Seth holds that consciousness only emerges when predictive processing is embedded in systems that regulate themselves to stay alive. That means no consciousness in non-biological systems. I am about to argue that functionalism should be the default view and that there is currently no alternative to functionalism. That means no reason to believe that biology is necessary for consciousness.
A theory of consciousness ought to distinguish between conscious and unconscious states. Seth’s positive proposal does not meet this minimal criterion. There is no evidence that the machinery he proposes is specifically operative in conscious states, as opposed to unconscious states, or in conscious organisms, as opposed to unconscious ones.
Start with free energy minimization. Granted, conscious organisms might have a knack for minimizing free energy. But so do sponges, bacteria and yeast. Free energy minimization is so ubiquitous that it would be shocking if unconscious mental processes weren’t in on the game too. The same thing goes for predictive coding. Even if the brain is a predictive engine and conscious states result from predictive coding, there is no evidence that unconscious mental processes do not follow similar principles. Nothing here properly distinguishes conscious from unconscious states.
The biological processes by which we regulate our living bodies are even worse in that respect. Seth writes that “we experience the world, and the self, with, through, and because of our living bodies.” No doubt. But we also digest, keep breathing under general anesthesia, maintain posture, fight infections, regulate body temperature, and sleep dreamlessly through, and because of our living bodies. Biology is full of unconscious goings-on. So there’s no reason to link consciousness to autopoiesis, and some reason not to.
Of course, Seth doesn’t need to give us a biological property that distinguishes conscious from unconscious states. All he needs is to make the case for the necessity of biology. So, could biology be necessary?
For better or worse, computational functionalism is a view in metaphysics. The relevant kind of necessity is metaphysical necessity. Seth’s arguments do not establish the metaphysical necessity of biology and thus are harmless against computational functionalism.
Think about currency. A thing can’t be currency unless it is divisible, portable, durable, and in limited supply. Suppose only gold meets those conditions. Gold would, as a matter of fact, be the only currency. Yet, “being a currency” could still be identical to having the right functional role. If some other stuff had done the job of being a unit of account, store of value, and means of exchange, it would have been a currency. Being a currency could be identical to a functional role, even if only gold fulfills that role.
Back to consciousness. The question is: if a non-biological system were to perform the same functions as a conscious biological one, would it have conscious experiences? Seth argues that, as a matter of fact, non-biological systems cannot perform the same functions as conscious biological systems. Maybe so, but this does not answer the question. The difference between conscious and unconscious states could still be a matter of functional roles, even if only biological systems can perform the relevant functions.
Are we at a standstill? I don’t think so. Because there is currently no alternative explanatory framework that can hold a candle to computational functionalism. Let me give two reasons why.
First, functionalism wins on induction. When we explain other psychological capacities – mental arithmetic, language production, causal inference, memory retrieval, etc. – we do it functionally. We appeal to computations over mental representations, not special biological properties. Mental kinds are individuated by functional roles (Fodor, Reference Fodor1974; Weiskopf, Reference Weiskopf2011), not by properties of the neurobiological kinds that realize them. By induction, we should expect that the difference between conscious and unconscious mental states is also a matter of functional role. That is, we should expect that differences in mental kinds are functional differences through and through, including the difference between conscious and unconscious states. Of course, consciousness might be the exception. But as Damon Runyon put it, paraphrasing Ecclesiastes: “The race is not always to the swift, nor the battle to the strong, but that’s how the smart money bets.” And that’s partly why we should bet on functionalism.
Second, consider a variety of consciousness-related phenomena: object-substitution masking, blindsight, binocular rivalry, change blindness, inattentional blindness, Troxler fading, visual suppression with transcranial magnetic stimulation to V1, the attentional blink, motion-induced blindness, and so on. These phenomena are of interest for consciousness researchers because they involve (or at least they’re supposed to involve) consciously perceiving a stimulus at one time and unconsciously registering it at another. A theory of consciousness ought to explain why. Here again, the only contenders are computational functionalist theories: global workspace theory (Mashour et al., Reference Mashour, Roelfsema, Changeux and Dehaene2020), higher-order theories (Brown, Lau, & LeDoux, Reference Brown, Lau and LeDoux2019), and so on. No biological theory on the market explains these contrasts by appealing to some property unique to living systems. Seth might say predictive processing can do the job. Maybe it can. But predictive processing is defined computationally. So once again, functional role and computation do the heavy explanatory lifting, not biology.
As things stand, our best theory of mental kinds and our best theories of the differences between conscious and unconscious states make no appeal to biological properties. That being the case, we have no reason to believe that biology matters except insofar as it constrains the implementation of the right functional roles. Maybe someday we’ll discover a biological property that fits the bill – one that explains the whole range of relevant phenomena. That day, I’ll happily convert. Until then, the smart money is on functionalism, for the same reason that you bet on the swift and the strong. They don’t always win, but they usually do.
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Seth holds that consciousness only emerges when predictive processing is embedded in systems that regulate themselves to stay alive. That means no consciousness in non-biological systems. I am about to argue that functionalism should be the default view and that there is currently no alternative to functionalism. That means no reason to believe that biology is necessary for consciousness.
A theory of consciousness ought to distinguish between conscious and unconscious states. Seth’s positive proposal does not meet this minimal criterion. There is no evidence that the machinery he proposes is specifically operative in conscious states, as opposed to unconscious states, or in conscious organisms, as opposed to unconscious ones.
Start with free energy minimization. Granted, conscious organisms might have a knack for minimizing free energy. But so do sponges, bacteria and yeast. Free energy minimization is so ubiquitous that it would be shocking if unconscious mental processes weren’t in on the game too. The same thing goes for predictive coding. Even if the brain is a predictive engine and conscious states result from predictive coding, there is no evidence that unconscious mental processes do not follow similar principles. Nothing here properly distinguishes conscious from unconscious states.
The biological processes by which we regulate our living bodies are even worse in that respect. Seth writes that “we experience the world, and the self, with, through, and because of our living bodies.” No doubt. But we also digest, keep breathing under general anesthesia, maintain posture, fight infections, regulate body temperature, and sleep dreamlessly through, and because of our living bodies. Biology is full of unconscious goings-on. So there’s no reason to link consciousness to autopoiesis, and some reason not to.
Of course, Seth doesn’t need to give us a biological property that distinguishes conscious from unconscious states. All he needs is to make the case for the necessity of biology. So, could biology be necessary?
For better or worse, computational functionalism is a view in metaphysics. The relevant kind of necessity is metaphysical necessity. Seth’s arguments do not establish the metaphysical necessity of biology and thus are harmless against computational functionalism.
Think about currency. A thing can’t be currency unless it is divisible, portable, durable, and in limited supply. Suppose only gold meets those conditions. Gold would, as a matter of fact, be the only currency. Yet, “being a currency” could still be identical to having the right functional role. If some other stuff had done the job of being a unit of account, store of value, and means of exchange, it would have been a currency. Being a currency could be identical to a functional role, even if only gold fulfills that role.
Back to consciousness. The question is: if a non-biological system were to perform the same functions as a conscious biological one, would it have conscious experiences? Seth argues that, as a matter of fact, non-biological systems cannot perform the same functions as conscious biological systems. Maybe so, but this does not answer the question. The difference between conscious and unconscious states could still be a matter of functional roles, even if only biological systems can perform the relevant functions.
Are we at a standstill? I don’t think so. Because there is currently no alternative explanatory framework that can hold a candle to computational functionalism. Let me give two reasons why.
First, functionalism wins on induction. When we explain other psychological capacities – mental arithmetic, language production, causal inference, memory retrieval, etc. – we do it functionally. We appeal to computations over mental representations, not special biological properties. Mental kinds are individuated by functional roles (Fodor, Reference Fodor1974; Weiskopf, Reference Weiskopf2011), not by properties of the neurobiological kinds that realize them. By induction, we should expect that the difference between conscious and unconscious mental states is also a matter of functional role. That is, we should expect that differences in mental kinds are functional differences through and through, including the difference between conscious and unconscious states. Of course, consciousness might be the exception. But as Damon Runyon put it, paraphrasing Ecclesiastes: “The race is not always to the swift, nor the battle to the strong, but that’s how the smart money bets.” And that’s partly why we should bet on functionalism.
Second, consider a variety of consciousness-related phenomena: object-substitution masking, blindsight, binocular rivalry, change blindness, inattentional blindness, Troxler fading, visual suppression with transcranial magnetic stimulation to V1, the attentional blink, motion-induced blindness, and so on. These phenomena are of interest for consciousness researchers because they involve (or at least they’re supposed to involve) consciously perceiving a stimulus at one time and unconsciously registering it at another. A theory of consciousness ought to explain why. Here again, the only contenders are computational functionalist theories: global workspace theory (Mashour et al., Reference Mashour, Roelfsema, Changeux and Dehaene2020), higher-order theories (Brown, Lau, & LeDoux, Reference Brown, Lau and LeDoux2019), and so on. No biological theory on the market explains these contrasts by appealing to some property unique to living systems. Seth might say predictive processing can do the job. Maybe it can. But predictive processing is defined computationally. So once again, functional role and computation do the heavy explanatory lifting, not biology.
As things stand, our best theory of mental kinds and our best theories of the differences between conscious and unconscious states make no appeal to biological properties. That being the case, we have no reason to believe that biology matters except insofar as it constrains the implementation of the right functional roles. Maybe someday we’ll discover a biological property that fits the bill – one that explains the whole range of relevant phenomena. That day, I’ll happily convert. Until then, the smart money is on functionalism, for the same reason that you bet on the swift and the strong. They don’t always win, but they usually do.
Acknowledgments
I thank Ali Rezaei.
Financial support
This research received no specific grant from any funding agency, commercial, or not-for-profit sectors.
Competing interests
None.