Consent and the Myth of Full Information

On the natural boundaries of informed consent.

26/07/2026 · 4 min read

In­formed con­sent is one of the fun­da­men­tal prin­ci­ples of mod­ern ethics. In med­i­cine, psy­chother­a­py, and BDSM, we as­sume that a per­son re­ceives clear and un­der­stand­able in­for­ma­tion about the na­ture of the sit­u­a­tion, its risks, and its pos­si­ble con­se­quences, and that they then freely de­cide whether to en­ter it. Well-man­aged con­sent does more than de­fine what may and may not hap­pen. It also cre­ates con­di­tions in which a per­son can safe­ly ex­plore and un­der­stand them­selves.

This prin­ci­ple is in­dis­pens­able. What is mis­lead­ing, how­ev­er, is the idea that gen­uine­ly in­formed con­sent re­quires com­plete knowl­edge of a fu­ture ex­pe­ri­ence. To pre­dict its ac­tu­al im­pact, a per­son would need to know in ad­vance not only the ex­ter­nal cir­cum­stances, but also their fu­ture bod­i­ly, emo­tion­al, and psy­cho­log­i­cal re­spons­es. This is where the para­dox of the first ex­pe­ri­ence aris­es.

Imag­ine some­one de­cid­ing to try shibari for the first time. The rig­ger can ex­plain the planned course of the ses­sion, the method of ty­ing, the phys­i­cal risks, safe­ty pro­ce­dures, com­mu­ni­ca­tion sig­nals, and ways of stop­ping. They can de­scribe the pres­sure of the rope, the re­stric­tion of move­ment, or the pos­si­ble emo­tion­al in­ten­si­ty. They can­not, how­ev­er, re­li­ably pre­dict what the ex­pe­ri­ence will mean for that par­tic­u­lar mod­el. Nor does the per­son be­ing tied know this in ad­vance.

They may be sur­prised by the loss of vi­su­al con­trol, an au­thor­i­ta­tive tone of voice, or the feel­ing of help­less­ness in a par­tic­u­lar po­si­tion. Re­strict­ed move­ment may bring up an un­ex­pect­ed mem­o­ry or as­so­ci­a­tion. Equal­ly, the per­son may dis­cov­er a pro­found sense of calm and safe­ty where they ex­pect­ed fear. Such re­ac­tions are not mere­ly ad­di­tion­al in­for­ma­tion about the prac­tice that a more ex­pe­ri­enced per­son could have shared be­fore­hand. They con­sti­tute new knowl­edge about that par­tic­u­lar per­son and arise only through the ex­pe­ri­ence it­self.

A sig­nif­i­cant part of the in­for­ma­tion that is ab­sent be­fore a first ex­pe­ri­ence is there­fore not nec­es­sar­i­ly miss­ing be­cause of poor com­mu­ni­ca­tion or con­ceal­ment. Some in­for­ma­tion does not yet ex­ist. It emerges only through the in­ter­ac­tion be­tween the sit­u­a­tion and the per­son, their body, their past, their ex­pec­ta­tions, and their cur­rent psy­cho­log­i­cal state.

This does not mean that in­formed con­sent is an il­lu­sion. It means that it has nat­ur­al lim­its. Con­sent can be valid and suf­fi­cient­ly in­formed with­out be­ing based on com­plete knowl­edge of the fu­ture ex­pe­ri­ence. What mat­ters is not om­ni­science, but the qual­i­ty of the con­di­tions un­der which the per­son makes their de­ci­sion. They need to know what is ex­pect­ed to hap­pen, what the sig­nif­i­cant risks are, what they may refuse, and how they can stop the process. At the same time, they need to know that their con­sent does not oblige them to com­plete the sit­u­a­tion.

Such a de­ci­sion also in­volves ac­cept­ing a cer­tain de­gree of un­cer­tain­ty. A per­son en­ters a sit­u­a­tion in which they may dis­cov­er a pre­vi­ous­ly un­known sen­si­tiv­i­ty, need, or bound­ary. This does not mean, how­ev­er, that they ac­cept every pos­si­ble re­ac­tion or every psy­cho­log­i­cal con­se­quence in ad­vance.

This is pre­cise­ly why some bound­aries be­come ap­par­ent only dur­ing the ex­pe­ri­ence, or even af­ter it has end­ed. Dur­ing a ses­sion, a per­son may not im­me­di­ate­ly recog­nise what is hap­pen­ing with­in them, or they may be un­able to de­scribe their state ac­cu­rate­ly. Only lat­er may they un­der­stand that a par­tic­u­lar el­e­ment was too in­tense, that at a cer­tain mo­ment they no longer felt safe, or that their ap­par­ent co­op­er­a­tion was not en­tire­ly the re­sult of a free de­ci­sion.

Such lat­er un­der­stand­ing does not, in it­self, prove that the orig­i­nal con­sent was in­valid. It of­ten means that the per­son has ac­quired new in­for­ma­tion about them­selves that they could not have pos­sessed when mak­ing the orig­i­nal de­ci­sion. A new­ly dis­cov­ered bound­ary there­fore does not au­to­mat­i­cal­ly in­val­i­date pre­vi­ous con­sent. It does, how­ev­er, change the in­for­ma­tion on which fu­ture de­ci­sions will be based.

It is there­fore more ac­cu­rate to un­der­stand in­formed con­sent not as a state achieved once and for all, but as a process through which self-knowl­edge grad­u­al­ly be­comes more pre­cise. Each ex­pe­ri­ence ex­pands the map of what a per­son knows about their body, emo­tions, needs, and bound­aries. Fu­ture con­sent can then be more pre­cise be­cause it is based not only on a gen­er­al de­scrip­tion of the prac­tice, but also on one’s own con­crete ex­pe­ri­ence.

The first con­sent there­fore can­not be as in­formed as the tenth with­out au­to­mat­i­cal­ly be­ing less valid. Its pur­pose is not to con­sti­tute an om­ni­scient de­ci­sion, but an hon­est de­ci­sion based on what can rea­son­ably be known at that mo­ment.