Should We Believe in Cells, or Just Remain Agnostic about Them? A Critical Analysis Through Bas van Fraassen’s Lenses.

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.