Online research in philosophy

The discovery that the universe is fine-tuned for life ? a discovery to which the phrase ?the anthropic principle? is often applied ? has prompted much extra-cosmic speculation by philosophers, theologians, and theoretical physicists. Such speculation is referred to as extra-cosmic because an inference is made to the existence either of one unobservable entity that is distinct from the cosmos and any of its parts (God) or of many such entities (multiple universes). In this article a case is mounted for the sceptical position that cosmic fine-tuning does not support an inference to anything extra-cosmic. To that end three definitions of ?fine-tuned for life? are proposed: the ?slight difference? definition, the (unconditional) probability definition, and John Leslie?s conditional probability definition. These three definitions are the only ones suggested by the relevant literature on fine-tuning and the anthropic principle. Since on none of them do claims of fine-tuning warrant an inference to something extracosmic, it is concluded that there is no definition of ?fine-tuned for life? serving this function.

Evidence for instances of astrophysical 'fine tuning' (or 'coincidences') is thought by some to lend support to the design argument (i.e. the argument that our universe has been designed by some deity). We assess some of the relevant empirical and conceptual issues. We argue that astrophysical fine tuning calls for some explanation, but this explanation need not appeal to the design argument. A clear and strict separation of the issue of anthropic fine tuning on one hand and any form of Eddingtonian numerology and teleology on the other, may help clarify arguably the most significant issue in the philosophy of cosmology.

The claim that certain fundamental constants of nature are fine tuned for life and that this provides strong evidence for supernatural design is perhaps the best scientific argument for the existence of God since Paley’s watch. Even atheist physicists find these so called “anthropic coincidences” difficult to explain and need to invoke the Weak Anthropic Principle and multiple universes to do so. Certainly if there are many universes, fine tuning is simple. Our form of life was fined tuned to our universe by evolution. While multiple universes are expected from modern cosmological theories, theists and some scientists object that invoking the unobservable is not science. Of course, God is unobservable too, so the best theists can claim is a standoff. This is the first in a series of columns based on a book in the works that attempts to show that the apparent fine tuning of fundamental constants can be understood from basic physics without invoking multiple universes. In some cases the explanation is provable. In other cases, it is not provable but plausible. Fine tuning by design is a God of the Gaps argument. The proponent has the burden if proving that no possible natural explanation can be found. Thus a plausible natural explanation is sufficient to defeat the argument. A list of thirty four parameters that seem to be fine tuned has been assembled by Rich Deem on the God and Science website. Several of Deem’s constants, such as the speed of light in a vacuum, c, Newton’s constant of gravity, G, and Planck’s constant, h, are just arbitrary numbers that are determined simply by the unit system you are using. They can be set equal to any number you want, except zero, with no impact on the physics. So no fine tuning can possibly be involved, just as the number p is not fine tuned. I will focus first on the five parameters that have the most significance because, if interpreted correctly, they seem to pretty much rule out almost any conceivable kind of life without fine tuning: · Ratio of electrons to protons · Ratio of electromagnetic force to gravity Expansion rate of the universe · Mass density of the universe · Cosmological constant I will admit that the features a universe would have for slightly different values of these parameters, all other parameters remaining the same, would render unlikely any form of life even remotely like ours, that is, one that is based on a lengthy process, chemical or otherwise, by which complex matter evolved from simpler matter. Let me discuss each in turn, with the last, the most difficult, reserved for a future column..

William Dembski claims that the fine-tuning supports the inference that the universe was designed. His ‘design inference’ is based on the identification of two features of the fine-tuning. Dembski claims that it is a ‘specified’ event of small (a priori) probability. Specification, in this context, is the ability to describe an event without using any knowledge of the actual event itself. I argue that we currently do not have the ability to describe accurately the fine-tuning of the universe without using any knowledge of the fine-tuning itself. If we cannot generate a specification, then the fine-tuning is not a specified event, so the ‘design inference’ is not justified.

Many theists regard the claim that certain fundamental constants of nature are fine-tuned for life as the best scientific argument for the existence of God since Paley’s watch. Even atheist physicists find these so-called “anthropic coincidences” difficult to explain naturally and many think they need to invoke multiple universes and the so-called “anthropic principle” to do so. Certainly if there are many universes, fine-tuning is simple. Our universe is not fine-tuned for life. Life is fine-tuned to our universe. While multiple universes are expected from modern cosmological theories, theists and some scientists object that invoking the unobservable is not science. Of course, God is unobservable too, so the best theists can claim is a standoff.

The argument from fine tuning is supposed to establish the existence of God from the fact that the evolution of carbon-based life requires the laws of physics and the boundary conditions of the universe to be more or less as they are. We demonstrate that this argument fails. In particular, we focus on problems associated with the role probabilities play in the argument. We show that, even granting the fine tuning of the universe, it does not follow that the universe is improbable, thus no explanation of the fine tuning, theistic or otherwise, is required.

The Fine-tuning argument takes the existence of life as evidence that an agent had a hand in making the universe. The argument is thought to hinge on the claim that ‘fine-tuning’ of various parameters is required for life to evolve. Jonathan Weisberg argues that even granting that life can provide evidence for design, further data about the fine-tuning required add nothing to the case. Weisberg charges the argument rests on unsupported assumptions about a designer’s preference for a fine-tuned universe (over and above favouring life). I argue that he is mistaken. The assumptions that Weisberg grants (for the sake of argument) are sufficient to make fine-tuning relevant to design.

I argue that the standard way of formalizing the fine-tuning argument for design is flawed, and I present an alternative formalization. On the alternative formalization, the existence of life is not treated as the evidence that confirms design; instead it is treated as part of the background knowledge, while the fact that fine tuning is required for life serves as the evidence. I argue that the alternative better captures the informal line of thought that gives the fine-tuning argument its intuitive plausibility, and I show that the alternative formalization avoids all of the most prominent objections to the fine-tuning argument, including the objection from observation selection effects, the problem of old evidence, the problem of non-normalizable probability measures and a further objection due to Monton. I conclude that the alternative formalization is the one that attention should be focused on.

The Fine-Tuning Argument (FTA) is a variant of the Design Argument for the existence of God. In this paper the evidence of fine-tuning is explained and the Fine-Tuning Design Argument for God is presented. Then two objections are covered. The first objection is that fine-tuning can be explained in terms of the existence of multiple universes (the 'multiverse') plus the operation of the anthropic principle. The second objection is the 'normalizability problem'– the objection that the Fine-Tuning Argument fails because fine-tuning is not actually improbable.

The fundamental constants that are involved in the laws of physics which describe our universe are finely-tuned for life, in the sense that if some of the constants had slightly different values life could not exist. Some people hold that this provides evidence for the existence of God. I will present a probabilistic version of this fine-tuning argument which is stronger than all other versions in the literature. Nevertheless, I will show that one can have reasonable opinions such that the fine-tuning argument doesn’t lead to an increase in one’s probability for the existence of God.