177 research outputs found
The evolution and development of visual perspective taking
I outline three conceptions of seeing that a creature might possess: âthe headlamp conception,â which involves an understanding of the causal connections between gazing at an object, certain mental states, and behavior; âthe stage lights conception,â which involves an understanding of the selective nature of visual attention; and seeing-as. I argue that infants and various nonhumans possess the headlamp conception. There is also evidence that chimpanzees and 3-year-old children have some grasp of seeing-as. However, due to a dearth of studies, there is no evidence that infants or nonhumans possess the stage lights conception of seeing. I outline the kinds of experiments that are needed, and what we stand to learn about the evolution and development of perspective taking
Finite temperature behaviour of the ISS-uplifted KKLT model
We study the static phase structure of the ISS-KKLT model for moduli
stabilisation and uplifting to a zero cosmological constant. Since the
supersymmetry breaking sector and the moduli sector are only gravitationally
coupled, we expect negligible quantum effects of the modulus upon the ISS
sector, and the other way around. Under this assumption, we show that the ISS
fields end up in the metastable vacua. The reason is not only that it is
thermally favoured (second order phase transition) compared to the phase
transition towards the supersymmetric vacua, but rather that the metastable
vacua form before the supersymmetric ones. This nice feature is exclusively due
to the presence of the KKLT sector. We also show that supergravity effects are
negligible around the origin of the field space. Finally, we turn to the
modulus sector and show that there is no destabilisation effect coming from the
ISS sector.Comment: 23 pages, 3 figures, mistake corrected, one plot updated, physical
conclusions unchange
Moduli stabilization and uplifting with dynamically generated F-terms
We use the F-term dynamical supersymmetry breaking models with metastable
vacua in order to uplift the vacuum energy in the KKLT moduli stabilization
scenario. The main advantage compared to earlier proposals is the manifest
supersymmetric treatment and the natural coexistence of a TeV gravitino mass
with a zero cosmological constant. We argue that it is generically difficult to
avoid anti de-Sitter supersymmetric minima, however the tunneling rate from the
metastable vacuum with zero vacuum energy towards them can be very suppressed.
We briefly comment on the properties of the induced soft terms in the
observable sector.Comment: 18 pages, no figures Comments and one reference adde
Novel colours and the content of experience
I propose a counterexample to naturalistic representational theories of phenomenal character. The counterexample is generated by experiences of novel colours reported by Crane and Piantanida. I consider various replies that a representationalist might make, including whether novel colours could be possible colours of objects and whether one can account for novel colours as one would account for binary colours or colour mixtures. I argue that none of these strategies is successful and therefore that one cannot fully explain the nature of the phenomenal character of perceptual experiences using a naturalistic conception of representation
Evidence for early life in Earthâs oldest hydrothermal vent precipitates
Although it is not known when or where life on Earth began, some of the earliest habitable environments may have been submarine-hydrothermal vents. Here we describe putative fossilized microorganisms that are at least 3,770 million and possibly 4,280 million years old in ferruginous sedimentary rocks, interpreted as seafloor-hydrothermal vent-related precipitates, from the Nuvvuagittuq belt in Quebec, Canada. These structures occur as micrometre-scale haematite tubes and filaments with morphologies and mineral assemblages similar to those of filamentous microorganisms from modern hydrothermal vent precipitates and analogous microfossils in younger rocks. The Nuvvuagittuq rocks contain isotopically light carbon in carbonate and carbonaceous material, which occurs as graphitic inclusions in diagenetic carbonate rosettes, apatite blades intergrown among carbonate rosettes and magnetiteâhaematite granules, and is associated with carbonate in direct contact with the putative microfossils. Collectively, these observations are consistent with an oxidized biomass and provide evidence for biological activity in submarine-hydrothermal environments more than 3,770 million years ago
Bayes and health care research.
Bayesâ rule shows how one might rationally change oneâs beliefs in the light of evidence. It is the foundation of a statistical method called Bayesianism. In health care research, Bayesianism has its advocates but the dominant statistical method is frequentism.
There are at least two important philosophical differences between these methods. First, Bayesianism takes a subjectivist view of probability (i.e. that probability scores are statements of subjective belief, not objective fact) whilst frequentism takes an objectivist view. Second, Bayesianism is explicitly inductive (i.e. it shows how we may induce views about the world based on partial data from it) whereas frequentism is at least compatible with non-inductive views of scientific method, particularly the critical realism of Popper.
Popper and others detail significant problems with induction. Frequentismâs apparent ability to avoid these, plus its ability to give a seemingly more scientific and objective take on probability, lies behind its philosophical appeal to health care researchers.
However, there are also significant problems with frequentism, particularly its inability to assign probability scores to single events. Popper thus proposed an alternative objectivist view of probability, called propensity theory, which he allies to a theory of corroboration; but this too has significant problems, in particular, it may not successfully avoid induction. If this is so then Bayesianism might be philosophically the strongest of the statistical approaches. The article sets out a number of its philosophical and methodological attractions. Finally, it outlines a way in which critical realism and Bayesianism might work together.
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Accidental Inflation in String Theory
We show that inflation in type IIB string theory driven by the volume modulus
can be realized in the context of the racetrack-based Kallosh-Linde model (KL)
of moduli stabilization. Inflation here arises through the volume modulus
slow-rolling down from a flat hill-top or inflection point of the scalar
potential. This situation can be quite generic in the landscape, where by
uplifting one of the two adjacent minima one can turn the barrier either to a
flat saddle point or to an inflection point supporting eternal inflation. The
resulting spectral index is tunable in the range of 0.93 < n_s < 1, and there
is only negligible production of primordial gravitational waves r < 10^{-6}.
The flatness of the potential in this scenario requires fine-tuning, which may
be justified taking into account the exponential reward by volume factors
preferring the regions of the universe with the maximal amount of slow-roll
inflation. This consideration leads to a tentative prediction of the spectral
index or depending on whether the
potential has a symmetry phi -> - phi or not.Comment: 15 pages, 6 figures, LaTeX, uses RevTex
Metastable vacua and geometric deformations
We study the geometric interpretation of metastable vacua for systems of D3
branes at non isolated toric deformable singularities. Using the L^{aba}
examples, we investigate the relations between the field theoretic susy
breaking and restoration and the complex deformations of the CY singularities.Comment: Minor corrections, references added, published in JHE
Predictive coding and representationalism
According to the predictive coding theory of cognition (PCT), brains are
predictive machines that use perception and action to minimize prediction error, i.e. the discrepancy between bottomâup, externally-generated sensory signals and topâdown, internally-generated sensory predictions. Many consider PCT to have an explanatory scope that is unparalleled in contemporary cognitive science and see in it a framework that could potentially provide us with a unified account of cognition. It
is also commonly assumed that PCT is a representational theory of sorts, in the sense that it postulates that our cognitive contact with the world is mediated by internal representations. However, the exact sense in which PCT is representational remains unclear; neither is it clear that it deserves such statusâthat is, whether it really invokes structures that are truly and nontrivially representational in nature. In the present article, I argue that the representational pretensions of PCT are completely justified. This is because the theory postulates cognitive structuresânamely action-guiding, detachable, structural models that afford representational error detectionâthat play genuinely representational functions within the cognitive system
The theory of brain-sign: a physical alternative to consciousness
Consciousness and the mind are prescientific concepts that begin with Greek theorizing. They suppose human rationality and reasoning placed in the human head by (in Christian terms) God, who structured the universe he created with the same kind of underlying characteristics. Descartes' development of the model included scientific objectivity by placing the mind outside the physical universe. In its failure under evidential scrutiny and without physical explanation, this model is destined for terminal decline. Instead, a genuine biological and physical function for the brain phenomenon can be developed. This is the theory of brain-sign. It accepts the causality of the brain as its physical characteristics, already under scientific scrutiny. What is needed is a new neurophysiological mapping language that specifies the relation of the structure and operation of the brain to organismic action in the world. Still what is lacking is an account of how neurophysiologies in different organisms communicate on dynamic, i.e. unpredictable, tasks. It is this evolved capacity that has emerged as brain-sign. Thus rather than mentality being an inner epistemological parallel world suddenly appearing in the head, brain-sign, as the neural sign of the causal status of the brain, facilitates the communicative medium of otherwise isolated organisms. The biogenesis of the phenomenon emerges directly from the account of the physical brain, and functions as a monistic feature of organisms in the physical world. This new paradigm offers disciplinary compatibility, and genuine development in behavioral and brain sciences
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