The March edition of Investigación y Ciencia, the Spanish edition of Scientific American, published a translation of my Scientific American article ‘Galileo’s Big Mistake‘. In June it published my answers to a couple of questions from readers. Below is the English translation of the questions and my replies.
First Letter: In “Galileo’s Big Mistake,” Philip Goff argues that, in order to scientifically confront the problem of consciousness, one should overcome Galileo’s scientific viewpoint based on limiting the explanation of the natural world to its quantitative properties. This conclusion is based on the fact that consciousness only manifests itself when the subject confronts the qualitative —not quantitative— properties of natural entities.
However, when considering the natural world from the perspective of a conscious subject, all of it boils down to consciousness, since even the mathematical laws used by Galileo to quantify natural phenomena are nothing but ideal entities: they need a subject who thinks about them, and as such they don’t belong to the realm outside the subject. In fact, if the philosopher George Berkeley was right with his motto “esse est percipi,” nature itself wouldn’t exist in the absence of a conscious subject perceiving it.
In summary, what a subject can know about consciousness will always be limited to their own conscious activity. And it doesn’t seem possible for the empirical science to establish what consciousness is by means of experiments carried out outside consciousness itself, beyond the mere correlations mentioned by the author between the various mental tasks and the neural activity of certain brain regions.
JOSÉ ENRIQUE GARCÍA PASCUA; Torrecaballeros, Segovia (Spain)
My Reply: I certainly agree that all knowledge of mediated through consciousness, and that consciousness is the only thing we know for certain is real. But if I only believe in things I’m utterly certain of the existence of, then I’ll be quickly led to solipsism: the view that my conscious mind is the only thing that exists. We cannot know for certain that other people exist, or, as Bertrand Russell observed, whether the world was created more than five minutes ago. In order to live life, we need to trust our memories, and we need to trust that the people our sensory experiences seem to put us in touch with are real.
It could be that these other people are non-physical conscious minds, as George Berkeley supposed. But the trouble with Berkeley’s view is that we require some explanation of the commonalities and regularities in our experiences. Why is it that when my wife and I look in the same direction, we both have an experience of a table. Berkeley postulated a constantly intervening God to make sense of this, but this seems to me an extravagant and inelegant postulation. Michael Pelczar and Donald Hoffman try to make sense of this without God, and their work is really interesting. However, it seems to me much more simple and straightforward to postulate a shared physical world to account the commonalities and regularities in our experience. Why do my wife and I both experience a table? Because there’s a table out there in physical reality, and it causes our experiences by impacting on our bodies.
However, in order to avoid Galileo’s Big Mistake, I adopt a panpsychist, rather than a materialist, conception of physical reality. There is a physical world out there, but it’s infused with consciousness. This is the positive bit of my book ‘Galileo’s Error: Foundations for a new Science of Consciousness.’
Second Letter: The general idea behind Goff’s article stems from the thesis implied by the example of the tree: “When a tree comes crashing down in a forest, the crashing sound isn’t really in the forest, but in the consciousness of an onlooker. No onlooker, no consciousness, no sound.” However, I don’t agree with such viewpoint: the sound produced when the tree crashes doesn’t depend on whether an observer is present or not, since the pressure waves exist anyway, also in the absence of an observer.
In Galileo’s time, the existence of neurons and brain functionalities wasn’t known, and therefore it didn’t make sense to talk about modelling internal perceptions of any kind. But today we have mathematical models that are able to determine the effect of the sound when, in the form of neural pulses, it reaches the various brain regions and activates them in specific ways. Therefore, and at least up to this point, a scientific model based on mathematics would still be valid.
The fact that we are still ignorant about the origin of consciousness doesn’t mean that consciousness cannot be modelled mathematically. It’s true that such a modelling may be impossible, but we won’t know until we learn about the nature of consciousness and try to detect it and measure it.
JOSÉ MEDINA FERRER
My reply: It depends what you mean by ‘sound’. If you mean ‘vibrations in the air’, then, yes, there is sound out there, independent of the observer. But if you mean ‘the qualitative sound we seem to encounter in our experience,’ then I would disagree that this exists out there in the physical world.
Galileo’s contemporaries had crude theories of brain mechanisms. We certainly have a much better understanding of the mechanisms of the brain. But none of this has made the slightest difference with respect to the problem of consciousness. The problem is that physical science, whether the science of Galileo’s time or are own, works with a purely quantitative vocabulary, and you can’t capture the qualities of consciousness in these terms. The language of physical science can’t convey to a colour blind neuroscientist what it’s like to see red. I agree that we can model consciousness in mathematics, and such models are useful. But they abstract away from the qualities involved in consciousness, and hence only tell a partial story. It’s a bit like how mathematical models in economics are very useful, even though they abstract away from the specific details about individuals and their labour.
I believe we are currently going through a phrase of history in which we are blown away by the success of physical science, and this leads us to think that physical science is the only source of knowledge, that everything else is superstition. The irony is that physical science has been so successful precisely because it was designed to be a partial description of reality, abstracting away from those aspects of reality that can’t be captured in mathematics.