A permissivist framework is developed to include images in the reconstruction of the evidential base and of the theoretical content. The paper uses Newton’s optical theory as a case study to discuss mathematical idealizations and depictions of experiments, together with textual correlates of diagrams. Instead of assuming some specific type of theoretical content, focus is on novel traits that are delineable when studying the carriers of a theory. The framework is developed to trace elliptic and ambiguous message design, and utilizes (...) variegated acceptance as an asset. Newton’s resources allowed for various framing modes and reconstructions, entailing various judgements concerning the theoretical content, the evidence base, and Newton’s use of mathematics. Elliptic presentation of the theory’s proof-structure and ambiguities influenced uptake, contributed to the process of opinion-polarization, and the acceptance/rejection of the theory. The study suggests that the analysed carriers of theoretical content have an argumentative function, and one of their uses is to adjust the burden of proof. (shrink)

The polarity of light and dark in the treatment of the Newtonian spectrum and the inverse spectrum is studied further and the validity of heterogeneity of light and darkness in relation to Goethe’s views is examined. In order to clarify the reality of the “darkness rays”, theexperimentum crucisis re-evaluated. It is shown that the commonly accepted analysis contains assumptions in the choice of the spectrum and background, which mask the inherent dynamic of the spectrum. The relation between colour and wavelength (...) is re-examined with respect to the immutability and specific refrangibility of colour. It is then shown that both these properties are approximations that apply under the specific conditions that have later become standardized in spectroscopy, leading to a consensus regarding the relation of wavelength to colours of one particular spectrum. This consensus has resulted in the study of colour diverging into spectroscopy and colour physiology. As an alternative, the basis of the dichotomy postulated by Müller is studied, leading to the realization that the resolution of this dichotomy was begun by Goethe with the idea of turbidity. A further study shows that turbidity resolves the apparent incompatibility of light and dark. (shrink)