- Email: [email protected]
Reply: the lure of inductivism
Correspondence
anaesthesia’ as if it was a self-evident notion, which it is not. In fact, the reference supporting this claim is a recently published, highly interesting but purely hypothetical and speculative paper by Sanders and colleagues,3 which proposes the construct of ‘connected consciousness’ instead of ‘wakefulness’ to describe IFT responsiveness. Crucially, the only empirical evidence for the existence of a state of ‘connected consciousness’ under anaesthesia is the IFT phenomenon itself. In other words, the neurobiological significance of the phenomenon is derived from a hypothesis that was generated to explain the phenomenon. Circular reasoning? Second, from this ‘circular reasoning’ embedded within the authors’ proprietary hypothetical model (multilevel block by anaesthetics in limbic system, basal ganglia, and spinal cord), clinical practice-related claims are deduced. The existence of a ‘protective’ (against what?) effect of amnesia is first postulated but immediately called into question based on the potential of (harmful?) ‘long-term consequences’ that a state of ‘IFT responsiveness’ may cause. Considering the high prevalence of IFT responsiveness and the lack of prima facie evidence of any harm in the patient population at large, one wonders why the postulated ‘protective’ effect of amnesia should be called into question. The authors address this lack of evidence by demanding that studies be conducted to uncover a problem (‘long-term consequences’ of the postulated subconscious but nevertheless detrimental ‘experience of surgery’) that neither patients nor clinicians are aware of. Are we crying wolf (again)? Finally, based on a hypothetical harm resulting from a hypothetical condition, the authors not only impose a ‘moral imperative’ to ablate the experience of surgery that goes beyond
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standard practice but also propose the use of speculative pharmacological interventions ‘for the sake of patient comfort’, in the absence of any evidence of discomfort. Maybe, the search for and study of conjectural harm caused by a phenomenon of unknown behavioural significance is a sign of maturity. In comparison to the real horrors of surgery without anaesthesia (http:// wesclark.com/jw/mastectomy.html), we have truly come a long way. Where the wisdom of building a case for scholarly investigation of an intellectually intriguing, experimentally accessible, and possibly scientifically interpretable phenomenon on the threat of ‘long-term health consequences’ is concerned, I remain sceptical. It has the potential to cause a lot of unwarranted anxiety among both patients and anaesthetists. Let us avoid the temptation of replacing evidence with inductive reasoning.
Declaration of interest None declared.
References 1. Sanders RD, Absalom A, Sleigh JW. V. ‘For now we see through a glass, darkly’: the anaesthesia syndrome. Br J Anaesth 2014; 112: 790–3 2. Zand F, Hadavi SM, Chohedri A, Sabetian P. Survey on the adequacy of depth of anaesthesia with bispectral index and isolated forearm technique in elective Caesarean section under general anaesthesia with sevoflurane. Br J Anaesth 2014; 112: 871–8 3. Sanders RD, Tononi G, Laureys S, Sleigh J. Unresponsiveness ≠ unconsciousness. Anesthesiology 2012; 116: 946–59 doi:10.1093/bja/aev081
Reply from the authors
Reply: the lure of inductivism J. Sleigh1, *, R. Sanders2, and A. Absolom3 1
Hamilton, New Zealand, 2London, UK, and 3Groningen, The Netherlands
*E-mail: [email protected]
Editor—We thank Dr Perouansky for his interest in our editorial1 and wholeheartedly agree as to the dangers of inductive logic; this is the well-known philosophical problem of the ‘inductive fallacy’. We would, however, point out that the whole of (nonmathematical) science is built on the shaky foundation that observations of facts can be generalized. ‘If the sun rose today and yesterday etc, then it will rise tomorrow . . . ’ Zand and colleagues2 observed some surprising facts; that is, patients who looked as if they were suitably anaesthetized were able to respond to verbal commands. These facts appear unusual and therefore demand some sort of explanation. The editorial was an attempt to provide a framework for such an explanation. We do not expect that the explanation we offered is the best one and are very happy for others to provide better; however, we do not accept that ignoring the facts is a reasonable option. Are these observations important clinically? We will not know until more work is done. Are these observations important
scientifically as regards understanding the state of general anaesthesia and consciousness? Probably, yes.
Declaration of interest None declared.
References 1. Sanders RD, Absalom A, Sleigh JW on behalf of the ConsCIOUS Group. V. ‘For now we see through a glass, darkly’: the anaesthesia syndrome. Br J Anaesth 2014; 112: 790–3 2. Zand F, Hadavi SM, Chohedri A, Sabetian P. Survey on the adequacy of depth of anaesthesia with bispectral index and isolated forearm technique in elective Caesarean section under general anaesthesia with sevoflurane. Br J Anaesth 2014; 112: 871–8 doi:10.1093/bja/aev082
anaesthesia’ as if it was a self-evident notion, which it is not. In fact, the reference supporting this claim is a recently published, highly interesting but purely hypothetical and speculative paper by Sanders and colleagues,3 which proposes the construct of ‘connected consciousness’ instead of ‘wakefulness’ to describe IFT responsiveness. Crucially, the only empirical evidence for the existence of a state of ‘connected consciousness’ under anaesthesia is the IFT phenomenon itself. In other words, the neurobiological significance of the phenomenon is derived from a hypothesis that was generated to explain the phenomenon. Circular reasoning? Second, from this ‘circular reasoning’ embedded within the authors’ proprietary hypothetical model (multilevel block by anaesthetics in limbic system, basal ganglia, and spinal cord), clinical practice-related claims are deduced. The existence of a ‘protective’ (against what?) effect of amnesia is first postulated but immediately called into question based on the potential of (harmful?) ‘long-term consequences’ that a state of ‘IFT responsiveness’ may cause. Considering the high prevalence of IFT responsiveness and the lack of prima facie evidence of any harm in the patient population at large, one wonders why the postulated ‘protective’ effect of amnesia should be called into question. The authors address this lack of evidence by demanding that studies be conducted to uncover a problem (‘long-term consequences’ of the postulated subconscious but nevertheless detrimental ‘experience of surgery’) that neither patients nor clinicians are aware of. Are we crying wolf (again)? Finally, based on a hypothetical harm resulting from a hypothetical condition, the authors not only impose a ‘moral imperative’ to ablate the experience of surgery that goes beyond
| 849
standard practice but also propose the use of speculative pharmacological interventions ‘for the sake of patient comfort’, in the absence of any evidence of discomfort. Maybe, the search for and study of conjectural harm caused by a phenomenon of unknown behavioural significance is a sign of maturity. In comparison to the real horrors of surgery without anaesthesia (http:// wesclark.com/jw/mastectomy.html), we have truly come a long way. Where the wisdom of building a case for scholarly investigation of an intellectually intriguing, experimentally accessible, and possibly scientifically interpretable phenomenon on the threat of ‘long-term health consequences’ is concerned, I remain sceptical. It has the potential to cause a lot of unwarranted anxiety among both patients and anaesthetists. Let us avoid the temptation of replacing evidence with inductive reasoning.
Declaration of interest None declared.
References 1. Sanders RD, Absalom A, Sleigh JW. V. ‘For now we see through a glass, darkly’: the anaesthesia syndrome. Br J Anaesth 2014; 112: 790–3 2. Zand F, Hadavi SM, Chohedri A, Sabetian P. Survey on the adequacy of depth of anaesthesia with bispectral index and isolated forearm technique in elective Caesarean section under general anaesthesia with sevoflurane. Br J Anaesth 2014; 112: 871–8 3. Sanders RD, Tononi G, Laureys S, Sleigh J. Unresponsiveness ≠ unconsciousness. Anesthesiology 2012; 116: 946–59 doi:10.1093/bja/aev081
Reply from the authors
Reply: the lure of inductivism J. Sleigh1, *, R. Sanders2, and A. Absolom3 1
Hamilton, New Zealand, 2London, UK, and 3Groningen, The Netherlands
*E-mail: [email protected]
Editor—We thank Dr Perouansky for his interest in our editorial1 and wholeheartedly agree as to the dangers of inductive logic; this is the well-known philosophical problem of the ‘inductive fallacy’. We would, however, point out that the whole of (nonmathematical) science is built on the shaky foundation that observations of facts can be generalized. ‘If the sun rose today and yesterday etc, then it will rise tomorrow . . . ’ Zand and colleagues2 observed some surprising facts; that is, patients who looked as if they were suitably anaesthetized were able to respond to verbal commands. These facts appear unusual and therefore demand some sort of explanation. The editorial was an attempt to provide a framework for such an explanation. We do not expect that the explanation we offered is the best one and are very happy for others to provide better; however, we do not accept that ignoring the facts is a reasonable option. Are these observations important clinically? We will not know until more work is done. Are these observations important
scientifically as regards understanding the state of general anaesthesia and consciousness? Probably, yes.
Declaration of interest None declared.
References 1. Sanders RD, Absalom A, Sleigh JW on behalf of the ConsCIOUS Group. V. ‘For now we see through a glass, darkly’: the anaesthesia syndrome. Br J Anaesth 2014; 112: 790–3 2. Zand F, Hadavi SM, Chohedri A, Sabetian P. Survey on the adequacy of depth of anaesthesia with bispectral index and isolated forearm technique in elective Caesarean section under general anaesthesia with sevoflurane. Br J Anaesth 2014; 112: 871–8 doi:10.1093/bja/aev082