Love and Friendship in the Lysis and the Symposium: Human and Divine

The paper claims that we cannot understand properly Platonic conception of love and friendship unless we read the Lysis in the light of the Symposium and vice verse. Dealing with the crucial question of what made Plato write two different dialogues on the same topic, it advocates an alternative intertextual reading that does not deny progress of Plato’s thinking. Though the Symposium offers, in comparison to the Lysis, a more developed philosophical theory of love, Plato still has good reasons to articulate the dilemmas presented in the Lysis. Combining the contrast in dialogue endings with the similarity in structure and in argumentation, Plato makes clear that, between the Lysis and the Symposium, there is progress and constancy at the same time: while the Symposium gives a philosophical account of what we can call “divine love”, it accepts and even emphasizes the insight of the Lysis that philosophical love can imply lack of what we usually consider worth loving. Plato in the Symposium does not discard “human love” and does not conceal possible troubles of philosophical, i.e. divine love. Therefore, the critique of Plato as being champion of impersonal or “ideal” love is unpersuasive

Analogie dobra u Platóna a Aristotela

Platónovy pokusy o určení dobra lze nalézt v celém jeho díle. Zahrnují jak relativně „univoční“ koncepci dobra ve smyslu sókratovského intelektualismu, tak pluralističtější koncepci obsaženou v politickém projektu Zákonů. Podle vývojové interpretace Platónových dialogů to naznačuje posun v autorově myšlení způsobený poznáním obtížnosti problému. Byl to přitom údajně teprve Aristotelés, kdo vyřešil Platónův problém dobra pomocí pojmu analogie. Proti této interpretaci článek zdůrazňuje, že aristotelské pojetí analogie je hluboce zakořeněno v Platónově vlastním potýkání se s rozdílem mezi morálním a politickým dobrem. Byla to především Platónovo pochopení specifické hodnoty politické plurality, které stojí v základě akademického rozlišení mezi analogia a pros he

Aristotelés o panství: mezi Heideggerem a Gagarinem

Je otrok podle Aristotela vykořisťovaným nástrojem výroby stojícím na úrovni zvířete, nebo méně nadaným jedincem, jenž může svoje omezené možnosti naplnit pouze jako podřízený člen domácnosti? Aristotelští badatelé zdůrazňují jednu z možností podle toho, nakolik jsou sami liberálně, či komunitaristicky orientováni: buď je Aristotelova teorie panství vykládána jako nelidská a ideologická, nebo jako realistická a solidární. Spor se však netýká pouze „liberalismu“ a „komunitarismu“ v Aristotelovi, nýbrž – jelikož je otrok v obou výkladech chápán jako nástroj pána – také dvou základních pojetí techniky a v důsledku moderní civilizace obecně, jež jsou zastoupeny na jedné straně Lévinasovým Gagarinem a na druhé straně Heideggerem. Aristotelés naznačuje – a to pomocí technicky přesného důkazu – možnost techniky, která osvobozuje od nutnosti, přitom si je však vědom podmíněnosti každého takového osvobození. Výdobytkem Aristotelovy teorie panství je to, že se v ní hledisko rovnosti a svobody a hledisko podřízení a nutnosti nikoli vylučují, nýbrž vzájemně doplňuj

Die beste Staatsverfassung zwischen Komik und Ernst

The chapter, while exploring the interconnections between Plato’s Republic and Aristophanes’ Ecclesiazusae, postulates the existence of a third common source, which was presumably Hippodamus’ project of the best constitution. Hippodamus embraced the Pythagorean idea that the leading role in the polis should pertain to a group of morally and intellectually perfect philosophers who live on a communist basis; on this background, he proposed a tripartite functional division of the city. Aristophanes had adopted this model and reformulated it comically by identifying the ruling group with women. This comical travesty then successfully manifested the fundamental connection between nourishing, sexuality and ruling. In the Republic, Plato integrates all these impulses into the dialectical context and develops a theory of naturalness of the political community

Dynamik und Stabilität der Tugend in Platons Nomoi

Plato’s theory of virtue in the Laws could be striking for someone who is more familiar with Aristotle’s ethics for conceptual complementarity between the two positions (contrary emotions, the ordering element of reason, virtue as a mean which lies between two forms of vice, typically linked to excessive actions, etc.). Plato’s theory, however, still differs from that of Aristotle in two crutial points. First, the source of emotional dynamism is, according to Plato, supraindividual as far as the psyche is a cosmological principle. Only if it comes to be formed and ordered, it separates from the universal cosmic context and make up the emotional nature of an individual soul. But the soul is not, and this is the second point of difference, ordered by some external element (training or education, organized by a rational agent). Plato counts on a pre-arranged order of emotions at a particular ontological topos of the individual soul into which reason eventually descends. Emotions, on their part, seem to include a nexus between formable and forming that is chronologically and methodocally prior to that between the biological substratum and its rational organization, as assumed by Aristotle

Aleš Havlíček (1956-2015) in memoriam

Obituar

Substrate selectivity and catalytic activation of the type III CRISPR ancillary nuclease Can2

Type III CRISPR-Cas systems provide adaptive immunity against foreign mobile genetic elements through RNA-guided interference. Sequence-specific recognition of RNA targets by the type III effector complex triggers the generation of cyclic oligoadenylate (cOA) second messengers that activate ancillary effector proteins, thus reinforcing the host immune response. The ancillary nuclease Can2 is activated by cyclic tetra-AMP (cA4); however, the mechanisms underlying cA4-mediated activation and substrate selectivity remain elusive. Here we report crystal structures of Thermoanaerobacter brockii Can2 (TbrCan2) in substrate- and product-bound complexes. We show that TbrCan2 is a single strand-selective DNase and RNase that binds substrates via a conserved SxTTS active site motif, and reveal molecular interactions underpinning its sequence preference for CA dinucleotides. Furthermore, we identify a molecular interaction relay linking the cA4 binding site and the nuclease catalytic site to enable divalent metal cation coordination and catalytic activation. These findings provide key insights into the molecular mechanisms of Can2 nucleases in type III CRISPR-Cas immunity and may guide their technological development for nucleic acid detection applications