Heidegger saw science as a derivative activity with respect to other activities of the life-world; the making-present involves the transformation of something ready-to-hand to something present-at-hand and thereby the detachment of scientific entities and observations from the life-world, from human culture and history. In contrast to Dewey, Heidegger holds that the beings studied by the scientist are desiccated. "The botanist's plants are not the flowers of the hedgerow; the 'source' which the geographer establishes for a river is not the 'springhead in the dale'" (100). Far from being world-building, science serves to encourage eradication of experience in the world. Heidegger thus accepts uncritically certain assumptions of the mythic account, including the priority of theory, the detachment of the scientist from scientific entities and observations, and the independence of scientific entities from the cultural and historical context.
Do scientific entities appear, in experimentation, as present-at-hand objects thematized by a particular understanding of Being? No, for three reasons. First, a scientific experiment is a unique event in the world, takes time, has a beginning and end, and must be initiated and carried to completion. Every experiment is equally original, and not a recollection or echo of a past event. Nevertheless, in that unique event, something can appear able to be identified and reidentified as the same; the experiment forges the same phenomenon out of an ever-changing context, not as an externalization of something hidden or as a backwards-looking act of repetition, but as an act that is simultaneously creative and repetitive. In an experiment, something emerges, comes to light; scientific entities come to have a real presence in the world. For the experimenter in the laboratory, ,the "electron" is a real phenomenon, a piece of material ontology involved in casual explanations. And theory has something to do with that experience of sameness, in describing how this particular experience of an experimental object belongs within a particular field of possibilities of experience that are the possibilities of experience of the same object. Moreover, standardized practices can allow such phenomena to appear outside of the laboratory in the life-world where they can be used without theory, in such things as cigarette lighters, thermometers, and microwaves. Science is thus world-building, for it brings things into the life-world that were not there before - not as abstractions, but as real beings. Microwaves are not used abstractively but casually in ovens, radio waves in communication, and so forth.
Second, scientific entities are brought into the world through an artistic process. They are not seen with Cartesian clarity. Phenomena come to show themselves in scientific experimentation often via artistic skill. They have to be wooed, coaxed into existence, and often show up misleadingly or only inadequately; seasoned experimental scientists have troves of stories not only about how they were once almost misled into thinking that they had made great discoveries when actually something simply had been overlooked, but also about how they were misled into attributing conventional explanations to what would turn out, in the hands of others, to be genuinely new and important results. Moreover, some scientific performances are so virtuosic as to be essentially unrepeatable. Demonstration experiments such as those found in science museums - that allow the casual visitor to "repeat" famous experiments in the history of science by flipping switches - are possible only because the praxes have been standardized within a relatively nonhistorical context that is kept constant. The environment of the working laboratory, by contrast, is anything but constant.
Third, scientific entities are historically fragile. When the world changes, new scientific phenomena appear, certain existing scientific phenomena disappear, while most others show themselves in a new light. Ether, phlogiston, and caloric disappeared; will someone say that they were "really" never there at all? That would be to render incoherent the scientific world of the day. Electrons may well turn out to be manifestations of a single kind of entity called a "lepton", and that in turn may be a manifestation of something else; will some future scientist be correct to say that the electron, that fundament of the twentieth century technology never "really" existed?
Scientific phenomena thus are not things rendered present-at-hand through a prior thematization. But neither are they things ready-to-hand for they are thematized in some sense, explored for their own sake, and instead of becoming invisible in the praxis involving them (like t he hammer) become explicitly grasped and are even lingered over.
*Indiana University Press, 1993
[After Post-Modernism Conference. Copyright 1997.]