The first observations of dislocations by TEM were published in 1956. Since then the technique has been developed into an indispensable tool for the materials scientist, not only for the characterization of the extended defect structure of materials, but also for the elucidation of the mechanisms controlling their properties. To mark the 50th anniversary of the original work, this Special Issue consists of reprints of the three original papers and some 22 current state-of-the-art articles, which provide a snapshot of the (...) tremendous power and versatility of the technique at the present time. It is also hoped that this collection of papers from different areas of application and including different techniques might stimulate some cross-fertilization. In this introduction, we comment briefly on the context in which the original work was performed, trace some of the important developments that have taken place in the intervening period and identify some of the outstanding problems. (shrink)

This article briefly presents and characterizes a relatively young (nineteen-nineties) trend in methodology, the theory of science – and philosophy, called “the new experimentalism”. The fundamental problem is determined by the question about the value of the new experimentalism and experimental grounds of scientific knowledge in empirical sciences. In the first part of the article, the previous (old) experimentalism is presented. First of all, the history of the experimental method is outlined and the definitions of experiment, object, phenomenon, and of (...) the carried out and analyzed observation are provided. It is shown why the main proposition of experimentalists – “determining a fact based on sensory experience” is fallacious. The second part describes the way in which the representatives of the new experimentalism try to identify and characterize those factors of an experiment that guarantee the objectivity of its result; demonstrate that results are not only determined by psychological, historical, sociological or economic factors but also that they exist in nature as real objects and events. A correct and reliable analysis of the experiment and its results may – according to the new experimentalists – contribute to this conclusion. Therefore, the important role and value of the experimental foundation of social activity in general, and in particular, for the natural sciences, is rightly noted. (shrink)