Mind & MortalityExplainer
What Is Consciousness?
Science can map which brain activity goes with experience. Why any of it feels like something from the inside remains one of the great open questions.
THE QUESTION LIBRARY MIND & MORTALITY
Do animals have feelings like we do?
Responsiveness, learning and felt experience are different claims, with different evidence.
THE SHORT ANSWER
There is strong scientific support for conscious experience in other mammals and birds, and a realistic possibility in many other animals, including octopuses. That does not establish that their feelings are exactly like ours. Researchers infer experience from several kinds of evidence. Plants respond and signal, but those capacities alone do not establish felt experience. Plant consciousness remains unestablished, and specific claims about plant learning need reliable replication.
- Responding to a stimulus is different from having a subjective experience.
- Evidence can support animal experience without telling us exactly what it feels like.
- Octopus experiments combine behavior, controls and nervous-system measurements.
- Plant signaling is real; it does not by itself establish consciousness.
About this picture
A common octopus. This photograph illustrates the animal; it is not from the cited experiment and cannot show what an experience feels like.
WHERE THE EVIDENCE STANDS
How sure are we?
- Other mammals and birds have conscious experience.The 2024 declaration states strong scientific support; researchers still debate methods and the character of different experiences.
- Plants transmit signals that coordinate defense responses.Toyota and colleagues directly measured a glutamate-dependent, long-distance calcium-signaling process.
- Plant responsiveness by itself establishes felt experience.A measured response supplies no automatic connection to subjective experience.
- The reported pea-plant association experiment is a reliably established learning effect.A failed replication and published methodological dispute leave that specific result contested.
- What it feels like to be an octopus remains an open question.Evidence for experience does not settle its detailed subjective character.
WHAT WE DON’T KNOW YET
We do not know the full range of feelings across animal species. Scientists also disagree about how best to test for them. Plant signals do not settle whether plants could feel anything.
WHAT WOULD CHANGE THIS ANSWER
Better tests could help tell different explanations apart. A stronger account of how feelings arise could also change our view. Repeating a learning effect would strengthen that claim. It would still leave the question of felt experience to assess.
Many animals probably feel things that are good or bad for them. That does not mean their feelings are copies of ours. An octopus could have a point of view without thinking in words. It need not see the world as a person does. The question is whether anything feels like something to the creature itself.
In 2024, a group of researchers issued the New York Declaration on Animal Consciousness. They said there is strong support for felt experience in other mammals and birds. They also see a realistic possibility in all animals with backbones and many without them, including octopuses and insects. This is their judgment of the evidence. It is not one test that settles the question for every species.
Scientists must infer feelings from what they can observe. In a 2021 octopus study, animals avoided a place linked with a harmful stimulus. They also preferred a place linked with relief. Together, these results tell us more than a simple flinch would. They support the idea of an unpleasant feeling. They do not tell us all its details.
Plants are a different case. They respond to their surroundings and send signals through their bodies. Those skills are real. But the word aware can mean two things: responding to information, or having a felt experience. A signal inside a plant does not by itself establish the second.
Keep three questions separate when you read a striking claim. What can this living thing detect? What can it learn? What suggests that it feels anything? A result can answer one question without answering all three. Each claim needs its own evidence.
THE LONG ANSWER
THE LONG ANSWER · ABOUT 5 MINUTES
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Why Does My Voice Sound Different on a Recording?
When you speak, you hear sound traveling through the air and vibrations traveling through the bones and tissues of your head.
New here?
God Plays Dice answers big questions in plain words, with sources and one of six honest labels.
Words worth knowing (4)
- Subjective experience
- Something having a felt quality for the creature itself.
- Sentience
- Often used for the capacity to have experiences such as pleasure or pain; usage varies.
- Associative learning
- Learning a relationship between events or cues, assessed through a change in response.
- Replication
- An independent attempt to obtain a reported experimental effect again.
Sources & further reading
(8) · Checked Oct 2, 2026
- The New York Declaration on Animal Consciousness ↗Declaration signatories (2024)Researcher judgment distinguishes strong support in mammals and birds from a realistic possibility across broader animal groups.
- Animal Consciousness ↗Stanford Encyclopedia of Philosophy (revised 2026)Conceptual distinctions, species differences and methodological limits; philosophy kept distinct from experimental results.
- Behavioral and neurophysiological evidence suggests affective pain experience in octopus ↗Robyn J. Crook, iScience (2021)Primary open-access paper; place avoidance, relief preference, controls and nerve recordings support an inference rather than a direct report of experience.
- Glutamate triggers long-distance, calcium-based plant defense signaling ↗Toyota and colleagues, Science (2018)Full original paper at a public mirror; observed plant defense signaling without a test of subjective experience.
- Learning by Association in Plants ↗Gagliano and colleagues, Scientific Reports (2016)Original pea-plant associative-learning claim; presented together with the replication dispute.
- Comment on “Lack of evidence for associative learning in pea plants” ↗Gagliano and colleagues, eLife (2020)Original authors argue that the attempted replication’s light-response conditions were unsuitable.
- Response to comment on “Lack of evidence for associative learning in pea plants” ↗Kasey Markel, eLife (2020)Primary reply records the failed replication, acknowledges reduced power and disputes the proposed setup explanation.
- Plant consciousness: review of the evidence (title shortened) ↗Mallatt and colleagues, Protoplasma (2021)Author-written review of plant-consciousness claims; title shortened to avoid the original polemical framing.
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