Quantum jumps,superpositions, and the continuous evolution of quantum states

The apparent dichotomy between quantum jumps on the one hand, and continuous time evolution according to wave equations on the other hand, provided a challenge to Bohr's proposal of quantum jumps in atoms. Furthermore, Schrödinger's time-dependent equation also seemed to require a modification of the explanation for the origin of line spectra due to the apparent possibility of superpositions of energy eigenstates for different energy levels. Indeed, Schrödinger himself proposed a quantum beat mechanism for the generation of discrete line spectra from superpositions of eigenstates with different energies.However, these issues between old quantum theory and Schrödinger's wave mechanics were correctly resolved only after the development and full implementation of photon quantization. The second quantized scattering matrix formalism reconciles quantum jumps with continuous time evolution through the identification of quantum jumps with transitions between different sectors of Fock space. The continuous evolution of quantum states is then recognized as a sum over continually evolving jump amplitudes between different sectors in Fock space.In today's terminology, this suggests that linear combinations of scattering matrix elements are epistemic sums over ontic states. Insights from the resolution of the dichotomy between quantum jumps and continuous time evolution therefore hold important lessons for modern research both on interpretations of quantum mechanics and on the foundations of quantum computing. They demonstrate that discussions of interpretations of quantum theory necessarily need to take into account field quantization. They also demonstrate the limitations of the role of wave equations in quantum theory, and caution us that superpositions of quantum states for the formation of qubits may be more limited than usually expected.     

Lockean superaddition and Lockean humility

This paper offers a new approach to an old debate about superaddition in Locke. Did Locke claim that some objects have powers that are unrelated to their natures or real essences? The question has split commentators. Some (Wilson, Stuart, Langton) claim the answer is yes and others (Ayers, Downing, Ott) claim the answer is no. This paper argues that both of these positions may be mistaken. I show that Locke embraced a robust epistemic humility. This epistemic humility includes ignorance of the real essences of bodies, of the causal processes underlying the production of natural phenomena, and of God's method of creation. I show how this epistemic humility offers strong support for an agnostic response to the question of superaddition. Locke did not intend to claim that bodies either do or do not have properties unrelated to their real essences. Instead, his primary goal in discussing the topic was to emphasize the strict limits to human knowledge.     

Scepticism,relativism, and the structure of epistemic frameworks

This paper has four aims: first, to outline the role of the sceptical problem of the criterion in the principal argument for epistemic relativism; second, to establish that methodist and particularist responses to the problem of the criterion do not, by themselves, constitute successful strategies for resisting epistemic relativism; third, to argue that a more fruitful strategy is to attempt to evaluate epistemic frameworks on the basis of the epistemic resources that they have in common; and finally, to make the case that finding this common ground will necessarily involve determining how it is that a framework’s constituent epistemic methods depend on one another for not only their warrant, but for their application.     

Values in pure and applied science

In pure science, the standard approach to non-epistemic values is to exclude them as far as possible from scientific deliberations. When science is applied to practical decisions, non-epistemic values cannot be excluded. Instead, they have to be combined with (value-deprived) scientific information in a way that leads to practically optimal decisions. A normative model is proposed for the processing of information in both pure and applied science. A general-purpose corpus of scientific knowledge, with high entry requirements, has a central role in this model. Due to its high entry requirements, the information that it contains is sufficiently reliable for the vast majority of practical purposes. However, for some purposes, the corpus needs to be supplemented with additional information, such as scientific indications of danger that do not satisfy the entry requirements for the corpus. The role of non-epistemic values in the evaluation of scientific information should, as far as possible, be limited to determining the level of evidence required for various types of practical decisions.     

Modelling and representing: An artefactual approach to model-based representation

The recent discussion on scientific representation has focused on models and their relationship to the real world. It has been assumed that models give us knowledge because they represent their supposed real target systems. However, here agreement among philosophers of science has tended to end as they have presented widely different views on how representation should be understood. I will argue that the traditional representational approach is too limiting as regards the epistemic value of modelling given the focus on the relationship between a single model and its supposed target system, and the neglect of the actual representational means with which scientists construct models. I therefore suggest an alternative account of models as epistemic tools. This amounts to regarding them as concrete artefacts that are built by specific representational means and are constrained by their design in such a way that they facilitate the study of certain scientific questions, and learning from them by means of construction and manipulation.     

Science,politics and regulation: The trust-based approach to the demarcation problem

Drawing on literature on values in science and a case-study of UK cancer policy, this paper argues for a novel account of the demarcation project in terms of trustworthiness. The first part of the paper addresses the relationship between science, politics and demarcation. In 2010, the UK government decided to pay more for cancer drugs than for drugs for other diseases; in 2016, this Cancer Drugs Fund was reformed so as to lower the evidential standards for approving cancer drugs, rather than paying more for them. Are these two ways of treating cancer as “special” importantly different? This paper argues that, if we the argument from inductive risk seriously, they seem equivalent. This result provides further reason to doubt the notion of demarcating science from non-science. However, the second part of the paper complicates this story, arguing that considerations of epistemic trust might give us reasons to prefer epistemic communities centred around “broadly acceptable” standards, and which are “sociologically well-ordered”, regardless of inductive risk concerns. After developing these claims through the cancer case-study, the final section suggests how these concerns might motivate novel versions of the demarcation project.     

Examining tensions in the past and present uses of concepts

Examining tensions between the past and present uses of scientific concepts can help clarify their contributions as tools in experimental practices. This point can be illustrated by considering the concepts of mental imagery and hallucinations: despite debates over their respective referential reliabilities remaining unresolved within their interdependent histories, both are used as independently stable concepts in neuroimaging experiments. Building on an account of how these concepts function as tools structured for pursuit of diverging goals in experiments, this paper explores this tension by re-examining the continued reliance of each concept on inverse characterisations inherited from the nominally-discarded ‘mediator-view’ of sensory-like mental phenomena (SLMP). In doing so, I seek to demonstrate how examining unresolved tensions can help highlight that entrenched associations can remain both integral to, and obscured by, the uses of concepts as goal-directed tools within experimental practices.     

知识、运气与德性

本文旨在概述一种反运气的德性知识论观点.这一知识论理论综合了反运气条件与德性条件,因此能化解与之相竞争的其它知识论观点所面对的困难,这尤其是针对稳健的德性知识论(robust virtueepistemology)而言的.具体来说,反运气的德性知识论能够解释知识对外部因素的依赖关系,也能够避免知识论意义上的“孪生地球”论证所提出的困难.自从盖梯尔(Gettier 1963)的著名文章挑战了知识作为“得到辩护的真信念”的三元定义以来,知识论学者对于提供知识的分析定义的前景越来越感到怀疑,尤其怀疑这种知识的分析能否有见识且不落入循环定义.我试图表明,应该追求的目标乃是对知识的一种有见识的分析,而不必一定是非循环的分析.尽管避免分析上的循环这一点也很诱人,但也并非所有循环的分析都毫无见识.哲学概念向来有可能交互定义彼此,因此从这些其它概念上我们也可以获得很多启示,而无需必要找到一条突破解释学循环的路径.盖梯尔反例明确提示我们,那种损毁知识的认知运气并不像传统上所理解的那样能由辩护条件来排除.一个人能有知识,就要求其认知成就不是偶然运气的产物.这是所谓反运气的直观.另一个显著的关于知识的直观是,知识要求认知成就以某种有意义的方式从认知能力获得,也就是说,这些成就应归功于相关认知能力的作用.稳健的德性知识论就立足于这种能力直观,更进一步提出认知成就不仅归功于而且就应产生于认知能动性,且满足这一点就同时满足了反运气的直观.然而实际上并非如此.我们可以用知识论意义上的“孪生地球”反例来证明这一点.这一反例的核心在于,两个认知者分别在地球和孪生地球上具有真信念,也同等地归功于认知能动性的发挥,但却仍然在认知运气方面存在差异.按照这一论证,地球与孪生地球上形成的真信念可以表现同等程度的认知能力,却因为受认知运气的不同影响产生不同的知识论地位.反运气的德性知识论化解了这个困难:“S知道p,当且仅当,S的认知成就是安全的,体现了S的相关认知能力,且这一安全的认知成就在相当程度上归功于S的这些认知能力的作用.”首先,它用安全性原则把握知识的反运气条件,主张作为知识的真信念不能轻易为假;其次,它强化了认知成就的安全性要求,同时弱化了能力直观,即不要求认知成就产生于能力,而仅要求其可归功于认知能力,从而在强弱两方面都改造了稳健的德性知识论;最后,即便反运气的德性知识论未必是非循环的知识分析,它也依然有助于理解认知运气、认知能力与知识等概念间的相互关联,从而仍然是有见识的知识论分析.     

Inevitability,contingency, and epistemic humility

This paper offers an epistemological framework for the debate about whether the results of scientific enquiry are inevitable or contingent. I argue in Sections 2 and 3 that inevitabilist stances are doubly guilty of epistemic hubris—a lack of epistemic humility—and that the real question concerns the scope and strength of our contingentism. The latter stages of the paper—Sections 4 and 5—address some epistemological and historiographical worries and sketch some examples of deep contingencies to guide further debate. I conclude by affirming that the concept of epistemic humility can usefully inform critical reflection on the contingency of the sciences and the practice of history of science.