•  57
    This paper, part I of a two-part project, aims at answering the simple question 'what is spontaneous symmetry breaking?' by analyzing from a philosophical perspective a simple classical model. Related questions include: what does it mean to break a symmetry spontaneously? Is the breaking causal, or is the symmetry not broken but merely hidden? Is the meta-principle, 'no asymmetry in, no asymmetry out,' violated? And what is the role in this of random perturbations (or fluctuations)?
  •  31
    Models and theories II: Issues and applications
    International Studies in the Philosophy of Science 12 (2). 1998.
    This paper is the second of a two-part series on models and theories, the first of which appeared in International Studies in the Philosophy of Science, Vol. 11, No. 2, 1997. It further explores some of themes of the first paper and examines applications, including: the relations between “similarity” and “isomorphism”, and between “model” and “interpretation”, and the notion of structural explanation.
  •  44
    Over forty years after the foundations of the special theory of relativity had been securely laid, a heated debate, beginning in 1965, about the correct formulation of relativistic thermodynamics raged in the physics literature. Prior to 1965, relativistic thermodynamics was considered one of the most secure relativistic theories and one of the most simple and elegant examples of relativization in physics. It is, as its name apparently suggests, the result of the application of the special theor…Read more
  •  120
    In this paper, I begin with a discussion of Giere’s recent work arguing against taking models as works of fiction. I then move on to explore a spectrum of scientific models that goes from the obviously fictional to the not so obviously fictional. And then I discuss the modeling of the unobservable and make a case for the idea that despite difficulties of defining them, unobservable systems are modeled in a fundamentally different way than the observable systems. While idealization and approxi…Read more
  •  33
    This paper, part II of a two-part project, continues to explore the meaning of spontaneous symmetry breaking (SSB) by applying and expanding the general notion we obtained in part I to some more complex and, from the physics point of view, more important models (in condensed matter physics and in quantum field theories).
  •  95
    Our discussion in the first five sections shows that little new can be said about compatibilism, that van Inwagen's argument for incompatibilism still stands, and that the view of free agency for a libertarian has little chance unless she believes that agency contains elements that are not within the natural order. Borrowing from a suggestion from Russell we expanded the Nozick-Kane model of libertarian free agency and connected it to the Wignerian interpretation of quantum measurement. As such,…Read more
  •  12
    Coins and Electrons: A Unified Understanding of Probabilistic Objects
    Poznan Studies in the Philosophy of the Sciences and the Humanities 71 243-260. 2000.
  •  18
    This paper contains four variations on Duhem's theme about the contrast between the abstract French mind and the concrete British mind. The first variation brings out the real contrast between two types of methods and their results: the A method or models and the C method or models. The second variation gives a critical discussion of the Callender-Cohen deflationary contruel of scientific representation. The third variation discusses Russell's structuralism in connection to the theme. And the fo…Read more
  •  117
    Models and theories I: The semantic view revisited
    International Studies in the Philosophy of Science 11 (2). 1997.
    The paper, as Part I of a two-part series, argues for a hybrid formulation of the semantic view of scientific theories. For stage-setting, it first reviews the elements of the model theory in mathematical logic (on whose foundation the semantic view rests), the syntactic and the semantic view, and the different notions of models used in the practice of science. The paper then argues for an integration of the notions into the semantic view, and thereby offers a hybrid semantic view, which at once…Read more
  •  143
    Explaining quantum spontaneous symmetry breaking
    with Gérard G. Emch
    Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 36 (1): 137-163. 2005.
    Two alternative accounts of quantum spontaneous symmetry breaking (SSB) are compared and one of them, the decompositional account in the algebraic approach, is argued to be superior for understanding quantum SSB. Two exactly solvable models are given as applications of our account -- the Weiss-Heisenberg model for ferromagnetism and the BCS model for superconductivity. Finally, the decompositional account is shown to be more conducive to the causal explanation of quantum SSB.
  •  295
    This paper defends an approach to modeling and models in science that is against model fictionalism of a recent stripe (the “new fictionalism” that takes models to be abstract entities that are analogous to works of fiction). It further argues that there is a version of fictionalism on models to which my approach is neutral and which only makes sense if one adopts a special sort of antirealism (e.g. constructive empiricism). Otherwise, my approach strongly suggests that one stays away from fic…Read more
  •  208
    The aharonov-Bohm effect and the reality of wave packets
    British Journal for the Philosophy of Science 45 (4): 977-1000. 1994.
    The objective of this paper is to show that, instead of quantum probabilities, wave packets are physically real. First, Cartwright's recent argument for the reality of quantum probabilities is criticized. Then, the notion of ‘physically real’ is precisely defined and the difference between wave functions and quantum probabilities clarified. Being thus prepared, some strong reasons are discussed for considering the wave packet to be physically real. Finding the reasons inconclusive, I explain how…Read more
  •  28
    This paper examines the justifications for using infinite systems to ‘recover’ thermodynamic properties, such as phase transitions, critical phenomena, and irreversibility, from the micro-structure of matter in bulk. Section 2 is a summary of such rigorous methods as in taking the thermodynamic limit to recover PT and in using renormalization group approach to explain the universality of critical exponents. Section 3 examines various possible justifications for taking TL on physically finite sys…Read more
  •  46
    In this essay, I explore a metaphor in geometry for the debate between the unity and the disunity of science, namely, the possibility of putting a global coordinate system (or a chart) on a manifold. I explain why the former is a good metaphor that shows what it means (and takes in principle) for science to be unified. I then go through some of the existing literature on the unity/disunity debate and show how the metaphor sheds light on some of the views and arguments.
  • Relativistic Thermodynamics: Its History and Foundations
    Dissertation, University of Pittsburgh. 1991.
    Relativistic Thermodynamics of equilibrium processes has remained a strange chapter in the history of modern physics. It was established by Planck in 1908 as a simple application of Einstein's special theory of relativity. Einstein himself made substantial contributions and its final product remained officially unchallenged until 1965. In 1952, however, at the end of his career, Einstein challenged the theory in his correspondence with von Laue. Many of his unpublished suggestions anticipated th…Read more
  •  109
    Explaining the emergence of cooperative phenomena
    Philosophy of Science 66 (3): 106. 1999.
    Phase transitions are well-understood phenomena in thermodynamics (TD), but it turns out that they are mathematically impossible in finite SM systems. Hence, phase transitions are truly emergent properties. They appear again at the thermodynamic limit (TL), i.e., in infinite systems. However, most, if not all, systems in which they occur are finite, so whence comes the justification for taking TL? The problem is then traced back to the TD characterization of phase transitions, and it turns out t…Read more
  •  157
    Re-inflating the Conception of Scientific Representation
    International Studies in the Philosophy of Science 29 (1): 41-59. 2015.
    This article argues for an anti-deflationist view of scientific representation. Our discussion begins with an analysis of the recent Callender–Cohen deflationary view on scientific representation. We then argue that there are at least two radically different ways in which a thing can be represented: one is purely symbolic, and therefore conventional, and the other is epistemic. The failure to recognize that scientific models are epistemic vehicles rather than symbolic ones has led to the mistake…Read more