Metaphor is the spice of life. If youhave a problem with using the word optics then you have a problemwith how language works, adapts, and forms new communication.
There is inertia from physics, and there is 'human inertia' like our federal govt.
A calculus is any form of analysis. Forexample Hamas is adhering to a failed political calculus.
'The Calculus' generally refers to theNewton-Leibnitz notation.
http://www.thefreedictionary.com/calculus
n. pl. cal·cu·li (-l) orcal·cu·lus·es
1. Pathology An abnormal concretion inthe body, usually formed of mineral salts and found in thegallbladder, kidney, or urinary bladder, for example.
2. Dentistry See tartar.
3. Mathematics
a. The branch of mathematics thatdeals with limits and the differentiation and integration offunctions of one or more variables.
b. A method of analysis or calculationusing a special symbolic notation.
c. The combined mathematics ofdifferential calculus and integral calculus.
4. A system or method of calculation:"[a] dazzling grasp of the nation's byzantine budget calculus"(David M. Alpern).