Nucleation and motion of kink pairs on partial dislocations are examined by elasticity theory for materials with a high Peierls stress. Two approaches are used: one considers the change in average stacking-fault energy due to alloying elements and the other considers the change in local SFE due to a nearby solute atom. Both approaches highlight the role of SFE on kink nucleation, propagation and annihilation and both furnish strain rate as a function of stress, temperature and SFE. Model predictions are (...) compared with yield stress data for two systems: firstly, an intermetallic, MoSi 2 , which softens for alloying elements that decrease the SFE and hardens for Re additions that increase the SFE; secondly, a ceramic oxide, MgO-Al 2 O 3 spinel, which softens with increasing addition of excess alumina and at the same time exhibits a decrease in SFE. The average SFE approach agrees qualitatively with the data while quantitative agreement is obtained with the local SFE approach. The possibility is considered that the model applies to other materials, such as TiAl, HfV 2 and Fe 3 Al, which show softening with certain alloying additions. One requirement is that the dislocations are dissociated more than a few atomic distances; otherwise kink nucleation occurs on the perfect dislocation . Hence the model does not apply to materials such as bcc metals which only have a core dissociation. Normal hardening effects of solutes from size and modulus misfits are additive with any softening effects from a decrease in SFE and so may mask the latter, as occurs for W additions to MoSi 2. (shrink)

Hare questions the claim made by modern intuitionists and deontologists that Kant is their ally against utilitarianism. The core of the chapter is a discussion of Kant's Categorial Imperative, which is shown to be compatible, in its various formulations, with utilitarianism. Conspicuously anti‐utilitarian elements of Kantian ethics, Hare argues, are based on principles extrinsic to, and sometimes incompatible with, Kant's moral theory. In answering possible objections to his interpretation, Hare firstly distinguishes pure from applied ethics, which includes an important distinction (...) between Kant's notions of Wille and Willkür; and, secondly, he argues that Kant can be understood as a consequentialist. (shrink)

Plato can claim a preeminent place in the philosophy of education, for two reasons at least. The first is that he started the subject; the second is that he expressed with a force which has not since been surpassed a particular, seemingly authoritarian, view about it. Any liberal has to come to grips with this view, for which ‘Platonism’ is still the most appropriate name; and the first step is to determine more exactly what, in essence, the view is. This (...) paper will not be concerned with the close examination of Plato’s text; that must be left for a book about his moral philosophy that I am working on. I shall say nothing about the quaint details of the educational curriculum in the Republic or the Laws, which have distracted the attention of some commentators from more fundamental problems. What I aim to discuss is the question ‘Can virtue be taught?’, with which Plato introduces the subject in the Meno—the question which more than any other provides the incentive for his entire philosophical enterprise. (shrink)

Монография предназначена для преподавателей вузов, соискателей ученых степеней и студентов.

In the by now well known talks he gave at Princeton, Saul Kripke claimed that “[t]heoretical identities … are generally identities involving two rigid designators and therefore are examples of the necessary a posteriori.” 253-355; A rigid designator is an expression that designates the same object in all possible worlds when it is used. So Kripke is claiming that ‘Water is H20’ and ‘Heat is the motion of molecules’ are generally identities involving expressions like ‘water’ and ‘the motion of molecules’ (...) which designate the same objects in all possible worlds. If the identity statement is true, both sides designate the same object rigidly, i.e., in all possible worlds, and therefore the statement is necessarily true. On the other hand, whether it is true is determined ultimately by appeal to experience. It follows that if true, the identity is necessary a posteriori. (shrink)

In this chapter, conceived originally as the introduction to chapters 3 to 7, Hare shows how philosophical questions arise from the consideration of practical moral problems, such as war and euthanasia. The main task of moral philosophy, Hare argues, is to study the logical form of moral arguments and, in particular, the logical properties of moral words, such as ‘ought’, ‘right’, and ‘good’. All argument, including moral argument, depends on logic, and logical validity depends on the meaning of words. The (...) investigation of the meaning of the words and concepts, and thus the logic, employed in moral and other value judgements is, according to Hare, the distinctive contribution of the moral philosopher to the discussion of substantive moral questions. (shrink)

The thesis of Emotivism, a species of non‐descriptivism, is that there is more to the meaning of moral statements than syntax and truth conditions; in particular, moral statements have an expressive, and a causative aspect. Drawing upon J. L. Austin's distinction between illocutionary and perlocutionary acts, Hare argues that emotivists try to explain the meaning of moral statements, which they assimilate to imperatives, in terms of their perlocutionary effect. The difficulty with this is that, firstly, the emotivists hold a false (...) theory of imperatives, and secondly, perlocutionary effect cannot explain meaning. Furthermore, emotivists deny the possibility of rational moral argument, and therefore embrace irrationalism. Towards the end of this chapter, Hare identifies six essential features of moral language, and its logic, that must be recognized and accounted for by an adequate moral theory: Neutrality, Practicality, Incompatibility, Logicality, Arguability, and Conciliation. (shrink)