deeply infected by second-order concepts. The latter may typically involve objects and arguments qualified as second or higher order with respect to the former, which nevertheless are of the first-order type when considered as related to the background set universe.

Ernst Cassirer
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Does the equation $L = L1 +\epsilon$ not amount to an underestimation of the historical Leibniz? Is it reasonable to assume that he only invented the calculus, and not analysis? According to Cassirer, the basic concepts of analysis were deeply soaked with philosophy, i.e., for Leibniz mathematical and philosophical concepts were intimately related:[^3]

> Leibniz himself asserted that the new analysis has sprung from the innermost source of philosophy, and he assigned to both regions \[i.e., analysis and philosophy\] the task to confirm and to elucidate each other.[^4] [@Ca02 p. xi]

If L = L1 + epsilon, i.e., if the historical Leibniz was mainly dealing with *calculus*, this may appear hardly compatible with Cassirer’s perspective; see [@MK]. This impression would be, however, a misunderstanding. In order to forestall it, it merits being pointed out that developing the calculus was a great mathematical achievement of philosophical relevance. It is only today that the term *calculus* possesses a connotation 