History and many-worlds quantum theory

Ig. Tamm

Don Nelson Page

Contrary to an oft-made claim, there can be observational distinctions (say for the expansion of the universe or the cosmological constant) between "single-history" quantum theories and "many-worlds" quantum theories. The distinctions occur when the number of observers is not uniquely predicted by the theory. In single-history theories, each history is weighted simply by its quantum-mechanical probability, but in many-worlds theories in which random observations are considered, there should also be the weighting by the numbers or amounts of observations occurring in each history.

Akira Morikawa

[概要]本研究ノートは後続する量子論の歴史に対する序論である. 現代と19世紀の間にある種の深い断絶があるように量子論と古典物理学の間にも断絶が存在する. ここに量子の歴史をあらためて記してみる意義がある. 本論では, 19世紀の物理学（古典物理学）の世界観と量子を生み出す社会の直接的な要因と目されるその社会状況を概観しておく. また, 現代がいかに視角や展望を必要としているかについても若干の私論を展開しておくものである. [Abstract] This paper is an introduction for the history of quantum theory that I will write on the subsequent articles. To write the history of quantum is important because we are living in the modern scientific civilization. However, we have deep chasms between classical 19th century world and the modern world. There are also chasms between classical physics and the quantum modern physics. We will argue a world-picture of the classical physics and social circumstances which provided for the birth of the quantum in this paper. And this paper states and expounds the necessity of the perspective into our era as my personal views too.

Helena Reymond, Loı̈c M. Roch

Bruce S. Bennett, Moletlanyi Tshipa

Abstract The Many-Worlds Interpretation (MWI) is a theory in physics which proposes that, rather than quantum-level events being resolved randomly as according to the Copenhagen Interpretation, the universe constantly divides into different versions or worlds. All physically possible worlds occur, though some outcomes are more likely than others, and therefore all possible histories exist. This paper explores some implications of this for history, especially concerning causation. Unlike counterfactuals, which concern different starting conditions, MWI concerns different outcomes of the same starting conditions. It is argued that analysis of causation needs to take into account the divergence of outcomes and the possibility that we inhabit a less probable world. Another implication of MWI is convergent history: for any given world there will be similar worlds which are the result of different pasts which are, however, more or less probable. MWI can assist in thinking about historical causation and indicates the importance of probabilistic causation.

Jagdish Mehra, Helmut Rechenberg