or the application of phenomenal concepts to them, finding them weird/âmysterious/âcurious, etc., if those states were introspected on by a sufficiently sophisticated system in the right way (even if the existing system is incapable of introspection; we consider a hypothetical attaching another system to do it). This is Frankishâs and I suspect Dennettâs normative interpretation of illusionism, and their views of consciousness are highly graded. Maybe just cognitive impenetrability suffices, if/âbecause the cognitive impenetrability of the things we introspect is what makes them seem weird/âmysterious/âcurious/âineffable to us.[1] Iâd guess the robots would matter in this way.
The appearances of something mattering, in causal/âfunctional terms â including desires, pleasure, unpleasantness, preferences, moral intuitions, normative beliefs, etc. â just are phenomenal illusions or (the application of) phenomenal concepts, or parts of phenomenal illusions or phenomenal concepts that matter even on their own. Itâs not just that consciousness seems weird (etc.), but that part of our phenomenal concepts for (morally relevant) conscious mental states is just that they seem to matter. And, in fact, itâs the appearance of mattering that makes the mental states matter morally, not the apparent weirdness (etc.). We wouldnât care (much) about a personâs specific experience of red unless they cared about it, too. An experience only matters morally in itself if it seems to matter to the individual, e.g. the individual takes a specific interest in it, or finds it pleasant, unpleasant, attractive, aversive, significant, etc.. Furthermore, itâs not important that that âseeming to matterâ applies to mental states in a higher-order way rather than âdirectlyâ to the intentional objects of mental states, like in the robotsâ desires; thatâs an arbitrary line.[2] The robots seem to matter in this way.
1 implies 2, and I suspect 3 implies 2, as well.
I also suspect we canât answer which of 1, 2 or 3 is (objectively, stance-independently) correct. It seems inherently normative and subjective (and Iâm not a moral realist), although Iâve become pretty sympathetic to 3, basically for the reasons I give in 3. We could also go for a graded account of moral status, where each of 1, 2 and 3 ground different degrees of moral status.
Humphrey, another illusionist, said âConsciousness matters because it is its function to matterâ. However, heâs skeptical animals other than mammals and birds are conscious. He thinks consciousness requires finding your own mental states/âperceptions/âsensations to matter, e.g. engaging in sensation-seeking or sensory play. Such animals find their perceptions themselves interesting, not just the intentional objects of those perceptions. So itâs higher order-ish.
I think that would get different responses, but I donât think it is quite as good a thought experiment because it probably doesnât approximate the likely future as well as the other thought experiment.
Future AI is likely to look like nothing at all (in a computer), or look like a non-human entity, perhaps a robot. I agree that an entity looking and acting basically exactly the same as a human would illicit very different emotional and practical responses from us, but it seems very unlikely that is how we encounter early-stage future ânon-consciousâ AGI or however we want to call it.
My thought experiment was aimed at showing that direct intuitive responses to such thought experiments are irrationally sensitive to framing and how concrete the explanations are.
The asymbolic child is almost identical to a typical child and acts the same way, so you would think people would be less hesitant to dismiss their apparent pain than a robotâs. But I would guess people dismiss the asymbolic childâs pain more easily.
My explanation for why the asymbolic childâs pain doesnât matter (much) actually shouldnât make you more sure of the fact than the explanation given in the robot case. Iâve explained how and why the child is asymbolic, but in the robot case, weâve just said âour best science reveals to usâcorrectlyâthat they are not sentientâ. âcorrectlyâ means 100% certainty that they arenât sentient. Making the explanation more concrete makes it more believable, easier to entertain and easier for intuitions to reflect appropriately. But it doesnât make it more probable!
However, on reflection, these probably push the other way and undermine my claim of irrational intuitive responses:
My opportunity cost framing, e.g. thinking itâs better to give the painkillers to the typical child doesnât mean you would normally want to perform surgery on the asymbolic child without painkillers, if theyâre cheap and not very supply-limited and the asymbolic child would protest less (pretend to be in pain less) if given painkillers.
People arenât sure moral patienthood requires sentience, a still vague concept that may evolve into something they donât take to be necessary, but theyâre pretty sure that the pain responses in the asymbolic child donât indicate something that matters much, whatever the correct account of moral patienthood and value. It can be easier to identify and be confident in specific negative cases than put trust in a rule separating negative and positive cases.
Hereâs a thought experiment similar to Kaganâs that I expect could get different responses from people:
There are humans for which pain is not unpleasant (pain asymbolia). However, suppose one such child has been taught to act as if their pain is unpleasant. They will cry out, plead to make it stop, do things to avoid pain, talk about pain as if itâs unpleasant, and so on, with consistently appropriate responses. To anyone who doesnât know they have pain asymbolia, the child seems to experience pain like any other.
That child and a typical (non-asymbolic) child are injured and both need surgery. The surgery for the typical child would be very painful to them. The surgery the asymbolic child needs would be even more painful than the surgery the non-asymbolic child needs, if performed on a typical non-asymbolic child. You only have enough painkillers to totally eliminate the pain in one of the surgeries (if performed on a non-asymbolic child, who finds pain unpleasant in the typical ways), or even less than that. The painkillers also have diminishing marginal returns to greater dosages.
How do you split the painkillers between the two children?
The right answer here seems to be to give all of the painkillers to the typical/ânon-asymbolic child, and none to the child with pain asymbolia, no matter how much more painful the surgery the asymbolic child needs would typically be for non-asymbolic people, if weâre ~100% sure the asymbolic child is fully (or almost fully) asymbolic. We know from their history that they didnât respond to pain in the right way, and only came to do so due to being taught to act like it. Maybe theyâre also missing some physiological responses to unpleasant pain, e.g. heart rate, tears, stress hormones, neural responses, but maybe theyâve found a way to fake some of those.[1]
I think this would get different responses from people partly because Iâve made it much more concrete why the child does not find pain unpleasant in a way thatâs easy to entertain and believe. âour best science reveals to usâcorrectlyâthat they are not sentientâ is pretty vague. Why should I believe that our best science is correct in general or about this case in particular?
Maybe we should worry that theyâve actually come to find pain unpleasant, either because of the teaching, or independently of it.
Or maybe we should worry that the diagnosis of pain asymbolia was wrong in the first place.
In that case, we might want to give some of the painkillers to the apparently asymbolic child.
This case is interesting, but I think it touches on a slightly different issue. The symbolic presumably doesnât care about their pretend pain. There is a more complicated story about their actions that involves their commitment to the ruse. In the robot case, I assume weâre supposed to imagine that the robots care about each other to whatever extent that unconscious things can. Their motivational structure is close to ours.
I think the case is less clear if we build up the extent to which the asymbolic child really wants the painkillers. If they constantly worry about not getting them, if they are willing to sacrifice lots of other things they care about to secure them (even though they know that it wonât help them avoid pain), etc. Iâm less inclined to think the case is clear cut.
I think so, but without more detail about what exactly theyâre missing, my intuitive reaction is that they are conscious or reasonably likely to be conscious. Itâs hard to trust or entertain the hypothetical. How could they not be conscious?
If you fill in the details in specific ways, then you might get different responses. If the robots are like todayâs LLMs or a giant lookup table, then Iâm inclined to say they arenât really conscious to any significant degree: theyâve been designed (or assumed into existence) by Goodharting the behavioural outputs of conscious beings.
Thereâs another question about whether Iâd actually dissect one, and maybe I still wouldnât, but this could be for indirect or emotional reasons. It could still be very unpleasant or even traumatic for me to dissect something that cries out and against the desperate pleas of its mother. Or, it could be bad to become less sensitive to such responses, when such responses often are good indicators of risk of morally significant harm. People who were confident nonhuman animals donât matter in themselves sometimes condemned animal cruelty for similar reasons.
Or, maybe the robotsâ consciousness is very probably minimal, but still enough to warrant some care. This could be in line with how many people treat insects or spiders: they wouldnât give up much to help them, but they might still take them outside when found inside or otherwise avoid killing them when the costs are very low.
This could all follow from a great commitment to pretending to be capable of unpleasant pain like a typical person.
I guess if theyâre subjectively worse off the less convincing they think they are to others, they could be worse off finding out they wonât get painkillers, if and because they find out they failed to convince you.
You could just lie and say there arenât any painkillers available, but then this gets into the issue of whether they care about actually being convincing, or just believing theyâre convincing (contact with reality, experience machine, etc.), and which of the two you care about on their behalf.
It is rare for theories of consciousness to make any demands on motivational structure.
Global workspace theory, for instance, says that consciousness depends on having a central repository by which different cognitive modules talk to each other. If the modules were to directly communicate point to point, there would be no conscious experiences (by that theory). I see no reason in that case why decision making would have to rely on different mechanisms.
Higher order theories suggest that consciousness depends on having representations of our own mental states. A creature could have all sorts of direct concerns that it never reflected on, and these could look a lot like ours.
IIT suggests that you could have a high level duplicate of a conscious system that was unconscious due to the fine grained details.
Etc.
The specific things you need to change in the robots to render them not conscious depends on your theory, but I donât think you need to go quite so far as to make them a lookup table or an transformer.
My impression was that you like theories that stress the mechanisms behind our judgments of the weirdness of consciousness as critical to conscious experiences. I could imagine a robot just like us but totally non-introspective, lacking phenomenal concepts, etc. Would you think such a thing was conscious? Could it not desire things in something like the way we do?
This supports my main argument. If you value conscious experience these emotional reasons could be concerning for the long term future. It seems like a slippery slope from being nice to them because we find it more pleasant to thinking that they are moral patients, particularly if we frequently interact with them. It is possible that our generation will never stop caring about consciousness, but if weâre not careful, our children might.
FWIW, I meant âHow could they not be conscious?â kind of rhetorically, but I appreciate your response. Making it more concrete like this is helpful. My comment here is pretty object-level about the specific views in question, so feel free not to respond to it or any specific points here.
There probably still needs to be âworkspacesâ, e.g. working memory (+ voluntary attention?), or else the robots couldnât do many sophisticated things flexibly, and whatever those workspaces are could be global workspaces. Maybe each module has its own workspace, so is âglobalâ to itself, and thatâs enough. Or, if the workspaces are considered together as one combined system, then it could be a more conventional âglobal workspaceâ, just distributed. The differences donât seem significant at this level of abstraction. Maybe they are, but Iâd want to know why. So, my direct intuitive reaction to âGWT is true and the robots arenât consciousâ could be unreliable, because itâs hard to entertain.
I think this one is more plausible and easier to entertain, although still weird.
I think it means that if you asked the mother robot if she cares about her child, she wouldnât say âyesâ (she might say ânoâ or be confused). It seems the robots would all have complete alexithymia, and not just for emotions, but for all mental states, or at least all (the components of) mental states that could matter, e.g. valence, desires, preferences. But theyâd still be intelligent and articulate. The mother would have no concept of desire, preference, caring, etc., or sheâd be systematically unable to apply such concepts to herself, even though she might apply it to her child, e.g. she distinguishes her child from a âmere thingâ, and I imagine she recognizes that her child cares about things.
Or, maybe it could depend on the particulars of whatâs required of a higher order representation according to theory. The mother robot might have and apply a concept of desire, preference, caring, etc. to herself, but itâs not the right kind of higher order representation.
IIT is pretty panpsychist in practice, just needing recurrence, IIRC. I donât think you would have a complex society of intelligent robots without recurrence (networks of purely feedforward interactions would end up far too large, but the recurrence might be extended beyond their brains). And at any rate, IIT seems way off track to me as a theory. So, my direct intuitive reaction to âIIT is true and the robots arenât consciousâ will probably be unreliable.
There are a few âlinesâ that seem potentially morally significant to me as an illusionist:
As you mention, having and applying phenomenal concepts, or having illusions of phenomenal consciousness, e.g. finding aspects of our perceptions/âinformation processing weird/âmysterious/âcurious/âineffable (or unphysical, private and/âor intrinsic, etc., although thatâs getting more specific, and thereâs probably more disagreement on this). I agree the robots could fail to matter in this way.
Having states that would lead to illusions of phenomenal consciousness or the application of phenomenal concepts to them, finding them weird/âmysterious/âcurious, etc., if those states were introspected on by a sufficiently sophisticated system in the right way (even if the existing system is incapable of introspection; we consider a hypothetical attaching another system to do it). This is Frankishâs and I suspect Dennettâs normative interpretation of illusionism, and their views of consciousness are highly graded. Maybe just cognitive impenetrability suffices, if/âbecause the cognitive impenetrability of the things we introspect is what makes them seem weird/âmysterious/âcurious/âineffable to us.[1] Iâd guess the robots would matter in this way.
The appearances of something mattering, in causal/âfunctional terms â including desires, pleasure, unpleasantness, preferences, moral intuitions, normative beliefs, etc. â just are phenomenal illusions or (the application of) phenomenal concepts, or parts of phenomenal illusions or phenomenal concepts that matter even on their own. Itâs not just that consciousness seems weird (etc.), but that part of our phenomenal concepts for (morally relevant) conscious mental states is just that they seem to matter. And, in fact, itâs the appearance of mattering that makes the mental states matter morally, not the apparent weirdness (etc.). We wouldnât care (much) about a personâs specific experience of red unless they cared about it, too. An experience only matters morally in itself if it seems to matter to the individual, e.g. the individual takes a specific interest in it, or finds it pleasant, unpleasant, attractive, aversive, significant, etc.. Furthermore, itâs not important that that âseeming to matterâ applies to mental states in a higher-order way rather than âdirectlyâ to the intentional objects of mental states, like in the robotsâ desires; thatâs an arbitrary line.[2] The robots seem to matter in this way.
1 implies 2, and I suspect 3 implies 2, as well.
I also suspect we canât answer which of 1, 2 or 3 is (objectively, stance-independently) correct. It seems inherently normative and subjective (and Iâm not a moral realist), although Iâve become pretty sympathetic to 3, basically for the reasons I give in 3. We could also go for a graded account of moral status, where each of 1, 2 and 3 ground different degrees of moral status.
In defense of the necessity of the cognitive impenetrability of illusions of phenomenal consciousness, see Kammerer, 2022.
Humphrey, another illusionist, said âConsciousness matters because it is its function to matterâ. However, heâs skeptical animals other than mammals and birds are conscious. He thinks consciousness requires finding your own mental states/âperceptions/âsensations to matter, e.g. engaging in sensation-seeking or sensory play. Such animals find their perceptions themselves interesting, not just the intentional objects of those perceptions. So itâs higher order-ish.
I think that would get different responses, but I donât think it is quite as good a thought experiment because it probably doesnât approximate the likely future as well as the other thought experiment.
Future AI is likely to look like nothing at all (in a computer), or look like a non-human entity, perhaps a robot. I agree that an entity looking and acting basically exactly the same as a human would illicit very different emotional and practical responses from us, but it seems very unlikely that is how we encounter early-stage future ânon-consciousâ AGI or however we want to call it.
My thought experiment was aimed at showing that direct intuitive responses to such thought experiments are irrationally sensitive to framing and how concrete the explanations are.
The asymbolic child is almost identical to a typical child and acts the same way, so you would think people would be less hesitant to dismiss their apparent pain than a robotâs. But I would guess people dismiss the asymbolic childâs pain more easily.
My explanation for why the asymbolic childâs pain doesnât matter (much) actually shouldnât make you more sure of the fact than the explanation given in the robot case. Iâve explained how and why the child is asymbolic, but in the robot case, weâve just said âour best science reveals to usâcorrectlyâthat they are not sentientâ. âcorrectlyâ means 100% certainty that they arenât sentient. Making the explanation more concrete makes it more believable, easier to entertain and easier for intuitions to reflect appropriately. But it doesnât make it more probable!
However, on reflection, these probably push the other way and undermine my claim of irrational intuitive responses:
My opportunity cost framing, e.g. thinking itâs better to give the painkillers to the typical child doesnât mean you would normally want to perform surgery on the asymbolic child without painkillers, if theyâre cheap and not very supply-limited and the asymbolic child would protest less (pretend to be in pain less) if given painkillers.
People arenât sure moral patienthood requires sentience, a still vague concept that may evolve into something they donât take to be necessary, but theyâre pretty sure that the pain responses in the asymbolic child donât indicate something that matters much, whatever the correct account of moral patienthood and value. It can be easier to identify and be confident in specific negative cases than put trust in a rule separating negative and positive cases.