A Third Route to the Doomsday Argument

DA-figureA paper published (2009) in English in the Journal of Philosophical Research, vol. 34, pages 263-278 (with significant changes with regard to the preprint).

In this paper, I present a solution to the Doomsday argument based on a third type of solution, by contrast with, on the one hand, the Carter-Leslie view and on the other hand, the Eckhardt et al. analysis. I begin by strengthening both competing models by highlighting some variations of their ancestors models, which renders them less vulnerable to several objections. I describe then a third line of solution, which incorporates insights from both Leslie and Eckhardt’s models and fits more adequately with the human situation corresponding to the Doomsday argument. I argue then that the resulting two-sided analogy casts new light on the reference class problem. This leads finally to a novel formulation of the argument that could well be more consensual than the original one.

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A Third Route to the Doomsday Argument

In what follows, I will endeavor to present a solution to the problem arising from the Doomsday argument (DA). The solution thus described constitutes a third way out, compared to, on the one hand, the approach of the promoters of DA (Leslie 1993 and 1996) and on the other hand, the solution recommended by its detractors (Eckhardt 1993 and 1997, Sowers 2002).i

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Probabilistic Situations for Goodmanian N-universes

image22A paper appeared (2006) in French in the Journal of Philosophical Research, vol. 31, pages 123-141, under the title “Situations probabilistes pour n-univers goodmaniens.”

I proceed to describe several applications of the theory of n-universes through several different probabilistic situations. I describe first how n-universes can be used as an extension of the probability spaces used in probability theory. The extended probability spaces thus defined allow for a finer modelling of complex probabilistic situations and fits more intuitively with our intuitions related to our physical universe. I illustrate then the use of n-universes as a methodological tool, with two thought experiments described by John Leslie. Lastly, I model Goodman’s paradox in the framework of n-universes while also showing how these latter appear finally very close to goodmanian worlds.

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Probabilistic Situations for Goodmanian N-universes

The n-universes were introduced in Franceschi (2001, 2002) in the context of the study of the probabilistic situations relating to several paradoxes which are currently the object of intensive studies in the field of analytical philosophy: Goodman’s paradox and the Doomsday Argument. The scope of the present article is twofold: on one hand, to describe how modelling within the n-universes allows to extend the properties of the classical probability spaces used in probability theory, by providing at the same time a finer modelling of some probabilistic situations and a better support for intuition; on the other hand, to show how the use of n-universes allows to simplify considerably the study of complex probabilistic situations such as those which appear in the study of paradoxes.

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Post-publication of a review of John Leslie, Infinite Minds

Review of John Leslie, Infinite Minds, Oxford, Oxford University Press, 2001, 234 pages.1john leslie infinite minds

 Paul Franceschi

 University of Corsica

 

Post-publication of the review appeared in Philosophiques, Volume 30, number 2, Autumn 2003

Infinite Minds is the fourth book of John Leslie, which follows Value and Existence (1979), Universes (1989) and The End of the World (1996). Infinite Minds presents a very rich content, and covers a number of particularly varied subjects. Among these latter, one can notably mention: omniscience, the problem of Evil, the fine-tuning argument, observational selection effects, the identity of indiscernables, time, infiniteness, the nature of consciousness.

The book places itself clearly within the field of speculative philosophy. And Leslie is primarily concerned here with considerations not of rigorous demonstration, but rather of plausibility and of coherence. He thus does not hesitate sometimes to attribute a rather weak probability to certain assertions.

Some readers may be rebutted from the beginning by the counter-intuitive assertion that galaxies, planets, animals, but also each of us and our surrounding objects, are mere structures among divine thoughts. One can think that such an assertion has motivated the commentary placed on the book’s cover by a reader from Oxford University Press, according to which it may be difficult to believe that the universe is such that the author describes it. This was also my primary reaction. But if certain readers were to draw from that a hasty conclusion, they would miss then, I think, what constitutes the hidden treasure of the book. Because Infinite Minds resembles a sumptuous temple, whose access however is dissimulated by a gate which looks poorly attractive. Those who will not cross the door, rebutted by the aspect of this latter, will not have the occasion to contemplate the hidden treasures that the book contains. Because the book presents an overall deep structure and coherence, based on the consistency of the author’s pantheist conception of the universe with our current most advanced scientific views with regard to cosmology, physics, as well as with the solutions to several contemporary philosophical problems. To show synthetically how a pantheist vision of the world can cohere with our most recent views with regard to multiple universes, physics and quantum computer science, inasmuch as with relativity theory and recent discussions relating to omniscience, the problem of Evil, the fine-tuning argument, observational selection effects, etc. appears both an immense and deeply original task.

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The Doomsday Argument and Hempel’s Problem

hempelPosprint in English (with additional illustrations) of a paper published in French in the Canadian Journal of Philosophy Vol.29, July 1999, pp. 139-56 under the title “Comment l’Urne de Carter et Leslie se Déverse dans celle de Hempel”.
I begin by describing a solution to Hempel’s Problem. I recall, second, the solution to the Doomsday Argument described in my previous Une Solution pour l’Argument de l’Apocalypse (Canadian Journal of Philosophy 1998-2) and remark that both solutions are based on a similar line of reasoning. I show thirdly that the Doomsday Argument can be reduced to the core of Hempel’s Problem.

This paper is cited in:

Koji Sawa, Junki Yokokawa and Tatsuji Takahashi (2013) Logical Equivalence: Symmetric and Asymmetric Features, Symmetry: Culture and Science, Vol. 24, No. x.

Milan M. Cirkovic, A Resource Letter on Physical eschatology, Am.J.Phys. 71 (2003) 122-133

Nick Bostrom, Anthropic Bias: Observation Selection Effects in Science and Philosophy, Routledge (2002)

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