On Proclus as a Platonic Exegete

A response to John Finamore, “The Divided Line and the Cave in Proclus' Republic Commentary.

The Deficiencies of the Presocratic Material Elements and the Dream Theory in Theaetetus

The Dream Theory in Theaetetus is Plato's generalised account of Presocratic elements. Evidence for this given from Laws, Phaedo, Timaeus, and through a comparison with Aristotle's account

Geometrical First Principles in Proclus’ Commentary on the First Book of Euclid’s Elements

In his commentary on Euclid, Proclus says both that the first principle of geometry are self-evident and that they are hypotheses received from the single, highest, unhypo- thetical science, which is probably dialectic. The implication of this seems to be that a geometer both does and does not know geometrical truths. This dilemma only exists if we assume that Proclus follows Aristotle in his understanding of these terms. This paper shows that this is not the case, and explains what Proclus himself means by definition, hypothesis, axiom, postulate, and the self-evident, and how geometry is a science that receives its principles from dialectic

Non enim ab hiis que sensus est iudicare sensum. Sensation and Thought in Theaetetus, Plotinus and Proclus

I examine the relation between sensation and discursive thought (dianoia) in Plato, Plotinus, and Proclus. In Theaetetus, a soul whose highest faculty was sensation would have no unified experience of the sensible world, lacking universal ideas to give order to the sensible flux. It is implied that such universals are grasped by the soul’s thinking. In Plotinus the soul is not passive when it senses the world, but as the logos of all things it thinks the world through its own forms. Proclus argues against the derivation of universal logoi from the senses, which alone can’t make the sensible world comprehensible. At most they give a record of the original sense-impression in its particularity. The soul’s own projected logoi give the sensible world stability. For Proclus, bare sensation does not depend on thought, but a unified experience of the sense-world depends on its paradigmatic logoi in our souls

The Role of the Digression on the Man of the Law Courts and the Philosopher (172b-177c) in the Argument of Theaetetus

Interpretations of the Theaetetus digression fail to see how it functions in Plato’s argument because they have taken its praise of the philosopher at face value. But this is not the philosopher from Republic. His otherworldliness reflects both Theodorus’ mathematical understanding of philosophy as the study of ‘divine’ objects and the judgement of the man of the law courts that philosophy renders a man useless for the city’s business. In spite of how appealing interpreters have found it, Socrates’ mythological language shows that the philosopher is an enigma to the practical man. That is why Socrates must appeal to the practical knowledge of the crafts to refute the relativism of opinion that he had to put forward in Protagoras’ defence

The Soul and the Virtues in Proclus’ Commentary on the Republic of Plato

Dans la septième dissertation de son Commentaire sur la République de Platon, Proclus fournit les éléments d’une philosophie politique néoplatonicienne très structurée. Fidèle, de façon générale, à la description platonicienne de l’âme tripartite et des quatre vertus cardinales, il introduit cependant d’importantes nuances dans cette théorie. L’idée de la prédominance d’une partie de l’âme sur une autre et l’idée de « vies mixtes » où deux parties de l’âme prédominent en même temps élargissent la description platonicienne des différents types poli­tiques. En outre, en s’efforçant de donner diverses explications métaphysiques de la nature et du nombre des parties de l’âme et des vertus, Proclus inscrit la philosophie politique platonicienne plus ou moins tout d’une pièce dans une hiérarchie cosmique néoplatonicienne.In the 7th essay of his Commentary on the Republic of Plato, Proclus sup­plies the elements of a fairly robust Neoplatonic political philosophy. In general he agrees with Plato’s account of the tripartite soul and the four cardinal virtues, while introducing important nuances into the theory. The idea of the dominance of one part of the soul over another, and the idea of ‘mixed lives’, where two parts dominate at once, extend Plato’s account of the various political types. Further, in his attempt to give various metaphysical explanations for the nature and number of the parts of the soul and the virtues, Proclus inserts Platonic political philosophy more or less whole-cloth into a Neoplatonic cosmic hierarch

Neoplatonism and the Hegelianism of James Doull

In this study I will show how Neoplatonism is not properly understood as a moment within the Hegelian dialectic. The Hegelian analysis obscures both the true character of the Neoplatonic One, and the Neoplatonic account of the relation between thought and its object, because it treats these positions as deficient versions of itself. We must remember that the Neoplatonists had before them the long tradition of Aristotelianism and Middle Platonism, in which the first principle was a self-consciousness. They did not elevate the One beyond Nous simply because of the precedence of Plato's Parmenides; rather they interpreted that text from what they considered to be philosophical necessity. They thought that it was philosophically superior to conceive of the First as One rather than Nous/Being. And just as in Hegel, I think, the decision of this school as a whole to write of the First in this manner has its origin in their analysis of human consciousness

The Soul and Discursive Reason in the Philosophy of Proclus

In Proclus dianoia is the Soul's thinking activity, through which it makes itself into a divided image of Nous. Dianoia's thoughts are logoi, because in the Greek philosophical tradition, logos came to mean a division of a prior unity (ch.I). Proclus' theory of dianoia rejects induction, and is a conscious development of Plato's theory of anamnêsis, because induction is unable to yield a true universal (ch.II). The source of Soul's logoi is not a pre-natal vision of reality, but rather its ontological dependence on Nous. The Soul's ousia is a fullness of logoi which are images of the eidê in Nous. The Soul projects these multiple oudiôdeis logoi into even greater multiplicity. In so doing, Soul makes itself into the image of Nous, and the paradigm of Body. For this reason all dianoia is metaphorical, because it either understands Nous through the image which itself is, or understands Body through itself as paradigm (ch.III). Dianoia, therefore, has two parts. Dialectic is the Soul's grasp of Nous through itself as image, and mathematics is the Soul's grasp of Body through itself as paradigm (ch.IV). The Soul's attention to Body may cause it to cease its dianoetic activity, because it takes on Body's passivity. Philosophical discussion may rescue such a fallen soul, turning it back towards itself, away from the body. In Procline terms, philosophy restores the Soul's autokinêsis, or self-motion (ch.V). The particular Nous of which Soul is an image, and which dianoia divides, is the Nous which serves as a measure for Soul's dividing activity. And because Time is the measure of the Soul's motion, this particular Nous is the monad of Time (ch.VI). Dianoia has as its aim to leave behind all divided thinking, and to be content with the unity of Nous, and the simplicity of the One. This is accomplished through that in the Soul which is higher than dianoia, the nous of the Soul, and its own one (ch.VII)

Drivers of future alien species impacts: an expert‐based assessment

Understanding the likely future impacts of biological invasions is crucial yet highly challenging given the multiple relevant environmental, socio‐economic and societal contexts and drivers. In the absence of quantitative models, methods based on expert knowledge are the best option for assessing future invasion trajectories. Here, we present an expert assessment of the drivers of potential alien species impacts under contrasting scenarios and socioecological contexts through the mid‐21st century. Based on responses from 36 experts in biological invasions, moderate (20%–30%) increases in invasions, compared to the current conditions, are expected to cause major impacts on biodiversity in most socioecological contexts. Three main drivers of biological invasions—transport, climate change and socio‐economic change—were predicted to significantly affect future impacts of alien species on biodiversity even under a best‐case scenario. Other drivers (e.g. human demography and migration in tropical and subtropical regions) were also of high importance in specific global contexts (e.g. for individual taxonomic groups or biomes). We show that some best‐case scenarios can substantially reduce potential future impacts of biological invasions. However, rapid and comprehensive actions are necessary to use this potential and achieve the goals of the Post‐2020 Framework of the Convention on Biological Diversity

SOX2 Co-Occupies Distal Enhancer Elements with Distinct POU Factors in ESCs and NPCs to Specify Cell State

SOX2 is a master regulator of both pluripotent embryonic stem cells (ESCs) and multipotent neural progenitor cells (NPCs); however, we currently lack a detailed understanding of how SOX2 controls these distinct stem cell populations. Here we show by genome-wide analysis that, while SOX2 bound to a distinct set of gene promoters in ESCs and NPCs, the majority of regions coincided with unique distal enhancer elements, important cis-acting regulators of tissue-specific gene expression programs. Notably, SOX2 bound the same consensus DNA motif in both cell types, suggesting that additional factors contribute to target specificity. We found that, similar to its association with OCT4 (Pou5f1) in ESCs, the related POU family member BRN2 (Pou3f2) co-occupied a large set of putative distal enhancers with SOX2 in NPCs. Forced expression of BRN2 in ESCs led to functional recruitment of SOX2 to a subset of NPC-specific targets and to precocious differentiation toward a neural-like state. Further analysis of the bound sequences revealed differences in the distances of SOX and POU peaks in the two cell types and identified motifs for additional transcription factors. Together, these data suggest that SOX2 controls a larger network of genes than previously anticipated through binding of distal enhancers and that transitions in POU partner factors may control tissue-specific transcriptional programs. Our findings have important implications for understanding lineage specification and somatic cell reprogramming, where SOX2, OCT4, and BRN2 have been shown to be key factors