Dumbleton’s masterwork is his Summa Logicae et Philosophiae Naturalis (Summary of Logic and Natural Philosophy), likely to have been composed just before the time of his death.
[3]: 253 The fact that no extant copy of Dumbleton's Summa Logicae et Philosophiae Naturalis is complete (nor edited) leads one to wonder if his death (ca.
Though there was a considerable reverence for Platonism in Oxford during the fourteenth century, the rebirth of Aristotelianism held sway in the higher Parisian learning circuits.
A strong Aristotelian appreciation is felt in the remaining sections, since the majority of the work is dedicated to commenting on the first eight chapters of Aristotle's Physics, and his treatises On Generation and Corruption & On the Soul.
[4] Though the idea of molecules was not theorized at this time, Dumbleton’s speculation helped to tame the view that bodies have infinitely divisible parts.
He gave a proof of the mean speed theorem stating that "the latitude of a uniformly difform movement corresponds to the degree of the midpoint" and used this method to study the quantitative decrease in intensity of illumination, stating that it was not linearly proportional to the distance, but was unable to expose the Inverse-square law, which was postponed nearly 250 years until its discovery by Johannes Kepler in 1604.
Regardless of whether they opted against empirical investigation for theological reasons or simply because the debut of the scientific method was not ready to be revealed, one ought to regard John of Dumbleton and his contemporaries as exemplary pioneers in mathematics, physics, and logical discourse.