The Internal and External Problems of String Theory: A Philosophical View

Abstract

String theory is at the moment the only advanced approach to a unification of all interactions, including gravity.But, in spite of the more than thirty years of its existence, it does not make any empirically testable predictions, and it is completely unknown which physically interpretable principles could form the basis of string theory. At the moment, "string theory" is no theory at all, but rather a labyrinthic structure of mathematical procedures and intuitions. The only motivations for string theory consist in the mutual incompatibility of the standard model of quantum field theory and of general relativity as well as in the metaphysics of the unification program of physics, aimed at a final unified theory of all interactions, including gravity. The article gives a perspective on the problems leading to and resulting from this situation. String Theory and Philosophy of ScienceSome physicists seem to take it for sure that string theory 4 is the adequate theory of quantum gravity and the ultimate theory of nature."I believe that we have found the unique mathematical structure that consistently combines quantum mechanics and general relativity. So it must almost certainly be correct." (Schwarz (1998) 2) Others see in it the ultimate hype in which the ideals of physics as an empirical science get lost. But what is string theory really? -There are certainly good reasons to claim that this question can not be answered conclusively at the moment, because string theory isn't yet a complete theory. 't know." (Susskind (2005) 124) "Elegance requires that the number of defining equations be small. Five is better than ten, and one is better than five. On this score, one might facetiously say that String Theory is the ultimate epitome of elegance. With all the years that String Theory has been studied, no one has ever found even a single defining equation! The number at present count is zero. We know neither what the fundamental equations of the theory are nor even if it has any. Well then, what is the theory, if not a collection of defining equations? We really donAlready in 1988, after the first wave of string enthusiasm which started with the development of the first consistent anomaly-free perturbative supersymmetric string theories, Robert Weingard wrote in his paper A Philosopher Looks at String Theory: " [...] there is, in a sense, no theory for the philosopher to analyse." (Weingard (1989) 138) In a certain way, the conditions for an evaluation of string theory did not change a lot since Weingard's assessment -an assessment which did not prevent him from writing his paper on the subject. Although string theory is at present the most extensively developed approach to a future theory of quantum gravity, it seems to be a rather confusing collection of physical intuitions and mathematical procedures which either will or will not lead finally to a physical theory. At the moment, string theory has no clear and unambiguous nomological basis; no physically motivated fundamental principle is known for ...

Quantum gravitational applications of nuclear, atomic and astrophysical phenomena

“…If one is willing to consider this fact as a real inadequacy of current unified physics models, the proposed two gravitational constants can be recommended for indepth study at fundamental level. From unification point of view, one can find many critical reviews on the foundations, predictions, current status and success of string theory in physics literature [68][69][70][71]. Reiner Hedrichsays [71]: "String theory is at the moment the only advanced approach to a unification of all interactions, including gravity.…”

“…From unification point of view, one can find many critical reviews on the foundations, predictions, current status and success of string theory in physics literature [68][69][70][71]. Reiner Hedrichsays [71]: "String theory is at the moment the only advanced approach to a unification of all interactions, including gravity. But, in spite of the more than thirty years of its existence, it does not make any empirically testable predictions, and it is completely unknown which physically interpretable principles could form the basis of string theory.…”

String Theory, the Crisis in Particle Physics and the Ascent of Metaphoric Arguments

“…This intention to go to the conceptual roots also separates the content of the present reworked presentation from its previous version, as well as from the various string-critical books, articles and published statements by particle physicist, philosophers and condensed matter physicists as P. Woit [3], L. Smolin [4] and R. Hedrich [5]. In those articles the consistency of its conceptualmathematical framework was not the issue; their content is not directed to test the mathematical-conceptual consistency of string theory but their main concern is the lack of tangible results despite of more than four decades of work by hundreds of brilliant minds and, particularly in case of Lee Smolin, the resulting futile consummation of valuable resources 3 .…”

“…Using more adequate mathematical tools in conjunction with a minimality principle which limits the short distance singularity of the undetermined total diagonal contribution in terms of the scaling degree of the uniquely determined non-diagonal part [8], one finds that there are local couplings between pointlike fields for which the perturbative iteration either does not require more parameters than there were in the beginning, or adds only a finite number of new couplings which one could have already included in the starting interaction ex-pressed in terms of Wick-product of free fields 5 . The renormalized theory forms a finite parameter space on which the (Petermann-Stueckelberg) renormalization group acts ergodically.…”

An apology for conflicts between metaphysics and science in naturalized metaphysics

“…However, what new metaphysics that science replaces these with will only be revealed if we remember to probe the metaphysics of a scientific theory and not simply end our inquiry -as naturalized metaphysics sometimes seems to recommend -when science proves our held metaphysical beliefs wrong. The presence of conflicts between metaphysics and 4 Obviously, this ruling relies on an appropriate demarcation between physics (and science in general) and wild speculation that may happen to involve some mathematical formalism; some might worry that some theories of quantum gravity are examples of the latter (see for instance Hedrich (2007) for a discussion of this and similar questions in relation to string theory). This issue will be set aside here for the reason also discussed further in footnote 17 that the present apology for conflicts between metaphysics and science does not rely on the assumption that the scientific theories in question are speculative or yet to receive proper empirical confirmation.…”