Challenges for the third week
Look for evidences in favour or against the sensorymotor coupling, that is the hypothesis that perceptual and motor systems evolved and works as one.
I neuroni specchio e la “comprensione” dell’azione«La pianificazione di un’azione richiede la previsione delle conseguenze. Ciò significa che quando stiamo per eseguire una data azione, siamo altresì in grado di prevederne le conseguenze. Questo tipo di predizione è il risultato dell’attività del modello di azione. Se fosse possibile stabilire un processo di equivalenza motoria tra ciò che è agito e ciò che viene percepito, grazie all’attivazione dello stesso substrato neuronale in entrambe le situazioni, una forma diretta di comprensione dell’azione altrui si renderebbe possibile. La ricerca neuroscientifica ci dice che le cose stanno proprio così. Il nostro cervello è infatti dotato di neuroni - i neuroni specchio - localizzati nella corteccia premotoria e parietale posteriore, che si attivano sia quando compiamo un’azione sia quando la vediamo eseguire da altri. Sia le predizioni che riguardano le nostre azioni, sia quelle che riguardano le azioni altrui, possono quindi essere caratterizzate come processi di modellizzazione fondati sulla simulazione. La stessa logica che presiede alla modellizzazione delle nostre azioni presiede anche quella delle azioni altrui. Percepire un’azione - e comprenderne il significato - equivale a simularla internamente. Ciò consente all’osservatore di utilizzare le proprie risorse per penetrare il mondo dell’altro mediante un processo di modellizzazione che ha i connotati di un meccanismo non conscio, automatico e pre-linguistico di simulazione motoria» [da Vittorio Gallese, “Corpo vivo, simulazione incarnata e intersoggettività”, in M. Cappuccio (a cura di), Neurofenomenologia. Le scienze della mente e la sfida dell’esperienza cosciente, Mondadori, Milano, 2006, pag. 304-305]
I NEURONI SPECCHIO
Tipologia di neuroni la cui esistenza è stata rilevata per la prima volta verso la metà degli anni ‘90 da Giacomo Rizzolatti e colleghi presso il dipartimento di neuroscienze dell’Università di Parma. Utilizzando come soggetti sperimentali dei macachi, questi ricercatori osservarono che alcuni gruppi di neuroni si attivavano non solo quando gli animali erano intenti a determinate azioni, ma anche quando guardavano qualcun altro compiere le stesse azioni.
Studi successivi, effettuati con tecniche non invasive, hanno dimostrato l’esistenza di sistemi simili anche negli uomini. Sembrerebbe che essi interessino diverse aree cerebrali, comprese quelle del linguaggio.
I neuroni specchio permettono di spiegare fisiologicamente la nostra capacità di porci in relazione con gli altri. Quando osserviamo un nostro simile compiere una certa azione si attivano, nel nostro cervello, gli stessi neuroni che entrano in gioco quando siamo noi a compiere quella stessa azione. Per questo possiamo comprendere con facilità le azioni degli altri: nel nostro cervello si accendono circuiti nervosi che richiamano analoghe azioni compiute da noi in passato.
Quest’ultima precisazione è molto importante. Infatti sembrerebbe che il “sistema specchio” entri in azione soltanto quando il soggetto osserva un comportamento che egli stesso ha posto in atto in precedenza. Ad esempio, si è visto che in un danzatore classico i neuroni specchio si attivano esclusivamente di fronte a una esibizione di danza classica, e non di fronte al ballo moderno, e viceversa.
Anche il riconoscimento delle emozioni sembra poggiare su un insieme di circuiti neurali che, per quanto differenti, condividono quella proprietà “specchio” già rilevata nel caso della comprensione delle azioni. E’ stato possibile studiare sperimentalmente alcune emozioni primarie: i risultati mostrano che quando osserviamo negli altri una manifestazione di dolore o di disgusto si attiva il medesimo substrato neuronale collegato alla percezione in prima persona dello stesso tipo di emozione. Un’altra conferma viene da studi clinici su pazienti affetti da patologie neurologiche: una volta perduta la capacità di provare un’emozione non si è più in grado di riconoscerla quando viene espressa da altri.
Vi sono infine alcune evidenze sperimentali che sembrano indicare che anche la comprensione del linguaggio faccia riferimento, almeno per certi aspetti, a meccanismi di “risonanza” che coinvolgono il sistema motorio. Comprendere una frase che esprime un’azione provoca probabilmente un’attivazione degli stessi circuiti motori chiamati in causa durante l’effettiva esecuzione di quell’azione.
La scoperta dei neuroni specchio potrebbe offrire una spiegazione biologica per almeno alcune forme di autismo, come, ad esempio, la sindrome di Asperger: in effetti, gli esperimenti in tal senso finora condotti sembrerebbero indicare un ridotto funzionamento di questo tipo di neuroni nei bambini autistici. Benché per ora si tratti soltanto di un’ipotesi, essa potrebbe aiutare a comprendere perché le persone autistiche non partecipano alla vita degli altri, non riescono ad entrare in sintonia con il mondo che li circonda, non capiscono il significato dei gesti e delle azioni altrui. Probabilmente non comprendono neppure le più comuni emozioni espresse dal volto e dagli atteggiamenti di coloro che li circondano: quello che per tutti è un sorriso, per loro potrebbe essere una semplice smorfia.
L’esistenza dei neuroni specchio prospetta la necessità di una profonda modifica nelle attuali concezioni riguardanti il modo di operare della nostra mente. Sicuramente tale scoperta implica un drastico ridimensionamento del modello di mente prospettato dalla psicologia cognitivista (vedi cognitivismo), basato sull’analogia funzionale con i calcolatori. Questo tipo di approccio concentra i propri sforzi soprattutto nel definire le regole formali che sarebbero alla base del funzionamento della mente, ignorando completamente il ruolo dell’esperienza corporea legata al comportamento motorio. I neuroni specchio implicano infatti l’esistenza di un meccanismo che consente di comprendere immediatamente il significato delle azioni altrui e persino delle intenzioni ad esse sottese senza porre in atto alcun tipo di ragionamento.
Le ricerche sui neuroni specchio sono ancora agli inizi, ma è probabile - come osserva il neuroscienziato Vilayanur Ramachandran - che si tratti di una delle più importanti scoperte degli ultimi decenni, destinata ad avere profonde ripercussioni nel nostro modo di concepire la mente.
INTERVISTA A GIACOMO RIZZOLATTI
Challenges for the third week
Look for evidences in favour or against the sensorymotor coupling, that is the hypothesis that perceptual and motor systems evolved and works as one.
Un esempio di integrazione sensomotoria può essere ritrovato nei processi di elaborazione musicale, essendo questo un processo che richiede un’integrazione tra processi percettivi ed esecutivi. L’articolo a cui fa riferimento il link inserito di seguito (e che invito a consultare per una chiarificazione sulle metodologie e gli strumenti utilizzati oltre che per un maggiore dettaglio circa le conclusioni ottenute) fa riferimento ad un interessante esperimento effettuato per cercare di comprendere ed analizzare le dinamiche che si vengono a creare nei legami tra percezione ed azione, confrontando variabili diverse: gesto musicale, notazione e suono. L’esperimento si propone di misurare gli effetti sull’azione prodotti da stimoli uditivi musicali congruenti o incongruenti con le note da eseguire. Secondo l’interpretazione degli autori, che hanno registrato tempi di reazione più lunghi nel caso di stimoli incongruenti, il suono pre-attiverebbe la rappresentazione motoria necessaria alla produzione dello stesso, causando così una facilitazione o un’inibizione nell’esecuzione.
Challenge for the first week
What is a scientific theory of the mind (of the mental life); and in what is it similar/different in their components/structure to theories of other natural phenomena like the ones occurring in physics, biology?
As a General Term, Phenomenal Property Has no Ontological Status
Chienchih Chi, July 21, 2003
SPCW 2003 Conference, Santa Fe, New Mexico
Scientific theories and natural phenomena
Science is supposed to be theories or explanations of natural phenomena. I assume that if there is a natural phenomenon, then there is a possible cognitive mechanism that can (form a scientific theory to) explain or understand this phenomenon. Thus, if something X is impossible for any possible cognitive mechanism to form a scientific theory to explain it, then X is not a natural phenomenon. This definition denies the possibility that there is something in the ontological world, but totally unrecognizable by any possible cognitive mechanism. Thus, if we know that there is no possible scientific theory or understanding for X, then we can reach the conclusion that X is not a natural phenomenon.
What does it mean to say that X is, or is not a natural phenomenon? This needs more explanations. For example, the formula E = MC2 is a scientific theory that expresses a relation between natural phenomena E (energy), M (mass), and C (the speed of light). We believe that energy, mass and the speed of light are natural phenomena. Taking energy as an example, there are a lot of different types of energies, but we can consider them to belong to the same thing called energy. There is at least one respect or property that is shared among those different energies, and we use the general (or abstract) term energy to refer to this property. Although we may not find any individual entity that exactly matches the general term, we can still consider the general term as referring to a natural phenomenon or natural property. However, if there is no shared property among different types of energies, then there is no way to consider the general term energy as a natural phenomenon, which means that the term energy refers to nothing in the world.
A natural phenomenon plays a causal or functional role in the world. We can create a scientific theory (e.g. E = MC2) to describe its role or relations with other natural phenomena. If all causal roles can be explained in a theory, then this theory is the complete causal explanation of the world. This kind of theory is generally believed possible. But, even if we can produce this kind of theory, we cannot still explain phenomenal properties of the mind.
The problem of the irreducibility of the mind
In order to explain phenomenal properties scientifically, we encounter the problem of the irreducibility of the mind. Searle indicates that no matter how we use physical (or physiological) concepts to explain, for instance, the feeling of pain, there is always something left unexplained (Searle 1992, p.117). We call these unexplainable mental properties qualia, subjective qualities, or phenomenal properties. Based on Nagel’s explanation, phenomenal properties are purely subjective (from the first-person point of view) and physical concepts are absolutely objective (from the third-person point of view). Objective concepts do not contain any content that can reduce or explain subjective concepts. This is why we cannot use physical (or third-person) concepts to thoroughly explain the mind (Nagel 1986). Since all scientific concepts are third-person concepts, we cannot thoroughly explain the mind with a scientific theory.
Although today’s science is based on a third-person point of view, it is not necessary for a scientific theory to adopt a third-person point of view. The goal of science is to find out the real nature of the world. If the real nature of the world cannot be described through a certain approach (a third-person point of view), then we should use other approaches to grasp it. If we can go beyond this limitation, there may be hope for us to create a theory to solve the hard problem that can explain how the physical can give rise to the mental. However, even if such a theory to solve the hard problem exists, McGinn argues that the theory is beyond human cognition. This shows that human cognition has its limitation; there is something that cannot be grasped by human cognitive mechanisms (McGinn 1989). Chalmers also argues that there is no reducible explanation of phenomenal properties (or consciousness) through physical properties or concepts. No set of facts about physical structure and dynamics can add up to a fact about phenomenal properties (Chalmers 1996, p.118). This implies that the hard problem is insolvable in a reductive way. Thus, he suggests that a complete scientific theory (a true theory of everything or a final theory) will have both components: physical laws for physical phenomena and psychological laws for mental phenomena (Chalmers 1995b). Thus, both the physical and the mental are fundamental components. A new science that can deal with the hard problem should employ a fundamental law (component) for the phenomenal properties (or consciousness) (Chalmers 1995b). Thus, this new science won’t be totally objective or based on a third-person point of view. Is this the solution to the problem of the irreducibility of the mind? I think it may be a solution for the human mind, but it cannot be an adequate solution for all possible minds. This means that Chalmers’ suggestion cannot be used to create a complete scientific theory of the mind, which supposes to explain the mind in general rather than only the human mind.
In this paper, I will argue that a complete scientific theory of the mind that includes all possible phenomenal properties is not only beyond human cognition but also beyond any possible cognitive mechanism, because such a theory cannot possibly exist. According to the ontological definition previously mentioned, this implies that there is no natural phenomenon that corresponds to consciousness or phenomenal property when we understand them as general terms in the first-person point of view.
Reconsider McGinn’s Suggestion
When the solution to a problem is beyond our cognition, is it still possible for us to know that no possible cognitive mechanism can solve the problem? I believe so. There are other problems that are also beyond human cognition and we can believe that they are also beyond any possible cognitive mechanism, because we have reasons to believe that the theory that can solve the problem does not possibly exist. For example, can we find an answer to the question of how many ponds of sugar equal to a three-foot-tree? We cannot find an answer because there is no answer. Since there is no answer, there is no theory that can solve this problem. Thus, no possible cognitive mechanism can create a scientific theory to solve it. Based on the ontological definition previously mentioned, we can also say that the natural law (or natural phenomenon) that is supposed to answer the question does not exist. Thus, the best solution to the problem is to explain why there is no answer. Thus, we can solve (or simply deal with) this problem by pointing out that weight and length are totally different paradigms to which there is nothing to compare.
Although it is reasonable to believe that human cognition has its limitations, we cannot reach McGinn’s conclusion simply by finding one question that cannot be answered. If there is a nature phenomenon that is principally not understandable by human cognitive mechanisms, then it is meaningful to claim that human cognition has its limitation. But if the question does not correctly ask something about natural phenomena, then what we need to do is to find out where the question goes wrong. The problem might be in conceptual frameworks that are used to construct the question or in some of our ontological presuppositions. For example, when we try to reduce the mental to the physical, we have presupposed that the physical is more fundamental than the mental, but how can we make such a presupposition and how can we compare their ontological statuses? The irreducibility between the physical and the mental may only show a conceptual or epistemological problem rather than an ontological one. If the hard problem is simply generated from conceptual frameworks, then it is not proper to say that the hard problem cannot be solved by human cognition. It is better to say that we do not correctly ask the question about the ontological world. Based on the ontological definition previously mentioned, when we say that a solution to the hard problem doesn’t possibly exist for any possible cognitive mechanism, it means that there is no natural phenomenon that corresponds to the problem. Thus, there is no scientific theory that can explain the nonexistent phenomenon. Thus, the solution or the best way to deal with the hard problem may be to try to find out how to avoid the problem or simply to point out why we encounter this problem.
Two types of scientific theories of the mind
There could be two types of scientific theory of the mind. One is called causal reduction, in which we may use physical (or third-person) concepts to thoroughly explain mental properties in the functional or causal respect. The causal reduction is believed to be easier than (or possible as compared to) the hard problem. If we do not adopt eliminative materialism, it seems that there is no problem to believe that consciousness or phenomenal properties can correspond to brain processes. Thus, an understanding of the brain could result in a scientific theory of the mind or consciousness in the causal or functional respect. I will call this the scientific theory of the mind F, or simply theory F.
The other type is a scientific theory of the mind that can thoroughly explain the mind not only in its functional respect, but also in its phenomenal respect. In order to create such a theory we must either solve the hard problem that is an explanation of how the physical can give rise to the mental or, as Chalmers suggests, adopt the non-reductive strategy that we should give fundamental laws to the mental. Either theory can be considered a complete theory of the mind because either one does not suppose to leave phenomenal properties unexplained. I will call this kind of theory the scientific theory of the mind P, or simply theory P. Thus, theory P can thoroughly explain the mind both in the functional and phenomenal respects.
Theory P does not possibly exist
Suppose we have already produced theory F. This means that we can use third-person (or physical) concepts to thoroughly explain first-person (or mental) concepts in the functional respect. With this theory, we will know what kind of physical structure can correspond to a phenomenal property in a cognitive mechanism. Although we haven’t produced this theory yet, based on today’s knowledge, it would be reasonable to believe that the following statements are true in theory F:
- Different types of phenomenal properties correspond to different physical structures.
It is reasonable to believe that different types of phenomenal properties (e.g. red and sour) correspond to different physical structures. Take the human brain as an example: evidence shows that there are different areas corresponding to different types of phenomenal properties. The same area may not be able to produce (or correspond to) different types of phenomenal properties. In addition, based on first-person knowledge, we cannot find anything similar between a taste and a color in their phenomenal properties. It is reasonable to believe that if both of them can correspond to physical structures, the structures must be different, or systematically different.
However, physical structure is probably not a good term for describing the physical aspect that corresponds to phenomenal properties. Dynamic physical process is probably a better one because it is highly possible (at least for the human brain) that phenomenal properties correspond to dynamic brain processes. As Edelman and Tononi indicate, each phenomenal property (or quale) corresponds to a different state of the dynamic core, which can be differentiated from billions of other states within a neural space comprising a large number of dimensions (Edelman & Tononi 2000, p.157). However, in order to develop a scientific theory of the mind, we are discussing phenomenal properties in general rather than only human phenomenal properties. Using physical structure can describe more general phenomena. We can still use physical structure to mean structures that can produce dynamic physical processes. Since different physical components may produce different dynamic physical processes that may correspond to different phenomenal properties, we have more reason to believe this statement.
- There are infinite possible (systematically different) physical structures that can correspond to phenomenal properties.
When we know which physical structure corresponds to which phenomenal property in a causal explanation, we should know how to create a new physical structure that can correspond to a new type of phenomenal property. Thus, it is reasonable to believe that the number of physical structures that can correspond to different types of phenomenal properties could be infinite.
- There are infinite types of possible phenomenal properties.
Since different physical structures that can correspond to different types of phenomenal properties could be infinite, there are infinite possible phenomenal properties.
It seems reasonable to believe that all of the statements above are correct. Then, we can have the following argument:
Suppose we create a computer being whose cognitive mechanism can produce a physical structure that corresponds to a phenomenal property C that is not possessed by human beings. Do we think that theory P must include the property C?
If we think so, since C could be any possible phenomenal property, theory P must include all possible phenomenal properties. However, there is no such theory or there is no such cognitive mechanism that can produce such a theory. We can make a thought experiment to show this.
Suppose alien 1 possesses cognitive mechanism K that can produce theory P, which can thoroughly explain phenomenal properties. In this case, we can ask whether alien 1 knows what it is like for human beings to be in pain. If the cognitive mechanism K is similar to human beings’, then alien 1 knows what it is like for human beings to be in pain. But since theory P is beyond human cognition (because human beings do not possess the property C), it should also be beyond cognitive mechanism K. Thus, alien 1 cannot create or understand theory P. But if the cognitive mechanism K is not similar to human’s, then alien 1 does not know what it is like for human beings to be in pain. Thus, alien 1 cannot still create or understand theory P, which is supposed to include an explanation of human phenomenal properties. The other possibility is that the cognitive mechanism K includes human cognition. In this case, there will be no problem. But, can the cognitive mechanism K include all different physical structures that correspond to all types of phenomenal properties? Since the possible types of phenomenal properties could be infinite and a cognitive mechanism cannot include infinite different structures that correspond to all infinite types of phenomenal properties, the cognitive mechanisms that can subjectively explain all possible phenomenal properties do not possibly exist. Based on the discussions above, we can conclude that theory P does not possibly exist, or the mechanism K that can generate or understand theory P does not possibly exist. It is not only beyond human cognition as McGinn suggests, but also beyond all possible cognitive mechanisms.
However, if we don’t think that theory P must include the property C, then theory P cannot explain some possible phenomenal properties. In this situation, the scientific theory is not a general theory, which cannot be called a scientific theory or at least cannot be called a complete theory.
There are two ways to grasp all possible phenomenal properties. One is to include all of them in a cognitive mechanism, by which to form a theory. But, we have showed that it is impossible. The other way is to grasp a shared property among them. If we consider phenomenal property as a general term, there may be something we can grasp among different types of phenomenal properties. Based on their shared features, we can use the general term to create a theory. However, we may only grasp something in the functional respect, but not in the phenomenal respect. Thus, a scientific theory of the mind may only explain their functional respects and ignore the phenomenal respects.
Based on the discussion above, we can conclude that theory P does not possibly exist or the cognitive mechanism that can understand or produce theory P does not exist. Since a theory can only exist in a cognitive mechanism, if such a mechanism does not possibly exist, then it is the same to say that the theory does not possibly exist.
In other words, like energy, the general or abstract term phenomenal property is supposed to grasp some common features among different phenomenal properties like pain, sour, red, and etc. However, they don’t have any phenomenal similarity, but only functional similarity. The general term phenomenal property can only refer to something functional rather than phenomenal. Thus, when we try to produce a scientific theory to generally solve the hard problem, we try to reduce something non-existent into the physical world. However, the hard problem for individual phenomenal properties is still a meaningful problem, but it needs different considerations, which are not a concern of this paper.
Chalmers, D. (1995a). “Facing Up to the Problem of Consciousness,” Journal of Consciousness Studies, Vol. 2, pp. 200-219.
Chalmers, D. (1995b). “The Puzzle of Conscious Experience,” Scientific American, December 1995, pp. 62-68.
Chalmers, D. (1996). The Conscious Mind: In Search of a Fundamental Theory, Oxford: Oxford University Press.
Edelman, G. M. & Tononi, G. (2000). A Universe of Consciousness: How Matter Becomes Imagination, New York: Basic Books.
McGinn, C. (1989). “Can We Solve the Mind-Body Problem?” Mind, Vol.98, pp.349-366.
Searle, J. R. (1992). The Rediscovery of the Mind, Cambridge, Massachusetts: The MIT Press.
 Chalmers (1995a) distinguishes the problem of consciousness (or the problem of the mind) into two parts: easy problems and the hard problem. The easy problems are about mental functions and the hard problem is about phenomenal properties.
 For example, Searle believes that “consciousness is a causally emergent property of the behavior of neurons, and so consciousness is causally reducible to the brain processes (Searle 1992, p.116).” In addition, Nagel believes it is not irrational to hope that people will be able to observe the operation of the brain and say, with true understanding, “That’s what the experience of tasting chocolate looks like from the outside” (Nagel 1998, p.337).
 I say, “phenomenal properties correspond to brain processes” rather than “phenomenal properties are generated from brain processes” because I don’t want to presuppose that the physical is more fundamental than the mental. We can temporarily put them in a parallel position without presupposing which one is more fundamental than the other. Thus, the “reduction” may not be ontological but epistemological or conceptual.