Significato del logos e significato degli elementi nel Teeteto e nel Cratilo di Platone

For Plato, the basic tool of philosophical knowledge is logos, not only in the general sense of "reason," but also in the specific sense of knowledge attained by means of "discourse", namely a reason that has a fundamentally linguistic character. This seems to imply that the logos is entirely transparent to itself; and consequently, as we can deduce from the analysis consecrated in the Theaetetus to the so called "theory of the dream", that the elements of which the logos is composed are fully intelligible and devoid of any opacity. However, this claim seems to fail in the Cratylus, where the attempt to show the intelligibility of the elements of language, i.e. letters and syllables, does not succeed. A possible solution to this problem lies in the fact that the elements of language, unlike the natural elements, exhaust their nature in the role they play within the language itself; and therefore the knowledge of this role, just as in the case of the pieces of chess, coincides with the knowledge of the element as a whole.Pour Platon l'instrument principal de la connaissance philosophique est le logos, non seulement dans le sens g\ue9n\ue9ral de \uab raison \ubb, mais aussi dans le sens sp\ue9cifique de connaissance qui se r\ue9alise au moyen du \uab discours \ubb, c'est \ue0 dire d'une raison qui poss\ue8de un caract\ue8re fonci\ue8rement linguistique. Cela semble impliquer que le logos a une nature enti\ue8rement transparente \ue0 soi m\ueame, et par cons\ue9quent, comme on peut le d\ue9duire de l'analyse consacr\ue9e dans le Th\ue9\ue9t\ue8te \ue0 la th\ue9orie du songe, que les \ue9l\ue9ments dont le logos est compos\ue9 sont pleinement intelligibles et d\ue9pourvus de toute opacit\ue9. Cependant cette pr\ue9tention semble \ue9chouer dans le Cratyle, o\uf9 la tentative de montrer l'intelligibilit\ue9 des \ue9l\ue9ments du langage, c'est \ue0 dire lettres et syllabes, n'est pas couronn\ue9e de succ\ue8s. Une possible solution \ue0 ce probl\ue8me repose sur le fait que les \ue9l\ue9ments du langage, \ue0 la diff\ue9rence des \ue9l\ue9ments naturels, \ue9puisent enti\ue8rement leur nature dans le r\uf4le qu'ils jouent \ue0 l'int\ue9rieur du langage lui-m\ueame ; et donc la connaissance de ce r\uf4le, exactement comme il en est des pi\ue8ces des \ue9checs, co\uefncide avec la connaissance de l'objet dans son entier

Heidegger e l'idea platonica del bene: storia di una amicizia fallita

Dans un travail anterieur j\u2019ai essaye de montrer que Heidegger a finalement refuse de faire place, dans sa philosophie, a la notion platonicienne d\u2019idee, bien qu\u2019elle semblait, selon un certain point de vue, etre une figure capable de representer l\u2019ouverture originelle de l\u2019\ueatre qui \ue9tait au coeur des recherches de Heidegger dans les annees qui entourent Etre et Temps. La raison de cela, a mon avis, est que l\u2019approche aristotelicienne de la philosophie de Platon par Heidegger explicitement adoptee conduisait au bout du compte a interpreter l\u2019idee de Platon comme une substance (et donc comme une figure de l\u2019etant et non pas de l\u2019etre). Mais qu\u2019en est\u2011il de l\u2019idee du bien, qui pour sa determination teleologique et pour sa collocation au\u2011dela de l\u2019ousia d\u2019un cote semblait repondre aux besoins propres a la pensee heideggerienne, et d\u2019un autre cote etait plus refractaire a la substantialisation aristotelicienne (la Verdinglichung de P. Natorp) ? La these que je soutiens est que Heidegger, tout en ayant cultive pour longtemps le projet d\u2019utiliser l\u2019idee du bien comme un precedent important de son ontologie, a finalement decide que ce projet n\u2019etait pas possible, parce que la connotation ethique de cette idee (qui non seulement ne l\u2019interessait pas, mais qu\u2019il detestait ouvertement) etait largement dominante sur l\u2019aspect ontologique

Odisseo e Achille nell'Ippia Minore: esempi di un dibattito morale

Nell'Ippia Minore, soprattutto nella sua ultima parte, Platone sembra voler sostenere che chi \ue8 in grado di sbagliare volontariamente (ad esempio mentire) \ue8 migliore, sul piano morale, di chi non lo sa fare; e dunque, contrariamente all'opinione condivisa in modo pressoch\ue9 unanime nella cultura greca, che la subdola e spesso ingannevole astuzia di Odisseo \ue8 superiore, sempre dal punto di vista morale, alla sincera e semplice schiettezza di Achille. La maggior parte della critica ha trovato imbarazzante ammettere che Platone sostenesse una tesi di questo genere, e ha dunque tentato in vari modi di correre ai ripari. La strategia pi\uf9 usata \ue8 la seguente: giacch\ue9 il principio secondo cui chi sbaglia volontariamente \ue8 migliore \ue8 valido solo in rapporto alle tecniche, Platone starebbe cercando di dimostrare o che l'etica non \ue8 una tecnica, oppure che per quella tecnica che \ue8 l'etica il principio in questione non vale. Ma si tratta di un punto di vista insostenibile, perch\ue9 contrario sia alla lettera sia al significato del testo. Nell'Ippia minore, cos\uec come molti altri dialoghi (non solo giovanili), quello che Platone vuol dimostrare, in chiara polemica contro l'etica tradizionale che affondava le sue radici proprio nel modello etico che potremmo chiamare epico - omerico (quello, appunto, in cui era sancita la superiorit\ue0 morale di Achille su Odisseo), \ue8 che dal punto di vista formale l'etica (e pi\uf9 in generale la filosofia, considerato l'intento pratico che essa ha in Platone) \ue8 una tecnica esattamente come le altre: \ue8 la tecnica, in particolare, che ha come suo scopo quello di produrre la felicit\ue0, ovvero la vita buona (del resto tutto questo \ue8 gi\ue0 implicito nel motto socratico secondo cui la virt\uf9 \ue8 conoscenza). E poich\ue9 non \ue8 pensabile una tecnica in cui l'esperto non abbia un sapere sufficiente per commettere errori, necessariamente ne consegue che il principio incriminato \ue8 valido anche per l'etica e per la filosofia: chi \ue8 in grado di compiere il male volontariamente \ue8 migliore di chi non lo sa fare. Naturalmente se da qui ricavassimo la conseguenza che il virtuoso fa sia il male sia il bene volontariamente, mentre il vizioso, non potendo fare il male, fa volontariamente solo il bene, avremmo raggiunto una conclusione assurda. Ma in realt\ue0 la frase in oggetto \ue8 doppiamente falsa. In primo luogo il vizioso non fa il bene volontariamente: infatti il motivo per cui non pu\uf2 fare il male volontariamente \ue8 che non conosce la differenza tra bene e male, e dunque per la stessa ragione non pu\uf2 fare volontariamente nemmeno il bene. In secondo luogo il virtuoso non fa il male volontariamente, semplicemente perch\ue9 il male non lo fa mai. E qui viene in luce qual \ue8 l'unica vera differenza tra le altre tecniche e l'etica/filosofia. Un tecnico pu\uf2 volontariamente commettere errori perch\ue9 pu\uf2 all'occorrenza operare per fini diversi da quelli della sua tecnica (ad esempio, un medico pu\uf2 voler uccidere un paziente), che al momento considera pi\uf9 importanti; invece il filosofo, ossia il tecnico dell'etica, non ha questa possibilit\ue0, perch\ue9 il fine dell'etica \ue8 la realizzazione della vita buona, e fini che possano all'occorrenza essere considerati superiori a questo non ne esistono.In Hippias Minor, especially in its last part, Plato seems going to argue that those who are able to make a mistake voluntarily (for example, lying) are better, on a moral level, than those who can not do it; and therefore, contrary to the almost unanimously opinion shared in Greek culture, which the subtle and often misleading cunning of Odysseus is superior, from a moral point of view, to the simple sincerity of Achilles. Most of the critics found embarrassing to admit that Plato supported such a thesis, and therefore tried in various ways to take cover. The most used strategy is the following: since the principle according that the one who errs voluntarily is better is valid only in relation to the techniques, Plato would be trying to prove either that ethics is not a technique, or that for this technique which is the ethics the principle in question is not valid. But this is an unsustainable point of view, because it is contrary to both the letter and the meaning of the text. In the Hippias minor, as well as many other dialogues (not just youth), what Plato wants to demonstrate, in clear polemic against the traditional ethics rooted in the ethical model called epic - Homer (that, in fact, in which the moral superiority of Achilles on Odysseus was established), is that from a formal point of view ethics (and more generally philosophy, considering the practical intent that it has in Plato) is a technique exactly like the others: it is the technique, in particular, which has as purpose the production of happiness, or the good life (after all this is already implicit in the Socratic motto according to which virtue is knowledge). And since it is unthinkable a technique in which the expert does not have enough knowledge to make mistakes, it necessarily follows that the offending principle is also valid for ethics and philosophy: those who are able to do evil voluntarily are better than those who can not do it. Naturally, if from here we derive the consequence that the virtuous does both evil and good voluntarily, while the vicious, not being able to do evil, does voluntarily only good, we would have reached an absurd conclusion. But in reality the sentence in question is doubly false. In the first place the vicious does not do good voluntarily: in fact the reason why he can not do evil voluntarily is that he does not know the difference between good and evil, and therefore for the same reason he can not voluntarily do good. In the second place, the virtuous does not do evil voluntarily, simply because evil never does it. And here is what is the only real difference between other techniques and ethics/philosophy. A technician can voluntarily make mistakes because he can, if necessary, operate for purposes other than those of his technique (for example, a doctor may want to kill a patient), which at the moment considers more important; instead the philosopher, that is the technician of the ethics, does not have this possibility, because the goal of the ethics is the realization of the good life, and goals that can be considered superior to this if they do not exist

Enzymatic Hydrolysis of Bacterial Cellulose for the Production of Nanocrystals for the Food Packaging Industry

Bacterial cellulose nanocrystals (BCNCs) obtained by enzymatic hydrolysis have been loaded in pullulan biopolymer for use as nanoparticles in the generation of high-oxygen barrier coatings intended for food packaging applications. Bacterial cellulose (BC) produced by Komagataeibacter sucrofermentans was hydrolyzed by two different enzymatic treatments, i.e., using endo-1,4-\u3b2-glucanases (EGs) from Thermobifida halotolerans and cellulase from Trichoderma reesei. The hydrolytic activity was compared by means of turbidity experiments over a period of 145 h, whereas BCNCs in their final state were compared, in terms of size and morphology, by atomic force microscopy (AFM) and dynamic light scattering (DLS). Though both treatments led to particles of similar size, a greater amount of nano-sized particles ( 48250 nm) were observed in the system that also included cellulase enzymes. Unexpectedly, transmission electron microscopy (TEM) revealed that cellulose nanoparticles were round-shaped and made of 4-5 short (150-180 nm) piled whiskers. Pullulan/BCNCs nanocomposite coatings allowed an increase in the overall oxygen barrier performance, of more than two and one orders of magnitude ( 480.7 mL\ub7m-2\ub724 h-1), of pure polyethylene terephthalate (PET) ( 48120 mL\ub7m-2\ub724 h-1) as well as pullulan/coated PET ( 486 mL\ub7m-2\ub724 h-1), with no significant difference between treatments (hydrolysis mediated by EGs or with the addition of cellulase). BCNCs obtained by enzymatic hydrolysis have the potential to generate high oxygen barrier coatings for the food packaging industry

Attosecond spectroscopy of bio-chemically relevant molecules

Understanding the role of the electron dynamics in the photochemistry of bio-chemically relevant molecules is key to getting access to the fundamental physical processes leading to damage, mutation and, more generally, to the alteration of the final biological functions. Sudden ionization of a large molecule has been proven to activate a sub-femtosecond charge flow throughout the molecular backbone, purely guided by electronic coherences, which could ultimately affect the photochemical response of the molecule at later times. We can follow this ultrafast charge flow in real time by exploiting the extreme time resolution provided by attosecond light sources. In this work recent advances in attosecond molecular physics are presented with particular focus on the investigation of bio-relevant molecules

Sterol metabolism modulates susceptibility to HIV-1 Infection

Background: 25-hydroxylase (CH25H) is an Interferon stimulated gene (ISG), which catalyzes the synthesis of 25-Hydroxycholesterol (25HC). 25HC intervenes in metabolic and infectious processes as controls cholesterol homeostasis and influences viral entry into host cells.We verified whether natural resistance to HIV-1 infection in HIV-1-exposed seronegative (HESN) individuals is at least partially mediated by particularities in sterol biosynthesis. Methods: Peripheral blood mononuclear cells (PBMCs) and monocyte-derived macrophages (MDMs) isolated from 15 sexually-exposed HESN and 15 healthy controls (HC) were in vitro HIV-1-infected and analyzed for: 1) percentage of IFN\u3b1-producing plasmacytoid Dendritic Cells (pDCs); 2) Cholesterol signaling and inflammatory response RNA expression; 3) resistance to HIV-1 infection. MDMs from 5 HC were in vitro HIV-1-infected in the absence/presence of exogenously added 25HC. Results: IFN\u3b1-producing pDCs were augmented in HESN compared to HCs both in unstimulated and in in vitro HIV-1-infected PBMCs (p<0.001). An increased expression of CH25H and of a number of genes involved in cholesterol metabolism (ABCA1, ABCG1, CYP7B1, LXR\u3b1, OSBP, PPAR\u3b3, SCARB1) was observed as well; this, was associated with a reduced susceptibility to in vitro HIV-1-infection of PBMCs and MDMs (p<0.01). Notably, addition of 25HC to MDMs resulted in increased cholesterol efflux and augmented resistance to in vitro HIV-1-infection. Conclusions: Results herein show that in HESN sterol metabolism might be particularly efficient. This could be related to the activation of the IFN\u3b1 pathway and results into a reduced susceptibility to in vitro HIV-1 infection. These results suggest a possible basis for therapeutic interventions to modulate HIV-1 infection