Bill Long 11/10/04
Reframing a Definition
Hysteresis has nothing to do with hysteria. The latter, as most know, is derived from the Greek hystera, meaning womb. Feminist and other scholars have gleefully pointed out the obvious patriarchal assumptions behind the root meaning of hysterical as associated with "womblike" behavior. But the root of hysteresis lies elsewhere: in the word hysteros, translated "late," or the verb hystereein, meaning "to be behind or come late." Actually, the English word hysteresis is a transliteration of the Greek word meaning deficiency.
Hysteresis has had two senses in English usage since its first appearance in 1881. First, in the field of magnetism, it refers to the phenomenon by which changes in a property (such as magnetization) "lag behind" changes in a magnetizing force on which they depend. That is, the charged entity retains part of the magnetic charge even after being taken away from the magnetic source. Second, it has a more general meaning, attested since the mid-twentieth century, of "retardation of recovery from an elastic deformation after stress is removed." This essay will focus on the magnetic "field," so to speak, and then broaden the definition for humanistic inquiry.
An Electromagnetic Primer
Iron is not the only but it is the most familiar element exhibiting the characteristic of ferromagnetism, the principle of magnetic attraction. The technical process of how electrons "line up" in various "domains" of the ferromagnetic substance is fascinating but beyond our scope. Suffice it to say that attraction happens. Ferromagnets tend to stay magnetized to some extent after the external magnetic field is removed. But, the ferromagnetic material will not "relax" back to its original or zero magnetization simply by having the charge taken away. It must be driven back to zero by an alternating or reverse electric field.
This "deficiency" or "lack" in returning to zero without an alternating force is called hysteresis. The amount by which it "remains" above the "zero" level after the magnetic charge is removed is called the remanence, and the process by which it returns to "zero" is called coercivity. Once an alternating force is applied, and the magnetic charge disappears, one can map out a hysteresis loop which traces both the "rise" and "fall" of the ferromagnetic object's magnetic charge. I considered giving a picture of the loop here, but if imagine a loop real hard you won't be too far off. There are formulas for calculating the precise curve that such an object will follow when charge is removed and an alternating charge is imposed, but I know you believe me, and I know you hope I don't introduce those forumulas (mathematicians say "formulae" with a sniff) here.
This account of hysteresis and its loop emphasizes the "deficiency" of the object. It is defective in that there is a "lag time" between the change of the agent and the change in the magnetized object. One almost begins to hear a slight allegation of moral deficiency in the object for "lagging" behind. In addition, if we combine this with the more modern definition of hysteresis as the retardation of recovery of orignal shape after an elastic deformation, we again have the concept of lag or slowness or deficiency. It just seems that the hysteretical (to coin a new word) object just can't adjust very quickly to new phenomena.
It is like the popular characterization of older people--just cannot quickly adjust to new realities. Or, one could use the word pejoratively to refer to a woman who gave birth and is slow to shed the pregnancy pounds: "She is just a hysteretical female (no, this is not President Bush trying to pronounce hysterical) who has not yet recovered from the 'elastic deformation' of pregnancy." Guffaw. Guffaw. Chortle.
But precisely at this moment comes the opportunity to construe hysteresis more positively, even virtuously, and some of the definitions online and in other dictionaries give us an indication of how to do this. In this construal hysteresis is characteristic of a system "whose states depend on their immediate history" or, in language of the OED, "any dependence of the value of a property on the past history of the system to which it pertains." That is, an entity demonstrating hysteresis is one that remembers its immediate past, one that is faithful to its magnetic history.
Reflecting on Hysteresis
Just as I often characterize the learning process of older adults as not "slower" but "deeper" (i.e., it takes them more time to get through a page of text because they have the life experience to critically analyze and weigh every sentence, while young and eager readers breezily pass over thoughts of deepest consequence with not a glimmer of recognition or interest), so why not construe hysteresis as a kind of fidelity to lived life and an unwillingness or slowness to change not because of some kind of "lack" or "deficiency," but perhaps for good analytical reasons.
Of course, the original signification of the term, as well as contemporary usage, is tied to its scientific/electromagnetic "field." But why so limit the word? I propose we see it as a term of fidelity to one's past, and then "fill in" the term with a variety of reasons why one might so act. I would dare say that if you did this you would never look at iron filings the same again.
Copyright © 2004-2010 William R. Long