40,222 research outputs found
In What Sense Is the Early Universe Fine-Tuned?
It is commonplace in discussions of modern cosmology to assert that the early
universe began in a special state. Conventionally, cosmologists characterize
this fine-tuning in terms of the horizon and flatness problems. I argue that
the fine-tuning is real, but these problems aren't the best way to think about
it: causal disconnection of separated regions isn't the real problem, and
flatness isn't a problem at all. Fine-tuning is better understood in terms of a
measure on the space of trajectories: given reasonable conditions in the late
universe, the fraction of cosmological histories that were smooth at early
times is incredibly tiny. This discussion helps clarify what is required by a
complete theory of cosmological initial conditions.Comment: 28 pages. Prepared for a volume of essays commemorating David
Albert's Time and Chance, B. Loewer, E. Winsberg and B. Weslake, ed
Why Boltzmann Brains Are Bad
Some modern cosmological models predict the appearance of Boltzmann Brains: observers who randomly fluctuate out of a thermal bath rather than naturally evolving from a low-entropy Big Bang. A theory in which most observers are of the Boltzmann Brain type is generally thought to be unacceptable, although opinions differ. I argue that such theories are indeed unacceptable: the real problem is with fluctuations into observers who are locally identical to ordinary observers, and their existence cannot be swept under the rug by a choice of probability distributions over observers. The issue is not that the existence of such observers is ruled out by data, but that the theories that predict them are cognitively unstable: they cannot simultaneously be true and justifiably believed
Beyond Falsifiability: Normal Science in a Multiverse
Cosmological models that invoke a multiverse - a collection of unobservable regions of space where conditions are very different from the region around us - are controversial, on the grounds that unobservable phenomena shouldn't play a crucial role in legitimate scientific theories. I argue that the way we evaluate multiverse models is precisely the same as the way we evaluate any other models, on the basis of abduction, Bayesian inference, and empirical success. There is no scientifically respectable way to do cosmology without taking into account different possibilities for what the universe might be like outside our horizon. Multiverse theories are utterly conventionally scientific, even if evaluating them can be difficult in practice
Why is the Universe Accelerating?
The universe appears to be accelerating, but the reason why is a complete
mystery. The simplest explanation, a small vacuum energy (cosmological
constant), raises three difficult issues: why the vacuum energy is so small,
why it is not quite zero, and why it is comparable to the matter density today.
I discuss these mysteries, some of their possible resolutions, and some issues
confronting future observations.Comment: 22 pages; Contribution to Measuring and Modeling the Universe,
Carnegie Observatories Astrophysics Series Vol. 2, ed. W. L. Freedman;
references improve
Why Is There Something, Rather Than Nothing?
It seems natural to ask why the universe exists at all. Modern physics suggests that the universe can exist all by itself as a self-contained system, without anything external to create or sustain it. But there might not be an absolute answer to why it exists. I argue that any attempt to account for the existence of something rather than nothing must ultimately bottom out in a set of brute facts; the universe simply is, without ultimate cause or explanation
The structural contradictions and constraints on corporate social responsibility: Challenges for corporate social irresponsibility
Purpose - This chapter engages critically with the ideas of corporate social responsibility (CSR) and irresponsibility (CSI) in order to examine their utility for the purposes of realizing more socially just and environmentally sustainable social and economic practices. Methodology/approach - The chapter develops Marx's understanding of the twin pressures of class struggle and inter-capitalist competition in setting the limits of agency for corporate actors. It is thus theoretical and discursive in nature. Findings - The findings of the chapter suggest that the scope for corporate agency in relation to responsibility/irresponsibility is severely limited by inter-capitalist competition and capitalist social relations. It therefore argues that those interested in social justice and environmental sustainability should focus on these structural pressures rather than theorizing corporate agency. Social implications - The research suggests that the focus of academic and government attention should be on resolving the contradictions and exploitative social relations inherent in capitalism. Without this emphasis activism, corporate agency and government action will not eradicate the types of problem that advocates of CSR/CSI are concerned about. Originality/value of paper - The value of the paper is that it contests and engages critically with the utility of the notion of CSR and the emergent concept of CSI. It asks proponents of these concepts to think seriously about the structural pressures and constraints within which business and policy makers act. Copyrightr © 2012 by Emerald Group Publishing Limited
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