The Hard Problem for Soft Moral Realism

Several leading moral philosophers have recently proposed a soft version of moral realism, according to which moral facts—though it is reasonable to postulate them—cannot metaphysically explain other facts (Dworkin 2011; Parfit 2011; Scanlon 2014). However, soft moral realism is faced with what I call the “Hard Problem”, namely, the problem of how this soft version of moral metaphysics could accommodate moral knowledge. This paper reconstructs three approaches to solving the Hard Problem on behalf of the soft realist: the autonomy approach, the intuitionist approach, and the third-factor approach. I then argue that none of them is successful

Unitarity Quadrangles of Four Neutrino Mixing

We present a classification of the unitarity quadrangles in the four-neutrino mixing scheme. We find that there are totally thirty-six distinct topologies among twelve different unitarity quadrangles. Concise relations are established between the areas of those unitarity quadrangles and the rephasing invariants of CP and $T$ violation.Comment: RevTex 10 pages. Minor changes made. Accepted for publication in Phys. Rev.

Portfolio Analysis and Zero-Beta CAPM with Heterogeneous Beliefs

With the standard mean variance framework, by assuming heterogeneity and bounded rationality of investors, this paper examines their impact on the market equilibrium and implications to the portfolio analysis. By constructing a market consensus belief, we establish market equilibrium prices of risky assets and show that the standard Black’s zero-beta CAPM under homogeneous beliefs holds under the heterogeneous belief. We demonstrate that the biased belief (from the market consensus belief) of investors makes their optimal portfolio not necessarily locate on the market mean-variance frontier. We show that the traditional geometric relation of the mean variance frontiers with and without the riskless asset under the homogeneous beliefs does not hold under the heterogeneous beliefs. The results shed light on the risk premium puzzle, Miller’s hypothesis, the lower market performance when the access to the riskfree asset is impossible, and the empirical finding that managed funds under-perform comparing to the market indices on average.asset prices; heterogeneous beliefs; portfolio analysis; zero-beta CAPM

Heterogeneity, Bounded Rationality and Market Dysfunctionality

As the main building blocks of the modern finance theory, homogeneity and rational expectation have faced difficulty in explaining many market anomalies, stylized factors, and market inefficiency in empirical studies. As a result, heterogeneity and bounded rationality have been used as an alterative paradigm of asset price dynamics and this paradigm has been widely recognized recently in both academic and financial market practitioners. Within the framework of Chiarella, Dieci and He (2006a, 2006b) on mean-variance analysis under heterogeneous beliefs in terms of either the payoffs or returns of the risky assets, this paper examines the effect of the heterogeneity. We first demonstrate that, in market equilibrium, the standard one fund theorem under homogeneous belief does not held under heterogeneous belief in general, however, the optimal portfolios of investors are very close to the market efficient frontier. By imposing certain distribution assumption on the heterogeneous beliefs, we then use Monte Carlo simulations to show that certain heterogeneity among investors can improve the Sharpe and Treynor ratios of the portfolios and investors can benefit from the diversity in investors’ beliefs. We also show that non-normality of market equilibrium return distributions is an outcome of the market aggregation of individual investors who make rational decisions based on their beliefs. Our results explain the empirical funding that that managed funds under-perform the market index on average and show that heterogeneity can improve the market efficiency.heterogeneity; bounded rationality; heterogeneous CAPM; mean-variance efficiency; Sharpe and Treynor ratios

Differences in Opinion and Risk Premium

When people agree to disagree, this paper examines the impact of the disagreement among agents on market equilibrium and equity premium. Within the standard mean variance framework, we consider a market of two risky assets, a riskless asset and two (and then a continuum of) agents who have different preferences and heterogeneous beliefs in the means and variance/covariances of the asset returns. By constructing a consensus belief, we introduce a boundedly rational equilibrium (BRE) to characterize the market equilibrium and derive a CAPM under heterogeneous beliefs. When the differences in opinion are formed as mean-preserving spreads of a benchmark homogeneous belief, we analyz eexplicitly the impact on the market equilibrium and risk premium, showing that the risk tolerance, optimism/pessimism and con?dence/doubt can jointly generate high risk premium and low risk-free rate. JELClassi?cation:.Assetprices;heterogeneousbeliefs;boundedlyrationalequilibriuasset prices; heterogeneous beliefs; boundedly rational equilibrium; zero-beta CAPM; risk premium

Roles of Neurotransmitters in the Regulation of Neuronal Electrical Properties and Growth Cone Motility

In addition to acting in synaptic transmission, neurotransmitters have been shown to play roles in the development of nervous system. Developing neurons extend neurites to connect to their target cells, and growth cones at the tip of growing neurites are critical for pathfinding. Although evidence for the regulation of axonal growth and growth cone guidance by neurotransmitters and neuromodulators is emerging, less is known about the mechanisms by which neurotransmitters affect developing neurons. Here, I focus on three neurotransmitters/ neuromodulators and describe their actions (a) at the level of growth cone, especially on filopodia, which serve as sensors that allow growth cones to probe the environment they are traversing, and (b) on how neurotransmitters modulate neuronal electrical properties, which, in itself, have been shown to affect neurite extension. The goals of this dissertation are to investigate 1) the cholinergic modulation of neuronal activity and its effects on growth cone motility; 2) the excitatory modulation of neuronal excitability by nitric oxide (NO); and 3) the inhibitory modulation of neuronal activity by dopamine (DA). The work uses a well-established model system to investigate growth cone motility and neuronal activity: identified neurons from the pond snail Helisoma trivolvis studied in cell culture or in the intact ganglion in situ. The study of B5 neurons demonstrates that acetylcholine (ACh) induces filopodial elongation, which is mediated by opening of nicotinic ACh receptors, membrane depolarization, and elevation of intracellular Ca level in growth cones. This dissertation also shows that NO inhibits two types of Ca-activated K channels to depolarize the membrane potential of B19 neurons. Additionally, the study reveals that DA serves as an inhibitory neurotransmitter to hyperpolarize and silence the electrical activity of firing B5 neurons via a D2-like receptor/PLC/K channel pathway. Taken together, this dissertation elucidates novel cellular mechanisms through which neurotransmitters can regulate growth cone motility and neuronal electrical properties, further supporting evidence for potential roles of neurotransmitters in axon pathfinding and synaptic transmission in vivo