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A patient believes she will recover against the odds. Is that irrational?

Tsion Bekele Fellow
· 4 replies
Rationality & probabilityAnalyticIslamicModern European#evidentialism#instrumental-rationality#medicine#optimism
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Its coordinates: 2.6 Rationality · 2.8 Formal Epistemology

A situation I meet in different forms every month, described here as a composite. A woman with a serious illness has, by the best evidence we have, about a one in three chance of recovering. She tells her doctor, and me, calmly and repeatedly, that she will recover. Not that she hopes to. That she will.

Is this irrational?

By one standard, obviously yes. Rational belief should be proportioned to the evidence, and the evidence says one in three. Believing it is certain is a mistake, the way believing a coin will land heads is a mistake.

By another standard, possibly not. If the belief helps her eat, sleep, keep appointments and endure treatment, then holding it may improve her odds a little. The research on whether optimism itself changes outcomes is, I think, weaker and more mixed than popular books suggest. But suppose it helps somewhat. Then the belief serves her ends, and believing what serves your ends is also a kind of rationality.

These two standards give opposite verdicts, and I don't think one is a trick. "Rational" seems to be doing two jobs: tracking truth and serving goals. Usually they coincide. At the bedside they sometimes don't.

My practical question: her doctor's duty is to tell her the truth about her prognosis. Is it also a duty to correct her belief? Or is her belief something other than a probability estimate, so that there is nothing to correct?

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4 replies

  1. Omar Ragab

    Fellow

    In Cairo I see this often in our patients, and very often the confidence is religious. There is a well-known hadith in which God says, "I am as My servant thinks of Me." Many patients take this as a reason to think well of God, husn al-ẓann, and to expect good.

    I have come to think that this is not a credence about survival at all. It is an attitude of trust towards the outcome, whatever it is. When I have asked such patients what they will do if the treatment fails, they are not shaken. They say God knows best. That is not a one-in-three estimate that has been rounded up. It is a different kind of state, and I would not "correct" it.

    Helpful · 2
  2. Rowena Abellana

    Fellow

    Gabriel Marcel draws a distinction here that I teach every year. Optimism, for him, is a spectator's confidence that things will turn out well. Hope is something else: a commitment from inside a trial, a refusal to let the situation close in on itself. Hope doesn't need high odds and doesn't claim them.

    Your patient's words sound like optimism ("I will recover"), but what she may be doing is hoping. If so, there is no irrational belief to fix. There is a way of standing in her illness.

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  3. Wanjiru Njenga

    Fellow

    A Bayesian angle. Some philosophers distinguish belief from acceptance. Belief is your credence, how confident you actually are. Acceptance is treating something as true for the purposes of acting: planning, committing, behaving as if. You can accept that you will recover, and organise your life around it, while your credence remains one in three.

    If that's what she is doing, she is not irrational in either sense. She has an accurate credence and a useful policy. The trouble only comes if the acceptance swallows the credence, for instance if she refuses an option because she is "certain" she won't need it.

  4. Tsion Bekele

    Fellow

    Thank you. All three of you, in different words, say the same thing: what looks like a false belief may be a different attitude, trust, hope or acceptance, that does not compete with the evidence.

    Wanjiru's last point gives me a working rule. Nobody needs to correct her confidence. Someone does need to check that it isn't making decisions for her, such as refusing palliative planning because she "won't need it". That is where truth-telling has to come in, gently.

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