Slippery Slope Euthanasia Essay

Critics of euthanasia sometimes claim that legalizing any form of the practice will lead to a slippery slope effect, resulting eventually in non-voluntary or even involuntary euthanasia. The slippery slope argument has been present in the euthanasia debate since at least the 1930s.[1]

Lawyer Eugene Volokh argued in his article The Mechanism of the Slippery Slope that judicial logic could eventually lead to a gradual break in the legal restrictions for euthanasia,[2] while medical oncologist and palliative care specialist Jan Bernheim believes the law can provide safeguards against slippery-slope effects, saying that the grievances of euthanasia opponents are unfounded.[3]

The slippery slope[edit]

As applied to the euthanasia debate, the slippery slope argument claims that the acceptance of certain practices, such as physician-assisted suicide or voluntary euthanasia, will invariably lead to the acceptance or practice of concepts which are currently deemed unacceptable, such as non-voluntary or involuntary euthanasia. Thus, it is argued, in order to prevent these undesirable practices from occurring, we need to resist taking the first step.[4]

There are two basic forms which the argument may take, each of which involves different arguments for and against.[4][5] The first of these, referred to as the logical version, argues that the acceptance of the initial act, A, logically entails the acceptance of B, where A is acceptable but B is an undesirable action.[5] This version is further refined into two forms based on how A entails B. In the first, it is argued that there "is no relevant conceptual difference between A and B"[6] – the premises that underlie the acceptance of A logically entail the acceptance of B. Within the euthanasia debate, van der Burg identifies one of Richard Sherlock's objections to Duff and Campbell as fitting this model.[6] Duff and Campbell had presented an argument for the selective non-treatment of newborns suffering from serious defects. In responding to Duff and Campbell's stance, Sherlock argued that the premises which they employed in order to justify their position would be just as effective, if not more-so, in justifying the non-treatment of older children: "In short, if there is any justification at all for what Duff and Campbell propose for newborns then there is better justification for a similar policy with respect to children at any age."[7]

The second logical form of the slippery slope argument, referred to as the "arbitrary line" version,[8] argues that the acceptance of A will lead to the acceptance of A1, as A1 is not significantly different from A. A1 will then lead to A2, A2 to A3, and eventually the process will lead to the unacceptable B.[6] As Glover argues, this version of the argument does not say that there is no significant difference between A and B, but instead argues that it is impossible to justify accepting A while also denying B – drawing a line at any point between the two would be creating an arbitrary cut-off point that would be unjustifiable.[9] Glover provides the example of infanticide (or non-voluntary euthanasia) and severely deformed children:

"If it is allowable at birth for children with some grave abnormality, what will we say about an equally grave abnormality that is only detectable at three months? And another that is only detectable at six months? And another that is detectable at birth only slightly less serious? And another that is slightly less serious than that one?"

— Jonathan Glover[10]

The second primary form of the slippery slope argument is that of the "Empirical" or "Psychological" argument.[4][5][8] The empirical version does not rely on a logical connection between A and B, but instead argues that an acceptance of A will, in time, lead to an acceptance of B.[4] The process is not a logical necessity, but one which will be followed through a process of moral change.[11] Enoch describes the application of this form of the argument thus:

"Once we allow voluntary euthanasia, she argues, we may (or will) fail to make the crucial distinction, and then we will make the morally unacceptable outcome of allowing involuntary euthanasia; or perhaps even though we may make the relevant distinction, we will not act accordingly for some reason (perhaps a political reason, or a reason that has to do with weakness of will, or some other reason)."

— David Enoch[12]

Glover, however, notes that this line of argument requires good evidence that this direction will be followed, as not all boundaries are thus pushed.[13]

More generally, it has been argued that in employing the slippery slope there can be an "implicit concession", as it starts from the assumption that the initial practice is acceptable – even though it will lead to unacceptable outcomes in the future.[14] Nevertheless, van der Burg argues that this not a useful concession, as the outcomes are intended to make it clear that the initial practice was not justifiable after all.[15]

Response to the logical versions[edit]

Countering the first logical version of the slippery slope argument, it is argued that the different types of euthanasia are sufficiently distinct that it is not "logically inconsistent" to support one version while denying the others. It is possible to support, for example, voluntary euthanasia while denying non-voluntary euthanasia, just as it is possible to support both – the distinction comes not from a logical inconsistency, but a choice of principles, such that a focus on euthanasia as personal choice will support voluntary euthanasia but not non-voluntary euthanasia, while a focus on a person's "best interests" may allow for the support of both.[8] From a more practical perspective, another option when faced with the logical version of the argument is to simply accept the consequences. This was the response by Duff and Campbell to Sherlock. Rather than arguing that their premises were flawed, they argued that Sherlock was correct: their criteria could also be applied to older children, and thus it should be applied, as it was "probably the most caring policy generally."[16]

In responding to the "arbitrary line" version of the slippery slope argument, it is argued that the stance relies on the "paradox of the heap", and that it is possible to draw a line between the acceptable and unacceptable alternatives.[9] Furthermore, in the case of euthanasia, it is possible to draw hard lines between different types of practices. For example, there is a clear distinction between voluntary and non-voluntary euthanasia, such that the arbitrary line approach cannot be applied.[8]

The empirical argument[edit]

Glover argues that the empirical argument needs to be backed by evidence, as there are situations where we do not seem to push boundaries.[13] Generally, two examples are discussed – Action T4, the Nazi euthanasia program in Germany between 1939 and 1941, and the Groningen Protocol in the Netherlands, which has allowed for non-voluntary euthanasia of severely deformed newborns.

Lewis notes that the focus has been on voluntary to non-voluntary euthanasia, rather than physician-assisted suicide to voluntary euthanasia, as there have been no instances of the latter: in jurisdictions where physician-assisted suicide have been legalised, there have been no moves to legalise voluntary euthanasia, while jurisdictions that have legalised voluntary euthanasia also allowed physician-assisted suicide at the same time.[17]

Action T4[edit]

Leo Alexander, in examining the events of the Holocaust during the Nuremberg Trials, stated that the origins of the Nazi programs could be traced back to "small beginnings", and presented a slippery slope argument.[18] Others have argued that Action T4 is not an example of the empirical slippery slope,[8] as euthanasia was still a criminal act in Germany during that time, and there is "no record of the Nazi doctors either killing or assisting in the suicide of a patient who was suffering intolerably from a fatal illness".[19]

Euthanasia historian Ian Dowbiggin linked the Nazis' Action T4 to the resistance in the West to involuntary euthanasia. He believes that the revulsion inspired by the Nazis led to some of the early advocates of euthanasia in all its forms in the U.S. and U.K. removing non-voluntary euthanasia from their proposed platforms.[20]

The Groningen Protocol[edit]

Non-voluntary euthanasia is sometimes cited as one of the possible outcomes of the slippery slope argument, in which it is claimed that permitting voluntary euthanasia to occur will lead to the support and legalization of non-voluntary and involuntary euthanasia.[21] Some studies of the Netherlands after the introduction of voluntary euthanasia state that there was no evidence to support this claim[22][23] while other studies state otherwise.[24]

A study from the Jakobovits Center for Medical Ethics in Israel argued that a form of non-voluntary euthanasia, the Groningen Protocol, has "potential to validate the slippery-slope argument against allowing euthanasia in selected populations".[25] Anesthesiologist William Lanier says that the "ongoing evolution of euthanasia law in the Netherlands" is evidence that a slippery slope is "playing out in real time".[26] Pediatrician Ola Didrik Saugstad says that while he approves of the withholding of treatment to cause the death of severely ill newborns where the prognosis is poor, he disagrees with the active killing of such newborns.[27] Countering this view, professor of internal medicine Margaret Battin finds that there is a lack of evidence to support slippery slope arguments.[28] Additionally, it is argued that the public nature of the Groningen Protocol decisions, and their evaluation by a prosecutor, prevent a "slippery slope" from occurring.[3][29]

A study by Jochemsen and Keown, from the Dutch Lindeboom Institute [30] published in the peer reviewed Journal of Medical Ethics, argued that euthanasia in the Netherlands is not well controlled and that there is still a significant percentage of cases of euthanasia practiced illegally.[24] Raanan Gillon, from the Imperial College School of Medicine, University of London commented that "what is shown by the empirical findings is that restrictions on euthanasia that legal controls in the Netherlands were supposed to have implemented are being extensively ignored and from that point of view it is surely justifiable to conclude, as Jochemsen and Keown do conclude, that the practice of euthanasia in the Netherlands is in poor control".[31] A similar conclusion was presented by Herbert Hendin, who argued that the situation in The Netherlands demonstrated a slippery slope in practice, changing the attitudes of doctors over time and moving them from tightly regulated voluntary euthanasia for the terminally ill to the acceptance of euthanasia for people suffering from psychological distress, and from voluntary euthanasia to the acceptance of non-voluntary and potentially involuntary euthanasia.[32]

A 2009 review study of euthanasia in the Netherlands concluded that no slippery slope effect has occurred,[33] while another study of the same year found that abuse of the Dutch euthanasia system is rare.[34] In 2010, a study found that there is no evidence that legalizing assisted suicide will lead us down the slippery slope to involuntary euthanasia.[35]

Most critics rely predominantly on Dutch evidence of cases of "termination of life without an explicit request" as evidence for the slide from voluntary euthanasia to non-voluntary euthanasia.[36] One commenter wrote that critics who rely on this slippery slope argument often omit two important elements, thereby using flawed logic.[36] First, the argument is only effective against legalization if it is legalization which causes the slippery slope; and secondly, it is only effective if it is used comparatively, to show that the slope is more slippery in the Netherlands than it is in jurisdictions which have not legalized assisted suicide or euthanasia;[36] since these questions have not been addressed by critics, little attention has been paid to available evidence on causation and comparability.

Research review studies[edit]

In the most recent review paper on euthanasia in the Netherlands, namely the 2009 paper entitled Two Decades of Research on Euthanasia from the Netherlands. What Have We Learnt and What Questions Remain? written by researchers from the Department of Public Health in the Netherlands, it was found that "public control and transparency of the practice of euthanasia is to a large extent possible" and that "[n]o slippery slope seems to have occurred".[33] The researchers find that the legalization of euthanasia in the Netherlands did not result in a slippery slope for medical end-of-life practices because:[33]

  1. The frequency of ending of life without explicit patient request did not increase over the studied years;
  2. There is no evidence for a higher frequency of euthanasia, compared with background populations, among:

In 2010, 4050 persons died from euthanasia or from assisted suicide on request. According to research done by the Vrije Universiteit (Amsterdam), University Medical Center Utrecht and Statistics Netherlands, and published in The Lancet, this is not more than before the introduction of the "Termination of Life on Request and Assisted Suicide (Review Procedures) Act" in 2002. Both in the Netherlands and in Belgium, the number of termination of life without explicit request for terminally ill patients, decreased after the introduction of the legislation about the termination of life. In effect, the legislation did not lead to more cases of euthanasia and assisted suicide on request.[37]


  1. ^Pappas 1996, p. 389
  2. ^Volok 2003, pp. 1057–1058
  3. ^ abDayton, Leigh (October 16, 2010). "Laws can safeguard the dying". The Australian. Retrieved December 24, 2010. 
  4. ^ abcdLewis 2007, p. 197
  5. ^ abcvan der Burg 1991, p. 43
  6. ^ abcvan der Burg 1991, p. 44
  7. ^Sherlock, Richard (1979). "Selective non-treatment of newborns". Journal of Medical Ethics. 5 (3): 140. doi:10.1136/jme.5.3.139. PMC 1154742. PMID 90725. 
  8. ^ abcde"Voluntary Euthanasia". Stanford Encyclopedia of Philosophy. Retrieved 4 January 2011. 
  9. ^ abGlover 1977, p. 166
  10. ^Glover 1977, p. 165
  11. ^van der Burg 1991, p. 51
  12. ^Enoch, David (2001). "Once You Start Using Slippery Slope Arguments, You're on a Very Slippery Slope". Oxford Journal of Legal Studies. 21 (4): 631. doi:10.1093/ojls/21.4.629. 
  13. ^ abGlover 1977, p. 167
  14. ^Schauer, Frederick (1985). "Slippery slopes". Harvard Law Review. 99 (2): 368–369. JSTOR 1341127. 
  15. ^van der Burg 1991, p. 42
  16. ^Campbell, A G M; Duff, R S (September 1979). "Author's response to Richard Sherlock's commentary". Journal of Medical Ethics. 5 (3): 141. doi:10.1136/jme.5.3.141. PMC 1154743. 
  17. ^Lewis 2007, pp. 197–198
  18. ^Wright, Walter (2000). "Historical Analogies, Slippery Sloped, and the Question of Euthanasia". Journal of Law, Medicine and Ethics. 28 (2): 176–186. doi:10.1111/j.1748-720x.2000.tb00008.x. 
  19. ^Pappas 1996, p. 390
  20. ^Dowbiggin, Ian Robert (2002). A merciful end: the euthanasia movement in modern America. New York: Oxford University Press. pp. [page needed]. ISBN 0-19-515443-6. 
  21. ^"Voluntary Euthanasia". Stanford Encyclopedia of Philosophy. Stanford University. March 29, 2010. Retrieved June 13, 2010. 
  22. ^Ryan, C.J. (October 1998). "Pulling up the runaway: the effect of new evidence on euthanasia's slippery slope". Journal of Medical Ethics. 24 (5): 341–344. doi:10.1136/jme.24.5.341. PMC 1377611. PMID 9800591. 
  23. ^van der Maas, P.J.; van Delden, J.J.M. (1991). "Euthanasia and other medical decisions concerning the end of life". The Lancet. 338 (8768): 669–674. doi:10.1016/0140-6736(91)91241-L. 
  24. ^ abJochemsen H, Keown J (February 1999). "Voluntary euthanasia under control? Further empirical evidence from The Netherlands". J Med Ethics. 25 (1): 16–21. doi:10.1136/jme.25.1.16. PMC 479162. PMID 10070633. 
  25. ^Jotkowitz, Alan; Glick, S; Gesundheit, B (2008). "A Case Against Justified Non-Voluntary Active Euthanasia (The Groningen Protocol)". The American Journal of Bioethics. 8 (11): 25. doi:10.1080/15265160802513085. ISSN 1526-5161. 
  26. ^Lanier, William; Berge, K. H. (September 2007). "Physician Involvement in Capital Punishment: Simplifying a Complex Calculus". Mayo Clinic Proceedings. 82 (9): 1043–1046. doi:10.4065/82.9.1043-a. 
  27. ^Saugstad, OD. (Nov 2005). "When newborn infants are bound to die". Acta Paediatr. 94 (11): 1535–7. doi:10.1080/08035250500340412. PMID 16303690. 
  28. ^Battin, Margaret P. (2008). "Physician-Assisted Dying and the Slippery Slope: The Challenge of Empirical Evidence". Willamette Law Review. 45 (1): 107–108. 
  29. ^Sauer, Pieter J.J.; Verhagen, A.A. Eduard (2009). "The Groningen Protocol, Unfortunately Misunderstood". Neonatology. 96 (1): 11–2. doi:10.1159/000196883. PMID 19176978. 
  30. ^"Lindeboom Instituut Studiecentrum voor medische ethiek vanuit de christelijke levensbeschouwing". Retrieved 2011-01-01. 
  31. ^Raanan Gillon (February 1999). "Euthanasia in the Netherlands - down the slippery slope ?". J Med Ethics. 25 (1): 3–4. doi:10.1136/jme.25.1.3. PMC 479159. PMID 10070630. 
  32. ^Hendin, Herbert. (1996-1997). "The Slippery Slope: The Dutch Example", Duquesne Law Review, 35:1. p427.
  33. ^ abcdRietjens JA, van der Maas PJ, Onwuteaka-Philipsen BD, van Delden JJ, van der Heide A (September 2009). "Two Decades of Research on Euthanasia from the Netherlands. What Have We Learnt and What Questions Remain?". J Bioeth Inq. 6 (3): 271–283. doi:10.1007/s11673-009-9172-3. PMC 2733179. PMID 19718271. 
  34. ^Norwood, F.; Kimsma, G.; Battin, MP. (Dec 2009). "Vulnerability and the 'slippery slope' at the end-of-life: a qualitative study of euthanasia, general practice and home death in The Netherlands". Fam Pract. 26 (6): 472–80. doi:10.1093/fampra/cmp065. PMID 19828573. 
  35. ^Lesser, H. (Apr 2010). "Should it be legal to assist suicide?". J Eval Clin Pract. 16 (2): 330–4. doi:10.1111/j.1365-2753.2010.01394.x. PMID 20367858. 
  36. ^ abcLewis 2007
  37. ^(in Dutch)Euthanasiewet leidde niet tot meer euthanasie

Further reading[edit]

The Fifth Commandment: The Slippery Slope of Euthanasia

Bob Kurland • March 16, AD2015

“On the morning of February 6, 2015, the Supreme Court of Canada ruled that the law against assisted suicide was unconstitutional. Canada now joins a small, elite group of madly progressive countries in abandoning the most fundamental principle in all of nature.” Joe Bissonette, “Physician-assisted suicide and spiritual suicide” (Crisis Magazine)

He hath set fire and water before thee: stretch forth thy hand unto whether thou wilt. Before man is life and death, and whether him liketh shall be given him.”Sirach 15:16,17 (KJV)

 “Sometime in the 23rd century…the survivors of war, 

overpopulation and pollution are living in a great domedcity, sealed away from the forgotten world outside. 

Here in an ecologically balanced world, mankind lives only

for pleasure, freed by the servo-mechanisms which provide 

everything. There’s just one catch. Life must end at thirty 

unless reborn in the fiery ritual of carousel.  “Introduction to Logan’s Run (the movie)

Those of you of a certain age (55+) might remember the movie Logan’s Run,  about a dystopic society that maintains equilibrium between population and resources by the simple expedient of killing anyone who reaches the age of 30. I was reminded of this after reading a fine post, The Obligation to Die,  by Ben Butera, of the blog “Two Catholic Men and a Blog”.  I will use much of his post, but I urge the reader to go to the original. And then I will show that Ben’s projection is realistic by looking at some statistics for euthanasia in the Netherlands, where it has reached an advanced stage.


In his post Ben lists the following four stages for instituting governmental sponsorship and control of euthanasia:

“STAGE 1: Voluntary – Passive (Completely voluntary, but not applauded)…doctors may now lawfully help competent adults to kill themselves if they are terminally ill. Certainly, no one would be forced to do it, because that would be unthinkable. There should be no coercion either, since it’s such a personal choice between patients and their doctor.

“STAGE 2: Voluntary – Active
(Completely voluntary and encouraged)
…We need to think of what is best, not only for ourselves, but for our immediate families and the common good of society. … we have an obligation to encourage what is “right” and promote the common welfare. The “right to die” can now slowly morph into the ‘obligation to die’….Persistent pressure to do the “right thing” will break the will to live.

“STAGE 3: Mandatory – Passive
(Mostly voluntary with SOME EXCEPTIONS [
emphasis added]) …As our population rapidly ages and the health care costs consume ever larger proportions of government budgets, at least some legislation must be considered to help reduce the source of rising healthcare cost. Laws to guide the old and terminally ill through their final stage of life and their final obligation to the society just makes sense.

“STAGE 4: Mandatory – Active
(Mostly required with some exceptions)  
Physician assisted suicide need not be limited to only desperate pain. The very old, very sick and severely physically or mentally handicapped should all be considered for legal and mandatory euthanization once the quality of life has been properly assessed by professionals…Why allow these poor people to suffer for no reason, even if they choose to suffer?  …Those in favor of such legislation will be called progressively “pro-health”. Those opposed will be said to have radical “anti-health” agenda.”

Frightening, isn’t it, especially for those of us over the Biblical allotted span of fourscore and ten? Ben shows how morphing from rare and voluntary to usual and mandatory would take place. As in abortion, Orwellian doublethink will be used to mask the moral shame: just as “for killing the unborn” read “pro-choice”, so “for compulsory killing of the ‘unfit'” read “pro-health”.


We have a crystal ball to see how Ben’s forecast might work out in reality: the story of euthanasia in the Netherlands and Belgium. (I should note that three states–Oregon, Vermont and Washington–have laws that physician-assisted suicide is legal, corresponding to Stage 1, above.)

A physician-assisted suicide was approved by a Netherlands judge in 1984 and legislation enacted in 2001 and 2002 that would approve physician-assisted suicide generally in the Netherlands. Would these Dutch legislators have foreseen that in 2013 a 47 year old woman (with two adolescent sons) would request and receive physician-assisted suicide because she could not live with tinnitus (ringing in the ears)?  (The clinic was reprimanded for being “careless” in not exploring other medical solutions!)

Statistics about euthanasia in The Netherlands and Belgium are truly frightening to those of us who hold that life is sacred and in God’s hands. To spare the reader, I’ll not go into the numbers in detail, but summarize conclusions and give links to original articles.


The position of the Church on euthanasia is clearly spelled out in the Catholic Catechism:

  • “2277 Whatever its motives and means, direct euthanasia consists in putting an end to the lives of handicapped, sick, or dying persons. It is morally unacceptable [emphasis added]. Thus an act or omission which, of itself or by intention, causes death in order to eliminate suffering constitutes a murder gravely contrary to the dignity of the human person and to the respect due to the living God, his Creator. The error of judgment into which one can fall in good faith does not change the nature of this murderous act, which must always be forbidden and excluded.
  • 2278 Discontinuing medical procedures that are burdensome, dangerous, extraordinary, or disproportionate to the expected outcome can be legitimate [emphasis added]. It is the refusal of “over-zealous” treatment. Here one does not will to cause death; one’s inability to impede it is merely accepted. The decisions should be made by the patient if he is competent and able or, if not, by those legally entitled to act for the patient, whose reasonable will and legitimate interests must always be respected.
  • 2279 Even if death is thought imminent, the ordinary care owed to a sick person cannot be legitimately interrupted. The use of painkillers to alleviate the sufferings of the dying, even at the risk of shortening their days, can be morally in conformity with human dignity if death is not willed as either an end or a means, but only foreseen and tolerated as inevitable [emphasis added].”

Not much more need be said, but to emphasize that, out of respect for life, we should not put an end the lives of the handicapped (whatever their age), the sick (physically or mentally), or the dying.

In this article we have not, near the anniversary of Terry Schiavo’s death, specifically considered the right to life of comatose or consciousness-impaired patients. However, the framework of what we, as Catholics, should do is set forth in articles 2278 and 2279 above.


I don’t have an answer to that question. How about you, readers?


John I. Fleming, Euthanasia, The Netherlands and Slippery Slopes.

Nicanor Austriaco, Biomedicine and Beatitude, Bioethics at the End of Life.

NOTE   Ben has another fine post on this subject, The Obligation to Live and Give,  which has a sunnier view on this topic than I have presented here.   Let’s hope he’s right!

Photography: See our Photographers page.

Filed in: Faith & Spirituality, Marriage & Family, Sanctity of Life • Tags: euthanasia, euthanasia and the Catholic Church, Euthanasia in Belgium, euthanasia in The Netherlands, physician-assisted suicide

About the Author: Bob Kurland

Retired, cranky, old physicist. Convert to Catholicism in 1995. Trying to show that there is no contradiction between what science tells us about the world and our Catholic faith. Intermittent blogs at Rational Catholic and adult education classes here to achieve this end. Extraordinary Minister of Communion volunteer to federal prison and hospital; lector, EOMC. Sometime player of bass clarinet, alto clarinet, clarinet, bass, tenor bowed psaltery for parish instrumental group and local folk group. And, finally, my motivation: “It is also necessary—may God grant it!—that in providing others with books to read I myself should make progress, and that in trying to answer their questions I myself should find what I am seeking. Therefore at the command of God our Lord and with his help, I have undertaken not so much to discourse with authority on matters known to me as to know them better by discoursing devoutly of them.” St. Augustine of Hippo, The Trinity I,8.


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