This functionary, however, has been thoroughly mystified; and the
      remote source of his defeat lies in the supposition that the
      Minister is a fool, because he has acquired renown as a poet. All
      fools are poets; this the Prefect feels; and he is merely guilty
      of a non distributio medii in thence inferring that all poets are
      fools.”

      “But is this really the poet?” I asked. “There are two brothers,
      I know; and both have attained reputation in letters. The
      Minister I believe has written learnedly on the Differential
      Calculus. He is a mathematician, and no poet.”

      “You are mistaken; I know him well; he is both. As poet and
      mathematician, he would reason well; as mere mathematician, he
      could not have reasoned at all, and thus would have been at the
      mercy of the Prefect.”

      “You surprise me,” I said, “by these opinions, which have been
      contradicted by the voice of the world. You do not mean to set at
      naught the well-digested idea of centuries. The mathematical
      reason has long been regarded as the reason par excellence.”

      “‘Il y a à parièr,’” replied Dupin, quoting from Chamfort, “‘que
      toute idée publique, toute convention reçue est une sottise, car
      elle a convenue au plus grand nombre.’ The mathematicians, I
      grant you, have done their best to promulgate the popular error
      to which you allude, and which is none the less an error for its
      promulgation as truth. With an art worthy a better cause, for
      example, they have insinuated the term ‘analysis’ into
      application to algebra. The French are the originators of this
      particular deception; but if a term is of any importance—if words
      derive any value from applicability—then ‘analysis’ conveys
      ‘algebra’ about as much as, in Latin, ‘ambitus’ implies
      ‘ambition,’ ‘_religio_’ ‘religion,’ or ‘_homines honesti_’ a set
      of _honorable_ men.”

      “You have a quarrel on hand, I see,” said I, “with some of the
      algebraists of Paris; but proceed.”

      “I dispute the availability, and thus the value, of that reason
      which is cultivated in any especial form other than the
      abstractly logical. I dispute, in particular, the reason educed
      by mathematical study. The mathematics are the science of form
      and quantity; mathematical reasoning is merely logic applied to
      observation upon form and quantity. The great error lies in
      supposing that even the truths of what is called pure algebra,
      are abstract or general truths. And this error is so egregious
      that I am confounded at the universality with which it has been
      received. Mathematical axioms are not axioms of general truth. What is true of relation—of form and quantity—is often grossly
      false in regard to morals, for example. In this latter science it
      is very usually untrue that the aggregated parts are equal to the
      whole. In chemistry also the axiom fails. In the consideration of
      motive it fails; for two motives, each of a given value, have
      not, necessarily, a value when united, equal to the sum of their
      values apart. There are numerous other mathematical truths which
      are only truths within the limits of relation. But the
      mathematician argues, from his finite truths, through habit, as
      if they were of an absolutely general applicability—as the world
      indeed imagines them to be. Bryant, in his very learned
      ‘Mythology,’ mentions an analogous source of error, when he says
      that ‘although the Pagan fables are not believed, yet we forget
      ourselves continually, and make inferences from them as existing
      realities.’ With the algebraists, however, who are Pagans
      themselves, the ‘Pagan fables’ are believed, and the inferences
      are made, not so much through lapse of memory, as through an
      unaccountable addling of the brains. In short, I never yet
      encountered the mere mathematician who could be trusted out of
      equal roots, or one who did not clandestinely hold it as a point
      of his faith that x2+px was absolutely and unconditionally equal
      to q. Say to one of these gentlemen, by way of experiment, if you
      please, that you believe occasions may occur where x2+px is not
      altogether equal to q, and, having made him understand what you
      mean, get out of his reach as speedily as convenient, for, beyond
      doubt, he will endeavor to knock you down. “I mean to say,” continued Dupin, while I merely laughed at his
      last observations, “that if the Minister had been no more than a
      mathematician, the Prefect would have been under no necessity of
      giving me this check. I know him, however, as both mathematician
      and poet, and my measures were adapted to his capacity, with
      reference to the circumstances by which he was surrounded. I knew
      him as a courtier, too, and as a bold intriguant. Such a man, I
      considered, could not fail to be aware of the ordinary policial
      modes of action. He could not have failed to anticipate—and
      events have proved that he did not fail to anticipate—the
      waylayings to which he was subjected. He must have foreseen, I
      reflected, the secret investigations of his premises. His
      frequent absences from home at night, which were hailed by the
      Prefect as certain aids to his success, I regarded only as ruses,
      to afford opportunity for thorough search to the police, and thus
      the sooner to impress them with the conviction to which G——, in
      fact, did finally arrive—the conviction that the letter was not
      upon the premises. I felt, also, that the whole train of thought,
      which I was at some pains in detailing to you just now,
      concerning the invariable principle of policial action in
      searches for articles concealed—I felt that this whole train of
      thought would necessarily pass through the mind of the Minister. It would imperatively lead him to despise all the ordinary nooks
      of concealment. He could not, I reflected, be so weak as not to
      see that the most intricate and remote recess of his hotel would
      be as open as his commonest closets to the eyes, to the probes,
      to the gimlets, and to the microscopes of the Prefect. I saw, in
      fine, that he would be driven, as a matter of course, to
      simplicity, if not deliberately induced to it as a matter of
      choice. You will remember, perhaps, how desperately the Prefect
      laughed when I suggested, upon our first interview, that it was
      just possible this mystery troubled him so much on account of its
      being so very self-evident.”

      “Yes,” said I, “I remember his merriment well.