 Like many other English thinkers, Kilvington was a leader in three main disciplines: terminist logic, mathematical physics, and the new, “mathematical” theology. Methods and procedures developed in the first two disciplines were used in the third. The application of the terminist logic and the refutation of the Aristotelian prohibition against metabasis resulted in Kilvington’s broad use of logic and mathematics in all branches of inquiry to gain certain knowledge. Four types of measurements were involved in his research. The predominant form of measurement by limits, i.e., by the beginning and ending of successive or permanent things (incipit/desinit), by the first and last instants of the beginning and ending of continuous processes (de primo et ultimo instanti), and by the intrinsic and extrinsic limits of capacities of passive and active potencies (de maximo et minimo), does not appear to be straightforwardly mathematical, though it raises mathematical considerations insofar as it prescribes measure for natural processes, such as changing the elements, heating, changing the speed of motion, acquiring knowledge, getting better or forming the habit to perform meritorious deeds. The second type of measurement, by latitude of forms, describes processes in which accidental forms are intensified or diminished in terms of the distribution of natural qualities such as heat or whiteness or moral qualities such as love, grace, sin, will, or desire. In his measurement of the intension and remission of forms, Kilvington is interested in determining how the highest degree of a quality can be introduced into a subject already possessing the same quality to a certain degree by undergoing an alteration, and consequently in establishing the possibility of a most intense or diminished degree of, e.g., heat and cold, or virtue and vice. The third type of measurement, the strictly mathematical, employs a new calculus of compounding proportions to measure speed in local motion or speed in the distribution of love. Finally, the fourth type of measurement describes a ‘rule’ permitting the comparison of infinities, treated as infinite sets containing infinite subsets, and determining which of them is equal, lesser, or greater.