NEUROETHICS / PSYCHEDELICS I

Psychedelics

Treatment, insight, and illusion

A PATIENT’S REPORT

A loving cosmic plan.

Less fear of death.
A more enjoyable life.

Does the relief depend
on a comforting illusion?

Trevor asks: Would truth still matter if you were dying and afraid?

THE PHILOSOPHICAL PUZZLE

Insight and illusion

INSIGHT

A new understanding
of oneself and reality.

ILLUSION

A powerful certainty
that may be mistaken.

Can a treatment improve a life
by worsening its understanding of reality?

Mackenzie asks: Does the value lie in revealing truth or changing how we see life?

THE INTERVENTION

Psychedelic therapy

Classic psychedelics: psilocybin, LSD, mescaline, DMT.

Characteristic effects depend importantly on 5-HT2A receptor activation.

Preparation

Screening, expectations,
and trust.

Session

Drug administration
and support.

Integration

Interpreting the experience
and returning to life.

The intervention includes a person, an experience, and a context.

William asks: Why do people respond to psychedelics differently?

THE CANCER-DISTRESS TRIAL

Symptoms after supported psilocybin sessions

51 analyzed participants with cancer-related distressHigh vs. very low dose; support in both conditions

RANDOM ASSIGNMENTSESSION 15 WEEKS LATERSESSION 2

High dose first

High dose

→

Very low dose

Low dose first

Very low dose

→

High dose

Each participant receives both conditions.
The first comparison occurs before the groups switch doses.

First comparison: 5 weeks after session 1.
Sessions were 5 weeks apart.

After crossover, both groups
have received the high dose.

Evidence of durable relief. The mechanism remains to be explained.

William asks: How can a change in perspective persist after the drug wears off?

WHAT THE PATIENT REPORTS

Experience, interpretation, and belief

EXPERIENCEINTERPRETATIONLASTING BELIEF

Boundaries between
self and world dissolved.

Contact with a
larger consciousness.

A change in how
the self is experienced.

Consciousness can exist
independently of the body.

My usual sense of self
can change.

Noetic quality: the feeling of knowing or revelation.

Felt certainty leaves a question about justification.

Mackenzie asks: Can an experience give genuine knowledge if its apparent revelation is unproven?

THE DISPUTED CAUSAL INFERENCE

What explains the improvement?

RANDOMLY ASSIGNED

Dose

MEASURED AFTER SESSION

Mystical-type
experience score

MEASURED LATER

Symptom
improvement

Other features of the session?

Does benefit require a false metaphysical belief?
The association alone does not establish that claim.

Mackenzie asks: Does an experience’s value lie in revealing truth or changing our outlook?

THE ARGUMENT

The comforting-delusion objection

1Naturalism is true.
2If naturalism is true, psychedelic therapy has a poor overall epistemic profile.
3A poor epistemic profile gives us reason to hesitate to recommend a therapy.

CWe have reason to hesitate to recommend psychedelic therapy.

Trevor asks: Does truth still matter when someone is dying and afraid?

WAYS OF RESOLVING THE PUZZLE

Four responses

ResponseHow it resolves the tensionMove in the argument

Metaphysical disclosure

Richards / Huxley

The revelation is genuine.

Reject naturalism.

Benefit despite falsity

Flanagan

Relief can outweigh epistemic costs.

Qualify the reason for caution.

Epistemic caution

Lavazza

The epistemic costs warrant hesitation.

Accept the objection.

Naturalistic epistemic benefit

Letheby

Benefit need not depend on false metaphysics.

Challenge the poor-profile premise.

Trevor asks: Would you choose Nozick’s experience machine if you were dying and afraid?

LETHEBY’S ALTERNATIVE

A different understanding of oneself

SELF-UNDERSTANDING

Nothing
can change.

Could things
be different?

I can accept help.

My fear can change.

I can act differently.

Letheby’s proposal: loosening an entrenched self-model
can make new perspectives available.

Mackenzie asks: Does it matter whether a meaningful experience has a natural or supernatural source?

SYNAPTIC PLASTICITY

A brief event can leave a lasting change

Original Figure 8.7C. Purple stimulated-pathway EPSPs rise after high-frequency stimulation and stay above baseline over the hour. Orange comparison-pathway responses remain close to baseline. — Hippocampal synaptic transmission: response to the same test stimulus.

READING THE EXPERIMENT

A brief train
of stimulation.

A stronger response
after it has ended.

Plasticity makes change possible.
It does not tell us which change is beneficial.

Hailey asks: How do negative experiences shape the reactions we later have?

GENUINE AND PLACEBO INSIGHTS

A helpful explanation can still be mistaken

“Boys should not cry” → an explanation of adult emotional habits.

What happened?

Is the childhood memory accurate?

What explains what?

Did it cause the adult difficulty?

Experience→Candidate insight→Critical evaluation

Discovery puts an idea within reach. Justification requires evidence.

Hailey asks: Can reactions we call personality come from patterns learned without noticing?

COSTS, BENEFITS, AND AVAILABLE ALTERNATIVES

Epistemic innocence

Can an imperfect cognition still provide an epistemic benefit?

1

Epistemic benefit

The cognition improves understanding or makes inquiry possible.

2

No available alternative with fewer costs

At that time, an alternative route to the same epistemic benefit is unavailable.

Both conditions need an argument. Relief alone is insufficient.

Mackenzie asks: Can an experience give knowledge when its apparent revelation is uncertain?

PATIENT VALUES AND EPISTEMIC RISK

Who decides what matters?

Patient

Weighs relief, meaning, and truth in the context of their own life.

Clinician

Explains evidence and uncertainty; assesses reasonable treatment options.

Informed choice

The experience may feel certain. Its interpretation remains open to evaluation.

Consent leaves room to question what seemed revealed.

Trevor asks: Who weighs the risk of false belief, and what should patients be told?

RETURN TO THE PATIENT

The same relief, different explanations

Metaphysical reassurance

Consciousness survives
bodily death.

Revised self-understanding

My fear and my possibilities
look different.

Suppose the relief is equally durable.
Should we evaluate these changes differently?
What would distinguish their explanations?

Next: how changing the sense of self can change a life.

William asks: How does a new view of reality carry into sober life?

READING AND ATTRIBUTION

Assigned readings

Chris Letheby

Philosophy of Psychedelics

Oxford University Press, 2021. Assigned: ch. 2, pp. 8–38; ch. 3, pp. 39–53; ch. 8, pp. 160–172 and 194–195. Optional bridge: ch. 6, pp. 110–123.

Dale Purves and colleagues

Neuroscience, sixth edition

Sinauer / Oxford University Press, 2018. Chapter 8, pp. 176–188. Figure 8.7C, p. 177, after Malinow et al. (1989). Original panel reproduced from the assigned course excerpt.

Mackenzie asks: Can an experience give genuine knowledge if its apparent revelation is unproven?

STUDIES AND FIGURES

Empirical sources

Roland R. Griffiths and colleagues

Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer

Journal of Psychopharmacology 30 (2016), 1181–1197. DOI 10.1177/0269881116675513. Chart data: Table 4. Methods, limitations, and Figure 5 support the discussion of the study.

Stephen Ross and colleagues

Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer

Journal of Psychopharmacology 30 (2016), 1165–1180. DOI 10.1177/0269881116675512. A related trial of psilocybin for cancer-related anxiety and depression.

Calvin Ly and colleagues

Psychedelics Promote Structural and Functional Neural Plasticity

Cell Reports 23 (2018), 3170–3182. DOI 10.1016/j.celrep.2018.05.022. Supplemental empirical background, not an additional assigned reading.

William asks: How can a changed perspective last after someone is sober again?