J. Kirkman
Department of English
University of Wales Institute of Science and Technology
Cardiff

        Excessive use of passive verbs creates scientific writing that is cumbersome and indigestible to read. Greater use of active verbs, with a judicious mixture of personal and impersonal constructions, produces writing that is more readable yet retains the necessary clarity of meaning and propriety of tone for scientific papers.
        It is surely axiomatic that the aim of scientific writing is to transmit information accurately, quickly and economically from one person to another. Then why do so many scientists make their papers heavily unreadable? Obviously, the subject matter of the papers is sometimes complex and conceptually difficult; but frequently the ‘unreadability’ stems mainly from use of a style which makes the reader’s task much heavier than it need be.

Scientists as performers
        One feature that contributes greatly to the ‘heaviness’ of scientific writing is excessive use of verbs in the passive voice. This produces an effect that is cumbersome, roundabout, and often – if you notice the double meanings – comic! Have you ever noticed how much time scientists spend performing:

and conducting:

and having experiences:

They are great carriers, too (and it is interesting that they invariably carry things out, rarely in, or up, or over or through):

        Expressions such as ‘was performed’, ‘were conducted’, ‘were experienced’, ‘were carried out’, ‘was achieved’, ‘was shown’, ‘were effected’, ‘were observed’, ‘resulted’ and ‘occurred’ are desperately overworked in scientific writing because scientists are reluctant to write directly and personally. Somehow, a legend has grown up that a personal, direct account of scientific work is not acceptable in scientific papers. So the writer who wants to say ‘We calculated the yield and found that’ pauses, and contorts his thought into the clumsier expressions ‘Calculations of the yield were performed which revealed that’. He converts ‘which gave one of the strongest wiremarks we have ever seen’ into ‘which gave one of the strongest wiremarks experienced’. The simple statement ‘We measured the electron densities in argon afterglows’ becomes ‘Measurements of electron densities in argon afterglows were carried out’.

Change of emphasis with the passive
        If we accept the premise that all scientific papers must be passive and impersonal, inevitably we find ourselves tempted to use these ‘carrier verbs’. If we will not write:

we can write in simple passive form:

But it is tempting to take a further step and expand these statements to:

        In taking this extra step we not only change the verb forms from active to passive, but also introduce colourless ‘general purpose’ verbs ‘carrying’ abstract nouns. We no longer sample, remove and inspect; we achieve, effect and carry out. And the focus of our statements is no longer on ions, the coating or the burners; it moves to the vaguer abstractions sampling, removal and inspections.
        Undoubtedly, there are many occasions when we want to focus on sampling rather than on ions, or on inspections rather than on burners. In such circumstances, the use of a passive construction is a valuable way of moving the emphasis of a sentence. My aim is not to condemn all use of passive constructions: it is to stress the pernicious effect of using passive constructions as the rule rather than as the exception. To do so is virtually to guarantee that a paper will become ponderously roundabout, abstract and heavy to read.

Should we ban personal pronouns?
        If a scientist is asked to justify his insistence on impersonal, passive style for scientific papers, he usually maintains that personal pronouns reflect an immodest, ‘subjective’ and therefore unacceptable intrusion of individual judgement into what should be a detached, impersonal account of scientific fact. But curiously, this ‘intrusion’ seems to be objectionable only when he writes about his work. In his laboratory, he will talk happily in comfortable, direct terms:

It is only when he comes to write his reports that he feels constrained to retire behind impersonal constructions:

        The ban on personal pronouns is based, it seems, not on an insistence that the recounting of scientific facts must be anonymous and ‘objective’; it is based on a feeling that the personal, active phrasing acceptable in serious discussion is not acceptable in serious writing. I know of no good reason why this should be so.

The style we should strive for
        In advocating the use in writing of the personal, active phrasing of serious discussion, I am not advocating use of the casual, inexplicit shorthand of person-to-person chitchat. I am not advocating that the account should be overpersonalized, sensationalized or trivialized. Overindulgence in personal constructions is just as distorting as nonindulgence: to sound like the great I Didit is as bad as to pretend you were not involved at all. And I am not suggesting that the scientific content should be distorted in any way. I am advocating that writers should write naturally and economically, without affectation of a special ‘scientific style’. They should come as close as possible to the natural mixture of constructions and the natural balance and rhythms of comfortable everyday speech.
        One other point needs emphasis here. My advice is often misrepresented as encouragement to writers to claim credit for work they did not do themselves. That would be true if I advocated that all impersonal, passive constructions should be replaced by ‘I’ or ‘we’. I make no such suggestion. If much work has been done on a project by someone other than the writer or the writer's group, then it is entirely appropriate to write ‘Much work has been done’ or ‘In many experimental programmes it has been found that’, with or without attribution to a particular agent. I advocate simply that writers should make statements active wherever possible. For example, ‘Installation of a noise barrier has been carried out by Smith and Jones’ should be converted to ‘Smith and Jones have installed a noise barrier’. And in particular, where writers have been personally involved in some work, they should not use cumbersome passive constructions simply to avoid saying ‘I’ or ‘we’.
        An example chosen at random from a physics research journal, and how it might have been written using active verbs, more personal constructions and simpler sentence structure. Which do you find more readable?
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Original passage
        The history of negative ion current has in several afterglow studies (eg Fite and Rutherford 1964, Smith and Plumb 1973b) been observed to exhibit a rather surprising, yet reproducible, form. An initial period during which negative ion wall current is not observed is followed by rapid and unpredictable onset of current, which cannot be reconciled with the expected variation of negative ion density in the body of tile plasma, although measurements of the negative ion density have not been carried out. This phenomenon has been attributed to the ambipolar field within the plasmas which initially inhibits the flow of negative ions to the walls until the electron component of the plasma decreases, by diffusion, to near zero with the subsequent collapse of the ambipolar field. A positive ion/negative ion plasma is thus established when the negative ions are no longer ‘trapped’ within the plasma and are able to diffuse towards the walls (Puckett and Lineberger 1970, Kregel 1970). In order to further elucidate this ‘trapping’ phenomenon, it is clearly necessary to probe within the plasma volume and to make simultaneous wall current observations. To this end measurements were made concerning the temporal and spatial variations of the space charge fields . . .

The active, personal approach
        Several afterglow studies (eg Fite and Rutherford 1964, Smith and Plumb 1973b) have produced surprising yet reproducible histories of negative ion wall current. At first there is no current: then, onset of current is rapid and unpredictable. This cannot be reconciled with the expected variation of negative ion density in the body of the plasma. However, that density has not been measured. Puckett and Lineberger (1970) and Kregel (1970) have suggested that the ambipolar field within the plasmas prevents the flow of negative ions to the walls until the electron component of the plasma decreases (by diffusion) to near zero. This collapses the ambipolar field, and creates a positive ion/negative ion plasma in which the negative ions are no longer ‘trapped’. They are therefore able to diffuse towards the walls. To elucidate this ‘trapping’, we thought it necessary to probe within the plasma volume, simultaneously notice wall current. So, we measured the temporal and spatial variations in the space charge fields . . . ______________________________________________________________________________
The disadvantage of insistence on passives
        The cumbersome quality of much of the phrasing used to avoid personal pronouns is a major disadvantage of insistence on impersonal, passive, constructions as the main mode of expression in scientific papers. My earlier examples have already illustrated this. The writers of those examples could have written passively without the clumsy circumlocutions. But they did not. The impersonal, passive habit of thought exerts a pernicious, inflating influence on scientific writers, as is emphasized by these examples:

        Even more damaging is the confusion that can be caused for readers by impersonal, passive constructions. The reader's difficulty can be caused simply by uncertainty about who is responsible for assertions or decisions:

        Commonly, too, impersonal constructions mask changes of theme or location in a discussion. The following extract from an introduction to a paper seems to be entirely devoted to describing previous work by John Brown:
        ‘The following investigation was begun as a result of recommendations by John Brown in the report ‘Measurements on baseplate profiles’. His report noted that . . . the top edge suffered no appreciable dimensional change, even after several years’ service. However, new baseplates often were outside specified tolerances in the random sample tested. It was decided that the measurements should be made on a freestanding atmospheric rig, using air as the working fluid. Six plates were to be tested under varying . . .’
        In fact, the penultimate sentence begins to describe decisions taken by the report-writer in designing his own work. The transition could have been completely clear if he had written ‘I decided that I would make my measurements’. There would have been no lack of humility or distortion of scientific fact in this. The gain in clarity would have been considerable.

The need for proper scientific humility
        The need to preserve ‘proper’ scientific detachment and humility is often stressed by scientists who will not accept personal, active writing in scientific papers. They contend that readers of scientific papers are interested primarily in the scientific facts, not in who established them: the use of ‘I’ or ‘we’ is an unwarranted, immodest introduction of a specific agent into the account.
        I have argued already that the clear specification of an agent is frequently essential to the reader’s understanding of an account. I would contest, too, the implication that the use of an expression such as ‘Our results showed’ or ‘I assumed that the pressure would remain’ necessarily strikes readers as immodest. Much depends on the tone created by the wording of the rest of the paper. But more important, perhaps, than these points is that many of the constructions used to evade the use of personal pronouns are more obtrusive than the pronouns themselves; and they do nothing to remove the element of subjective judgment.
Which seem more artificial and obtrusive - the original quotations below, or the revisions offered?

And can the following impersonal, passive constructions be described in any sense as ‘detached’ or ‘objective’?

Casual change of meaning
        A fourth serious disadvantage of insistence on impersonal, passive constructions is that it often leads writers to change what they meant to say. The writer who thinks to himself ‘I do not accept the idea’ feels obliged to find another wording. He settles for ‘One cannot accept tile idea’ or ‘The idea cannot be accepted’. In so doing, he changes what he is saying. These three statements do not say the same thing: they are not lightly interchangeable. Most scientist would be horrified at the thought of unrecognized inaccuracy in their experimental work; yet an astonishing number cheerfully ignore vaguenesses and approximations of meaning as they choose words and phrases for their writing.

The tactics of effective writing
        Of course, there is much more to effective writing than just careful choice of verbs and personal constructions. Effective writing calls for a choice of tactics that will achieve a given aim for a given audience in a given context. It involves clear recognition of the diplomatic and social constraints surrounding the writing task (including the whims and prejudices of tutors, supervisors and bosses?). It involves thoughtful selection and arrangement of information, careful organization and layout, skilful integration of verbal and nonverbal presentation techniques, and shrewd choice of style. Choice of style involves though about paragraph and sentence structure, vocabulary, phrasing and idiom, and punctuation as well as careful selection of person and voice.
        Nevertheless, the way in which we encourage young writers to think about choice of verbs and constructions is of outstanding significance, because it goes a long way towards establishing their overall ‘mental set’. Are they to think as directly and positively as possible, or are they to approach every statement in a roundabout, noncommittal (self-protective?) way? Certainly, there are times when we have to write diplomatically. Certainly, there are may contexts and topics which do not naturally call up personal constructions: But in most scientific papers and reports, we are concerned to be as direct, explicit and economical as we can. In those circumstances we should write in a natural, comfortable mixture of personal and impersonal constructions, using active verbs wherever possible, and reducing to a minimum the influence of that pernicious passive voice.

The effects of inflation