Can Panpsychism be Tested?

(Thanks to National Library of Medicine for the image)

This is the question I get asked most on social media: Can panpsychism be tested? Here’s the answer: No. You can’t do experiments to test whether an electron or a field has feelings.

But nor can you do experiments to test whether a fish, or a bird, or another human being has feelings. I can’t look inside your brain and see your feelings. If your methodological position is: ONLY BELIEVE IN THINGS WE CAN DEMONSTRATE TO EXIST THROUGH PUBLIC OBSERVATION AND EXPERIMENT, then you won’t believe in consciousness, because consciousness is not publicly observable.

It’s not just that it’s not publicly observable with the naked eye, or through a microscope. Of course, scientists theorise about loads of things that can’t be directly observed, such as fundamental particles. But these things are postulated to explain what is publicly observable. Feelings, in contrast, are not postulated to explain observable facts about the brain. We know that consciousness exists not from empirical observation but from being conscious – from being immediately aware of our own feelings and experiences.

(TRIGGER WARNING: I’m about to bring in some nuance. I appreciate some people find that difficult, so feel free to stop reading if you need to. Maybe make a cup of tea, have a break, and come back to this when you feel mentally prepared.)

There are things we can do experimentally to build a case that certain things are conscious. Here’s what we do:

1. Scan subject X’s brain; the physical processes in the brain are publicly accessible.

2. Trust X’s testimony about their private feelings and experiences that can’t be accessed through public observation and experiment.*

3. Try to correlate the unobservable experiences with the observable physical processes in the brain.

4. Extrapolate beyond the human case.

Note that this is already quite a departure from the standard scientific method. In the standard scientific method, the whole task is to explain the data of public observation and experiment. But in the scientific investigation of consciousness, we are bringing in a radically different data-point – privately known feelings – and then trying to correlate observable processes with those privately known feelings. It’s worth trying to do this. But there is a huge amount of disagreement even in the human case, and the further we get from the human case, the more the more method breaks down. Eric Schwitzgebel has a great paper arguing that this method fails to establish whether or not a snail is conscious, never mind an electron.

I don’t want to be too pessimistic. Maybe one day we’ll get strong consensus on a universal theory of the physical correlates of consciousness, and that theory will tell us whether or not electrons are conscious. But my justification for panpsychism comes from a different place.

What we have just been discussing is the attempt to use a semi-experimental method to establish correlational facts about which physical processes go along with conscious experiences. But there’s a further question:

• Why is physical activity – of any kind – correlated with conscious experience?

Because consciousness is not publicly observable, this is not a question that can be answered by an experiment. Answering this question is always going to involve inference to the best explanation. Perhaps a helpful (although imperfect) analogy might be attempts to establish facts of ancient history. The past is dead and gone, and so we can’t do an experiment to establish whether or not Caesar crossed the Rubicon. But we can make an inference to the best explanation from current evidence. Likewise, we can start from the data-point that consciousness is correlated with physical activity (even if we can’t completely pin down the specifics) and the try to establish which of the following three hypotheses best explains this:

1. Physicalism – Consciousness emerges from physical activity.

2. Panpsychism – Physical activity emerges from the interactions of simple forms of consciousness.

3. Dualism – Physical activity and consciousness are different things, but tied together by fundamental laws of nature.

It’s funny that people always demand to know how we test panpsychism, but never demand to know how we test physicalism. This reveals that they’re not at first base in understanding that consciousness is a unique phenomenon that requires a unique approach. Because it’s not publicly observable – directly or indirectly – we’re not going to be able to account for it by just applying the standard methods of physical science. Until we get this, we won’t make progress on consciousness.

I haven’t told you here why I think the second explanation above is the one to go for, but you won’t have trouble funding my answer online if you’re interested. But I hope I’ve at least explained why the question ‘How do you test it?’ misses the point.

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*We can also to an extent rely on external markers of consciousness. But even here we’re not postulating feelings to explain an observable occurrence, in the way we postulate particles to explain empirical data. This is a nuanced but crucial distinction.