Model organisms are at the centre of progress in biology but attributing them an excessive representational power and concentrating on a limited group of them, although efficient for research, can have negative consequences, mainly of epistemic nature. Here, I argue that model organisms are exploratory models with a perspectival modelling function, and that a deflated representational power is needed for their proper use. In support of this argument, I will analyse developmental biology as a case study. Firstly, I show that (...) model organisms in developmental biology are not selected because of their representational capabilities, but mainly based on practical criteria. Secondly, I defend that the epistemic organization of developmental biology around questions fosters exploration and perspectival modelling and I propose that developmental biology is a ‘model organism situated knowledge’. Lastly, I use the study of the mechanisms of cell fate acquisition during early embryonic development in _C. elegans_ and mice as a case study to illustrate how a plurality of model organisms allows exploration and perspectival modelling. The use of model organisms for exploration and perspectival modelling, with a limited representational power, should allow more adequate inferences about human embryonic development and encourage the introduction of more model organisms for a comprehensive navigation of the space of possibilities. (shrink)

For constructive empiricism, being observable or unobservable is defining for deciding about the empirical adequacy and epistemic value of theory components. The classification of microscopic images has been particularly debated. van Fraassen initially classified microscope images as unobservable and then as mere images, like rainbows. Afterwards, he claimed it is not irrational to maintain neutrality about their classification and left them in some kind of limbo between being images of something real or being mere images. Here, I provide an argument (...) to classify microscopic images of cells as copy-qualified images. The argument is described in general terms to sustain that any unobservable entity that is derived from observable self-dividing entities and looks similar to the observable entity when detected under the microscope, corresponds to a copy-qualified image of something real. Because of the existence in nature of large observable cells that fulfil these properties, I conclude that microscopic images of cells are images of something real. This determines their empirical adequacy and epistemic value, making them hard-core and stable components of biological theories. The argument described provides a strategy to develop a more grained classification of what is observable and unobservable with the consequent implications for theory development. (shrink)