The Dioptrique

Author(s):  
Walter Ott

Descartes’s treatment of perception in the Optics, though published before the Meditations, contains a distinct account of sensory experience. The end of the chapter suggests some reasons for this oddity, but that the two accounts are distinct is difficult to deny. Descartes in the present work topples the brain image from its throne. In its place, we have two mechanisms, one purely causal, the other inferential. Where the proper sensibles are concerned, the ordination of nature suffices to explain why a given sensation is triggered on the occasion of a given brain motion. The same is true with regard to the common sensibles. But on top of this purely causal story, Descartes re-introduces his doctrine of natural geometry.

2008 ◽  
Vol 24 (3) ◽  
pp. 419-429 ◽  
Author(s):  
Anthony Landreth ◽  
John Bickle

We briefly describe ways in which neuroeconomics has made contributions to its contributing disciplines, especially neuroscience, and a specific way in which it could make future contributions to both. The contributions of a scientific research programme can be categorized in terms of (1) description and classification of phenomena, (2) the discovery of causal relationships among those phenomena, and (3) the development of tools to facilitate (1) and (2). We consider ways in which neuroeconomics has advanced neuroscience and economics along each line. Then, focusing on electrophysiological methods, we consider a puzzle within neuroeconomics whose solution we believe could facilitate contributions to both neuroscience and economics, in line with category (2). This puzzle concerns how the brain assigns reward values to otherwise incomparable stimuli. According to the common currency hypothesis, dopamine release is a component of a neural mechanism that solves comparability problems. We review two versions of the common currency hypothesis, one proposed by Read Montague and colleagues, the other by William Newsome and colleagues, and fit these hypotheses into considerations of rational choice.


Author(s):  
Walter Ott

This chapter examines the crisis of perception as it figures in the work of four of Descartes’s immediate successors: Louis de la Forge, Robert Desgabets, Pierre-Sylvain Régis, and Antoine Arnauld. La Forge opts for a version of Descartes’s last view, which has no place for natural geometry. Desgabets defends a version of Descartes’s earliest view, which requires the mind to turn to the brain image. Régis thinks we sense colors and sounds and the rest and then use these to imagine extension. Arnauld’s case is especially problematic, since he rejects the mind-independent existence of sensible qualities but seems committed to some version of direct realism. He is then left with the question how the mind projects these illusory states on to extended bodies, a question for which he has no answer.


Author(s):  
Walter Ott

Descartes’s earliest theory of perception attempts to marry the remnants of the Baconian and Aristotelian views while divorcing them from hylomorphism and the innocent view of sensible qualities. Descartes holds the ‘overlap thesis,’ the claim that any behavior exhibited by non-human animals and inattentive humans must receive the same explanation. Corporeal perception requires the presence of a brain image that resembles its object. When the mind attends to its environment, it is immediately aware of this brain image and, through it, of the common sensibles. The claim that the mind ‘turns toward’ the brain is a thoroughly traditional one. The proper sensibles are summoned by the mind on the occasion of its undergoing certain brain events. Descartes thinks of the mind as ‘decoding’ the language of the brain in order to provide itself with the appropriate sensations. But those sensations do nothing to explain our awareness of objects.


Author(s):  
Michio Sugeno ◽  
◽  
Takahiro Yamanoi ◽  

This paper discusses brain activity during the understanding of sentences from the perspective of Systemic Functional Linguistics. We focus on ideational meaning (propositional meaning in an ordinary sense) and interpersonal meaning (as is typically seen in honorific expressions). The present study is an experimental exploration of the spatiotemporal pathways of neuronal activation. Japanese sentences containing and not containing honorific expressions are compared in electroencephalography experiments. In these experiments, the sentences without honorific expressions have ideationalmeaning, but those with honorific expressions have both ideational and interpersonal meanings. Through the use of the equivalent current dipole source localization method, the spatiotemporal processes of activation of the brain are analyzed. There is a single pathway during the understanding of the sentences without honorific expressions; this pathway is mainly observed in the left hemisphere. On the other hand, there are three pathways in the case of the sentences with honorific expressions, two of which are observed in the right hemisphere. The remaining pathway is the same as the aforementioned single pathway. This fact strongly suggests that the common pathway is concerned with processing ideational meaning. The other two pathways observed during understanding of the sentences with honorific expressions are considered to be related to processing interpersonal meaning.


Author(s):  
Walter Ott

This chapter sets out the predicament in which Descartes finds himself at the start of his career. The crisis of perception is a result of the collapse of two positions. First is the naïve or innocent view, which held sway since the time of Aristotle. On this view, bodies really do have the qualities they appear to; what is more, it is by perceiving the qualities proper to each sense (as color is proper to sight, for instance) that we perceive the size, shape, and motion of bodies. The innocent view was paired with an empirical theory known as ‘the Baconian synthesis.’ This view posits species that progress from the eye inward to the ventricles of the brain, where they are assimilated in the ‘common’ sense and assembled into a complete sensory experience of the objects of perception. The demise of both views opens the field for Descartes’s own theory.


2018 ◽  
Vol 46 (1) ◽  
pp. 6
Author(s):  
Letícia Menezes Freitas ◽  
Kleber Fernando Pereira ◽  
Fabiano Rodrigues De Melo ◽  
Leandro Silveira ◽  
Odeony Paulo Dos Santos ◽  
...  

Background: The pacarana lives in South America and has herbivorous and nocturnal habits. It is a rare species with scarce data concerning its morphology and adding more data is important in establishing its vulnerability. The aim was to describe its macroscopic brain anatomy, as well as the brain vascularization.Materials, Methods & Results: Two specimens were available for this study, that were donated post-mortem. The animals were injected with latex and fixed with 10% formaldehyde. Upon exposure and removal of the brain its main features were described. The rhinal fissure is single and the lateral sulcus arises from its caudal part. There are two sagittal sulci, an extensive medial sulcus and a short lateral sulcus. The piriform lobe is vermiform and the rostral part is smaller. The caudal colliculus is larger than the rostral colliculus and they are separated by a sulcus. The cerebellum has oval shape and the flocculus lobe is not conspicuous. The cerebral arterial circle was analyzed and described. The brain is supplied by the vertebrobasilar system only. The cerebral arterial circle is formed by the terminal branch of the basilar artery, the caudal communicating artery, the rostral cerebral artery and the rostral communicating artery. The caudal and middle cerebellar arteries are branches of the basilar artery. The terminal branch of the basilar artery originates the rostral cerebellar artery and the caudal cerebral artery. From the end of the caudal communicating artery and the beginning of the rostral cerebral artery arises the middle cerebral artery.Discussion: The cerebral structures related to sensory inputs reflect the species usage of senses, or rather one is intrinsically correlated to the other. The caudal colliculus is larger than the rostral colliculus, as the former is related to hearing and the latter to the vision, this indicates that the visual sense is not so important. Indeed, the animals are nocturnal and have small eyes. The hearing on the other hand is used in social interactions, to indicate combat, threat and defensive situations, for example. The rhinencephalon has the most conspicuous external sensory structures and the animals use olfaction for social behaviors, even producing a gland exudate to mark territory. Most brain features are similar with other species in the infraorder Caviomorpha. The brain of the pacarana resembles the brains of the Patagonian mara, capybara and guinea pig. The common porcupine presents a different shape to the brain. The guinea pig and the common porcupine are lissencephalic. The animals that present sulci in the brain, follow this order from more to less girencephalic: capybara, mara and pacarana. The rhinal fissure is important because it delimits the rhinencephalon and it is present in all the animals mentioned above. In the mara, the colliculi are exposed in dorsal and lateral views, however, this does not happen for the pacarana. The cerebellum is similar in these species, but the flocculus is more pronounced in the guinea pig. The brain of Caviomorpha species is supplied only by the vertebrobasilar system in most species analyzed, as in the capybara, guinea pig, coypus, mara, chinchilla, degu and in pacarana, where the absence of the carotid artery was observed. In some species the rostral cerebral artery anastomosis in a single branch that runs towards the corpus callosum (degu, capybara, chinchilla and coypus), but in the pacarana the rostral cerebral artery is present in both left and right sides, then branching towards the corpus callosum and the splenial sulcus. In summary, the pacarana presents brain features similar to other Caviomorpha, with some specific species variation.


Mr. Brodie was induced to draw up the account of this case, although other instances are already recorded, because the child differed much less from the natural formation than usual. Twins were produced, both still-born, at the seventh month of pregnancy. The placenta was not preserved; but it was remarked that the chords belonging to the two children were, at their attachment, distant about three inches from each other. In one of these children nothing preternatural was observed. The other was distended, and disfigured with fluid contained in two cysts under the common integuments of the neck and thorax; but when the fluid was evacuated, the form was nearly natural, with the exception of a hare lip, and a deficiency of some of the toes and fingers. In the brain also, and nervous system, nothing unusual was observed. But in the thorax there was no heart, thymus gland, or pleura; and the substances corresponding to lungs, on each side, at the bifurcation of the trachea, were no more than one third of an inch in diameter, the thorax being filled with a dense cellular substance.


Author(s):  
William P. Wergin ◽  
Eric F. Erbe

The eye-brain complex allows those of us with normal vision to perceive and evaluate our surroundings in three-dimensions (3-D). The principle factor that makes this possible is parallax - the horizontal displacement of objects that results from the independent views that the left and right eyes detect and simultaneously transmit to the brain for superimposition. The common SEM micrograph is a 2-D representation of a 3-D specimen. Depriving the brain of the 3-D view can lead to erroneous conclusions about the relative sizes, positions and convergence of structures within a specimen. In addition, Walter has suggested that the stereo image contains information equivalent to a two-fold increase in magnification over that found in a 2-D image. Because of these factors, stereo pair analysis should be routinely employed when studying specimens.Imaging complementary faces of a fractured specimen is a second method by which the topography of a specimen can be more accurately evaluated.


1968 ◽  
Vol 59 (3) ◽  
pp. 479-486 ◽  
Author(s):  
Lars-Ake Idahl ◽  
Bo Hellman

ABSTRACT The combination of enzymatic cycling and fluorometry was used for measuring glucose and glucose-6-phosphate in pancreatic β-cells from obese-hyperglycaemic mice. The glucose level of the β-cells corresponded to that of serum over a wide concentration range. In the exocrine pancreas, on the other hand, a significant barrier to glucose diffusion across the cell membranes was demonstrated. During 5 min of ischaemia, the glucose level remained practically unchanged in the β-cells while it increased in the liver and decreased in the brain. The observation that the pancreatic β-cells are characterized by a relatively low ratio of glucose-6-phosphate to glucose may be attributed to the presence of a specific glucose-6-phosphatase.


Author(s):  
Mauro Rocha Baptista

Neste artigo analisamos a relação do Ensino Religioso com a sua evolução ao longo do contexto recente do Brasil para compreender a posição do Supremo Tribunal Federal ao considerar a possibilidade do Ensino Religioso confessional. Inicialmente apresentaremos a perspectiva legislativa criada com a constituição de 1988 e seus desdobramentos nas indicações curriculares. Neste contexto é frisado a intenção de incluir o Ensino Religioso na Base Nacional Curricular Comum, o que acabou não acontecendo. A tendência manifesta nas duas primeiras versões da BNCC era de um Ensino Religioso não-confessional. Uma tendência que demarcava a função do Ensino Religioso em debater a religião, mas que não permitia o direcionamento por uma vertente religioso qualquer. Esta posição se mostrava uma evolução da primeira perspectiva histórica mais associada à catequese confessional. Assim como também ultrapassava a interpretação posterior de um ecumenismo interconfessional, que mantinha a superioridade do cristianismo ante as demais religiões. Sendo assim, neste artigo, adotaremos o argumento de que a decisão do STF, de seis votos contra cinco, acaba retrocedendo ante o que nos parecia um caminho muito mais frutífero.Palavras-chave: Ensino Religioso. Supremo Tribunal Federal. Confessional. Interconfessional. Não-confessional.Abstract: On this article, we analyze the relation between Religious education and its evolution along the currently Brazilian context in order to understand the position of the Supreme Court in considering the possibility of a confessional Religious education. Firstly, we are going to present the legislative perspective created with the 1988 Federal Constitution and its impacts in the curricular lines. On this context it was highlighted the intention to include the Religious Education on the Common Core National Curriculum (CCNC), which did not really happened. The tendency manifested in the first two versions of the CCNC was of a non-confessional Religious Education. A tendency that delineated the function of the Religious Education as debating religion, but not giving direction on any religious side. This position was an evolution of the first historical perspective more associated to the confessional catechesis. It also went beyond the former interpretation of an inter-confessional ecumenism, which kept the superiority of the Christianity over the other religions. As such, in this paper we adopt the argument that the decision of the Supreme Court, of six votes against five, is a reversal of what seemed to be a much more productive path on the Religious Education.Keywords: Religious Education. Brazilian Supreme Court. Confessional. Inter-confessional. Non- confessional.Enviado: 23-01-2018 - Aprovado e publicado: 12-2018


Sign in / Sign up

Export Citation Format

Share Document