摘要:

AbstractThe knowledge of an object under observation will have no concrete meaning unless we can work out a logical model the similarities of which are known in relation to the analysed structures. The logical model, when dealing with complex structures, is drawn out by similarity starting from an analogical model worked out in relating local dimensions in the object to physical dimensions of a different nature which restrict the number of variables and can be arranged and modified as required.Any operating similarity and behaviour comparisons come actually down to an apparent functional analogy. The difference between the thin structure of the natural and artificial systems makes it illusive to hope that a strict isomorphism between these two fields may thus be sorted out. However, the fact of achieving analogical models widens our knowledge and shows new possibilities to the human creative mind.

ISSN:0012-2017    

DOI:10.1111/j.1746-8361.1963.tb01566.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

AbstractAnalogy plays a basic part in engineering which is subject to certain limitations, due to the following reasons:— lack of accuracy of the measuring instruments and of computing data; — simplifying assumptions necessary for establishing the mathematic model; — restrictions due to compulsory computation means and time. The basic criterion of engineering knowledge is efficiency. The engineer works thus on successive approximations, each of them corresponding to a more or less appropriate model of the final result. In order to avoid disappointment, it is very important for him to be conscious of the relativity of his knowledge and of the scope of teh successive approximations. This procedure is the same for other fields of knowledge and provides an opportunity to specify the concept of rigour applying to each. It shows the practical, limited and revisable character of any knowledge not springing from metaph

ISSN:0012-2017    

DOI:10.1111/j.1746-8361.1963.tb01567.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

AbstractThe argument from analogy is examined from the standpoint of Carnap's confirmation theory. Carnap's own discussion of analogy in relation to his c*— function is restricted to cases where the analogues are known to be similar, but notknownto be different in any respect. It has been argued by the author in a previous work,(Models and Analogies in Science, 1963, p. 121), and by P. Achinstein (Phil. Sci, 30, 1963, 216), that typical analogy arguments involve known differences between the analogues as well as similarities. Achinstein shows that for such arguments none of Carnap's Δ— system of conflrmation functions gives satisfactory values, and it is further shown in the present paper that for these arguments the confirmation never rises above its initial value, irrespective of evidence drown from an analogue. it is argued that even ifinductivearguments are to be applicable to the real world, they must in principle be capable of taking into account known differences between the instances of an inductive generalization. Hence Carnap's Δ— system is inadequate as an explication of both induction and analogy.Three conditions are stated as necessary for any confirmation theory which gives a satisfactory explication of analogical inference:I. If two individualsaandbare known to agree in certain properties and differ in others, and if in additionahas a further property, then the confirmation of the hypothesis thatbalso has this property is greater than its initial confirmation, at least if the weight of the similarities is sufficiently great compared with the weight of the differences.II. The confirmation‐value increases or decreases with the weight of the similarities between the analogues compared with the weight of their differences.III. The confirmation thatbhasacertain property is greater ifahas that property than ifadoes not have it.The Δ— system sastisfles none of these conditions. Carnap and Stegmüller have now, however, presented a new anxiom system for confirmation functions. the — system(Induktive Logik und Wahrscheinlichkeit, 1959, Appendix B), Which is introduced primarily to deal with languages whose primitive predicates fall into families such that each individual can only be qualified by one predicate of each family. They construct a c‐ function which, as well as dealing with a language having two families of such predicates, also depends, unlike the functions in the Δ— system, onsimilaritiesbetween otherwise different individuals. The system is not developed far enough in this Appendix to enable the authors to discuss the confirmation in analogy arguments satisfying conditions I — III above, but it is shown in the present paper that, with a simple generalization of the measure‐function defined by Carnap and Stegmüller, and in the simplest non‐trivial case, condition I — III are all satisfied, indeed a stronger form of condition I is satisfied, in whichno knownsimilarity of the analogues is postulated.Finally it is remarked that Carnap and Stegmüller's method of introducing their Δ— system is extremely arbitrary andad hoc, and an alternative method of introducing is suggested. Bearing in mind the fundamental nature of the argument from analogy in all application of induction to the real world, it is suggesetd that the fundamental inductive inference needing explication is not the inference of‘P1b, from ‘P,1a, but the analogical infeence of‘P2b, from‘P1P2a.P1b, (where‘P, denotes not‐P). It is posinitial confirmation of‘P2b, and the confirmation of‘P2b, given‘P2a” and that the later two confirmation‐values are equivalent to those in the Δ— system. It is then shown that Carnap and Stegmüller's new measure‐function follows from their axiom system together with these postulates. Thus some of the arbitrariness of the — system is removed by gene

ISSN:0012-2017    

DOI:10.1111/j.1746-8361.1963.tb01568.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY