# Does "having a calculus" refer to a "motive"/"ulterior motive" or "rationale"? **URL:** \ **Category:** Factual Questions\ **Created:** [July 22, 2013, 2:34pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193 "2013-07-22T14:34:28Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![davidmich](https://avatars.discourse-cdn.com/v4/letter/d/e56c9b/32.png) [@davidmich](https://boards.straightdope.com/u/davidmich)\ **Post date:** [July 22, 2013, 2:34pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/1 "2013-07-22T14:34:28Z")
Hi Does “having a calculus” refer to a “motive”/“ulterior motive” or “rationale”? I can’t find any good definition for the term “calculus” used in this non-mathematical sense. Perhaps someone out there can help me with a good definition Thanks davidmich ---
**Author:** ![Morgenstern](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@Morgenstern](https://boards.straightdope.com/u/Morgenstern)\ **Post date:** [July 22, 2013, 2:53pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/2 "2013-07-22T14:53:43Z")
Never heard of that and apparently it’s news to Google too. This question is probably better suited for GQ. Perhaps you can message a mod to move it. ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [July 22, 2013, 2:57pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/3 "2013-07-22T14:57:09Z")
Moved to General Questions from About This Message Board. ---
**Author:** ![Inner\_Stickler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inner_stickler/32/318_2.png) [@Inner\_Stickler](https://boards.straightdope.com/u/Inner_Stickler)\ **Post date:** [July 22, 2013, 3:00pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/4 "2013-07-22T15:00:15Z")
To me, “having a calculus” is neutral and doesn’t imply anything underhanded. ---
**Author:** ![Jragon](https://avatars.discourse-cdn.com/v4/letter/j/e19b73/32.png) [@Jragon](https://boards.straightdope.com/u/Jragon)\ **Post date:** [July 22, 2013, 3:01pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/5 "2013-07-22T15:01:00Z")
I take it as “rationale”, as in “the way I calculate my viewpoint on this subject”. “Altering my calculus” refers to new information necessitating re-evaluation of how you perceive the subject. ---
**Author:** ![moriah](https://avatars.discourse-cdn.com/v4/letter/m/b2d939/32.png) [@moriah](https://boards.straightdope.com/u/moriah)\ **Post date:** [July 22, 2013, 3:15pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/6 "2013-07-22T15:15:05Z")
> [@davidmich](#): > > Hi > > Does “having a calculus” refer to a “motive”/“ulterior motive” or “rationale”? > I can’t find any good definition for the term “calculus” used in this non-mathematical sense. Perhaps someone out there can help me with a good definition > Thanks > davidmich [Calculus can simply mean calculations.](http://education.yahoo.com/reference/dictionary/entry/calculus) And by metaphorical extension, having looked at all the figures and made appropriate plans. Thus, ‘having a calculus’ can mean simply ‘have a plan that has been meticulously figured out.’ ---
**Author:** ![Svejk\_1](https://avatars.discourse-cdn.com/v4/letter/s/ea666f/32.png) [@Svejk\_1](https://boards.straightdope.com/u/Svejk_1)\ **Post date:** [July 22, 2013, 4:03pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/7 "2013-07-22T16:03:11Z")
The term “voting calculus” is commonly used in political science when referring to the ways voters make up their minds, the things they take into account when making their decision. It is a neutral, descriptive term that does not necessitate judgments on the nature of voters’ criteria, whatever they may be. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [July 22, 2013, 4:57pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/8 "2013-07-22T16:57:27Z")
Never heard it in that sense. To me, a non-mathematical “having a calculus” means you have a kidney stone\*, and my condolences. \*or other bodily concretion, but “kidney stone” is the most common usage > **[Kidney stone disease](https://en.wikipedia.org/wiki/Kidney_calculus)** > > Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine stream. A small stone may pass without causing symptoms. If a stone grows to more than 5 millimeters (0.2 inches), it can cause blockage of the ureter, resulting in sharp and severe pain in the lower back or abdomen. A stone may also result in Most stones ... > **[Calculus (medicine)](https://en.wikipedia.org/wiki/Calculus_(medicine))** > > A calculus (plural calculi), often called a stone, is a concretion of material, usually mineral salts, that forms in an organ or duct of the body. Formation of calculi is known as lithiasis (/ˌlɪˈθaɪəsɪs/). Stones can cause a number of medical conditions. > Some common principles (below) apply to stones at any location, but for specifics see the particular stone type in question. > Calculi are not to be confused with gastroliths. > Calculi are usually asymptomatic, and large calculi may have require... ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [July 23, 2013, 2:39am UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/9 "2013-07-23T02:39:14Z")
It would help if you quote the passage in which this term is used. I’ve seen things like it before. It’s a pretty sloppy expression, I feel. It’s used to mean “have a means to decide what to do in a given situation.” The original idea was that one might need to do calculations to decide what to do in a given situation. It’s usually used though not for mathematical calculations about what to do but for what issues one thinks about in making a decision. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [July 23, 2013, 3:36am UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/10 "2013-07-23T03:36:17Z")
Seems to me to mean “scheme”, possibly neutral, possibly underhanded… I.e. a person has weighed the consequences of a course of action and figures they have a path which achieves their desired result. ---
**Author:** ![rowrrbazzle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rowrrbazzle/32/414_2.png) [@rowrrbazzle](https://boards.straightdope.com/u/rowrrbazzle)\ **Post date:** [July 23, 2013, 4:11am UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/11 "2013-07-23T04:11:20Z")
Googling "the calculus of " gets you 3 non-mathematical uses on the first page: the calculus of consent / love / friendship. ---
**Author:** ![davidmich](https://avatars.discourse-cdn.com/v4/letter/d/e56c9b/32.png) [@davidmich](https://boards.straightdope.com/u/davidmich)\ **Post date:** [July 23, 2013, 9:42am UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/12 "2013-07-23T09:42:40Z")
Thank you all for your helpful replies. I have come across the term “calculus” in examples such as 1.The killer calculus of President Obama’s re-election chances. Let’s substitute the word “calculus” for “scheme” or “plan”. Ok. Makes sense. 2. Many riders tussle daily with the timeless question: local or express? But for the denizens of the N, R or Q trains, traveling uptown through Midtown, the calculus is a bit more complicated. Let’s substitute the word “calculus” for “decision-making” or “planning”. Makes sense. So calculus in the non-mathematical sense appears top mean “scheme” or “plan” or “decision-making”/“planning”. Thanks everyone. davidmich ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [July 23, 2013, 11:44am UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/13 "2013-07-23T11:44:47Z")
I would say that “the killer calculus of President Obama’s re-election chances” means “the difficult calculations that one would needs to make to decide if Obama will be re-elected.” (I assume this sentence is quoted from something written before the election last year.) I would say that “but for the denizens of the N, R or Q trains, traveling uptown through Midtown, the calculus is a bit more complicated” means that trying to calculate what is the fastest way to travel uptown if you’re going through Midtown Manhattan by subway is will be quite complicated. ---
**Author:** ![davidmich](https://avatars.discourse-cdn.com/v4/letter/d/e56c9b/32.png) [@davidmich](https://boards.straightdope.com/u/davidmich)\ **Post date:** [July 23, 2013, 12:01pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/14 "2013-07-23T12:01:18Z")
Thank you for that helpful reply Wendell Wagner. Sticking with “calculation” as a definition of “calculus” (as the above example use the word) makes sense. Good point. Thank you for that helpful reply Wendell Wagner. davidmich ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [July 23, 2013, 1:23pm UTC](https://boards.straightdope.com/t/does-having-a-calculus-refer-to-a-motive-ulterior-motive-or-rationale/664193/15 "2013-07-23T13:23:41Z")
Yes, in those cases it is certainly that "calculus’ is being used to mean “method of calculation”. As a further example, there are two mathematical formalisms in optics commonly used to manipulate quantities associated with polarized light. Both are really simply form of matrix multiplication, and have nothing to do with integration or differentiation (the two basic operations in what is commonly called “calculus”), but these methods are called the “Jone Calculus” and the “Mueller calculus”. In both cases, “calculus” is clearly just “method of calculation”.