Wednesday, November 11, 2015

Cogito Ergo Sum.

Two persons are credited with the quotes below. One is very well-known among economists -- amateurs and professionals, alike -- the other is better-known among philosophers and logicians.

Person A is quoted variously as saying:
"I don't need algebra, I can think."
or, in an alternative version:
"I never learned math, so I had to think."
Person B:
"Few persons care to study logic, because everybody conceives himself to be proficient enough in the art of reasoning already. But I observe that this satisfaction is limited to one's own ratiocination, and does not extend to that of other men."

A little quiz (no credits given).

Although it's safe to assume the authors of those quotes never learned of each other -- on top, one quote is decades older than the other two -- they could have been exchanging barbs. Both are witty, there's no doubt about it: one in a more aggressive way, the other in a deeply ironic vein.

One author wants to project bravado; the other, caution. One may appeal to the humble; the other, to the self-satisfied.

First question: On those accounts, which of these quotes seem wiser to you, dear reader?

One of the two people mentioned above was Joan Robinson, who needs little introduction; the other was Charles S. Peirce, who may need some introduction.

Second question: Who is Person A, and who, Person B?

You better pick carefully, because these quotes may reflect deep differences in the way people see society.


The exact reference for the second quote, together with the answer to the second question, will be given, as un update to this post, in two days' time.


14-11-2015. As promised, the second quote comes from:

Peirce, Charles S. The Fixation of Belief. Popular Science Monthly, no. 12 (November 1877), pp. 1-15. <>

The answer to the second question is: Joan Robinson is Person A; Person B is Charles S. Peirce.

Recently Ann Pettifor has written about remarkable female economists; the second version of Person A's quote comes from Pettifor's post:

On brilliant, neglected women economists – for Woman’s Hour.

Invited by the BBC, together with fellow guest Anne McElvoy (of The Economist), Pettifor produced a list of women who've made remarkable contributions to economics (Victoria Chick, Susan Strange, Cheryl Payer, Yves Smith, Mariana Mazzucato, and Joan Robinson); McElvoy nominated Octavia Hill, "the Victorian reformer that campaigned for decent housing for the poor".

Sadly -- and deeply ironic -- Rosa Luxemburg (and a host of labour activists, like Mother Jones), whose contributions ranged from political and labour activism to theoretical economics, and whose life was cut short by the savagery of the Freikorps and the German Social Democracy, was not mentioned.


  1. I know the answer, at least as to attribution.

    As to which is wiser, I don't think the question is correct. Both are essentially saying the same thing: "intuition" and verbal reasoning and mathematical reasoning are in a dialectical relationship. I know people who have strong intuition, but have a hard time communicating their ideas -- and miss some subtle implications -- because they are bad at math. And I know people who are good at math but have a difficult time seeing the obvious implications and limitations of their models.

    I think both modes of reasoning are valuable, and when working together, yield more than both alone.

  2. Thanks for the comment, Larry.

    "As to which is wiser, I don't think the question is correct. Both are essentially saying the same thing".

    That's a matter of interpretation, I suppose.

    I certainly agree with you in that both are speaking about "intuition", but -- and here I disagree -- at least in my reading one is warning against reliance on intuition and recommending the use of formal methods, while the other takes evident pride on relying on intuition and in disdaining formal methods.

    Incidentally, if I am mistaken on that, at least I'm in good company: others seem to share my interpretation. Ann Pettifor, for instance, has just written a highly laudatory comment on Person A and she made a point of adding this:
    Person A "had avoided mathematical modeling like the plague. She once famously said: 'I never learned math, so I had to think'."
    (Which, btw, is precisely what motivated my post: the idea that formal methods are not only unnecessary, but even counterproductive and outright harmful)

    Nor would Person A be alone in finding something intrinsically inappropriate, but difficult to express, in formal methods as tool for economic analysis. Among modern Keynesians, Tony Lawson is well-known for that. Some fashionable internet PoMo PoKers are another example (although perhaps one should not take them too seriously).

    Most Austrians are at least as opposed to the use of formal methods (the HET website cites this negative as one of their fundamental methodological premises).

    As for the rest of your comment, personally, I believe -- as I think you do -- that both things are complementary, but one should not take that opinion for granted. That would be a serious mistake.


  3. The chief value I see in formal models is as tools of communication. By necessity, they expose their assumptions. One can, of course, choose not to examine the assumptions, or be ignorant of their interpretation, but to the person who can think and do math, I think there is no clearer way to communicate.