Model-theoretic argument

This tacit commitment to (IR1) shows that the internal realist account of reference is indeed a species of the anti-realist answer to the skeptical challenge. The challenge, posed by Putnam s model-theoretic argument was this. If the structure of the world were independent of the human mind, how could concepts and words, which are human inventions, refer to the elements of the structure The answer provided here is that the structure of the world is not independent of the mind. The criteria of identity for entities derive from the justification conditions which govern the use of concepts. So the entities out there and the entities our words are intended to apply to are bound to be the same. We should not be surprised that the top slices meet the bottom slices. We just slice from the top and reach the bottom. 

Landini, Gregory. Putnam s Model-Theoretic Argument Natural Realism, and the Standard Conception of Theories. Philosophical Papers 16 (1987) 209-233. 

Merril, G. H. The Model-Theoretic Argument Against Realism. Philosophy of Science 47 (1980) 69-81. 

Taylor, Barry. Just More Theory A Manoeuvre in Putnam s Model-Theoretic Argument for Anti-Realism. Australasian Journal of Philosophy 69 (1991) 152-166. 

The above effects are more familiar than direct contributions of the metal s components to the properties of the interface. In this chapter, we are primarily interested in the latter these contribute to M(S). The two quantities M(S) and S(M) (or 8% and S m) are easily distinguished theoretically, as the contributions to the potential difference of polarizable components of the metal and solution phases, but apparently cannot be measured individually without adducing the results of calculations or theoretical arguments. A model for the interface which ignores one of these contributions to A V may, suitably parameterized, account for experimental data, but this does not prove that the neglected contribution is not important in reality. Of course, the tradition has been to neglect the metal s contribution to properties of the interface. Recently, however, it has been possible to use modern theories of the structure of metals and metal surfaces to calculate, or, at least, estimate reliably, xM(S) and 5 (as well as discuss 8 m, which enters some theories of the interface). It is this work, and its implications for our understanding of the electrochemical double layer, that we discuss in this chapter. 

It is important to note that theoretic argument and empiric study have shown that the LOO cross-validation approach is preferred to the use of an external test set for small to moderate sized chemical databases [39]. The problems with holding out an external test set include (1) structural features of the held out chemicals are not included in the modeling process, resulting in a loss of information, (2) predictions are made only on a subset of the available compounds, whereas LOO predicts the activity value for all compounds, and (3) personal bias can easily be introduced in selection of the external test set. The reader is referred to Hawkins et al. [39] and Kraker et al. [40] in addition to Section 31.6 for further discussion of proper model validation techniques. 

It is shown that model, end-linked networks cannot be perfect networks. Simply from the mechanism of formation, post-gel intramolecular reaction must occur and some of this leads to the formation of inelastic loops. Data on the small-strain, shear moduli of trifunctional and tetrafunctional polyurethane networks from polyols of various molar masses, and the extents of reaction at gelation occurring during their formation are considered in more detail than hitherto. The networks, prepared in bulk and at various dilutions in solvent, show extents of reaction at gelation which indicate pre-gel intramolecular reaction and small-strain moduli which are lower than those expected for perfect network structures. From the systematic variations of moduli and gel points with dilution of preparation, it is deduced that the networks follow affine behaviour at small strains and that even in the limit of no pre-gel intramolecular reaction, the occurrence of post-gel intramolecular reaction means that network defects still occur. In addition, from the variation of defects with polyol molar mass it is demonstrated that defects will still persist in the limit of infinite molar mass. In this limit, theoretical arguments are used to define the minimal significant structures which must be considered for the definition of the properties and structures of real networks. 

We usually seek to distinguish between two possibilities (a) the null hypothesis—a conjecture that the observed set of results arises simply from the random effects of uncontrolled variables and (b) the alternative hypothesis (or research hypothesis)—a trial idea about how certain factors determine the outcome of an experiment. We often begin by considering theoretical arguments that can help us decide how two rival models yield nonisomorphic (i.e., characteristically different) features that may be observable under a certain set of imposed experimental conditions. In the latter case, the null hypothesis is that the observed differences are again haphazard outcomes of random behavior, and the alternative hypothesis is that the nonisomorphic feature(s) is (are) useful in discriminating between the two models. 

Because of its intuitive appeal and its high degree of accuracy, the VSEPR model has been well received by inorganic chemists, but the theoretical basis has been a matter of some dispute.22 More recently, there have been strong theoretical arguments for localized, stereochemically active orbitals.22... 

Empirical modeling. When the model is too complex or some defined knowledge is missing, approximations of theory are used to implement the theoretical arguments. 

The conjugated-circuits model is one of the simplest quantitative models that has been reasonably well studied. As already mentioned this model may be motivated from classical chemical bonding theory (extended a la Clar s classical empiricist argument) or from Simpson s existential quantum-theoretic argument [ 121 ], or from a quantum chemical derivation indicated in our hierarchy of section 3.2. But beyond derivation of the model there is the question of its solution, such as we now seek to address. 

This is a simplified version of Anthony Brueckner s ( Putnam s Model-Theoretic ) reconstruction of the argument. Most other reconstructions consider only one horn of the dilemma, the first disjunct of (PI), (P3) and (C). The various reconstructions in the literature differ only in small details which are not relevant from the present point of view. I could have used almost any one of them to make my point, but Brueckner s reconstruction makes this especially easy. For further details see Harrison ( Putnam on Brains ), Casati and Dokic ( Brains in a Vat ), David ( Neither Mentioning ), Tymoczko( In Defense , Brains Don t Lie ), Tichy ( Putnam on Brains ), Farrell ( Putnam on the Vat-People ), Kinghon ( External World ), Van Kirk ( Kant s Reply ), Heil ( Epistemic Route ), Sacks (The World, 56-76)), Nagel (The View From Nowhere, 71-4), Dell Utri ( The Case of the Brains ), Collier ( Could I... 

Note that the crisis of the GME method, based on the density approach, is generated by non-Poisson renewal processes. Therefore, we find it important to illustrate, by means of Section V, the model for intermittence, on which our theoretical arguments are based. 

Examples of photoreactions may be found among nearly all classes of organic compounds. From a synthetic point of view a classification by chromo-phore into the photochemistry of carbonyl compounds, enones, alkenes, aromatic compounds, etc., or by reaction type into photochemical oxidations and reductions, eliminations, additions, substitutions, etc., might be useful. However, photoreactions of quite different compounds can be based on a common reaction mechanism, and often the same theoretical model can be used to describe different reactions. Thus, theoretical arguments may imply a rather different classification, based, for instance, on the type of excited-state minimum responsible for the reaction, on the number and arrangement of centers in the reaction complex, or on the number of active orbitals per center. (Cf. Michl and BonaCid-Kouteck, 1990.)... 

What value of a corresponds to the double reptation model In Section 9.3, we have presented theoretical arguments and experimental data supporting the value a =4/3 in -solvents (and melts with ideal chain statistics). What is the expression of the stress relaxation modulus of tube dilation models corresponding to a = 4/3 ... 

Historically, this form of the excess Gibbs energy was suggested as the simplest function which obeys the requirements that g iX,S[ must be zero when either xA — 0 or X/j —> 0. This is known as Margules equation, see, e.g., Prausnitz et al (1986). From (L.6), one can obtain both equations (L.3) and (L.4). The latter was derived from theoretical arguments based on lattice model for mixtures (Guggenheim 1952). 

Similar ideas will be further developed in the next section, along with some other criteria and requirements. In our opinion, a strict adherence to them would improve the efficiency of the interaction between experimentation and modeling. To conclude this section, let us formulate in brief the main tasks addressed concerning the comparison of modeling with experimental data as far as the optimization of the model targeted toward the studies of the reaction mechanism and process optimization over a wide range of parameters are concerned. In our opinion, such comparison must reveal the factors that have been underestimated and overestimated in the kinetic scheme. As to the values of kinetic parameters, they definitely can be optimized , but this optimization should be based on exact physical and chemical (experimental and theoretical) arguments, but not on formal mathematical procedures. 

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