Helgoland by Rovelli, Erica (ebook reader below 3000 .txt) 📗

and interactions fluctuate. What we call “stone,” furthermore, is a stratification of meanings in our thoughts, evoked by the interaction between ourselves and that galaxy of punctiform relative physical events. “Simple matter” splits apart into complex strata and suddenly seems much less simple. And perhaps the gulf between simple matter and the evanescent unraveling of our spirit appears to be a little less impassable.

If the fine grain of the world is made of material particles that have just mass and motion, it seems difficult to reconstruct our perceiving and thinking complexity from this amorphous grain. But if the fine grain of the world is better described in terms of relations, if nothing has intrinsic properties except in relation to other things, perhaps in this physics we can better find elements able to combine in a comprehensible way, to be the basis of those complex phenomena that we call our perceptions and our consciousness. If the physical world is woven from the subtle interplay of images in mirrors reflected in other mirrors, without the metaphysical foundation of a material substance, perhaps it becomes easier to recognize ourselves as part of that whole.

Someone has suggested that there is something psychic in all things. The argument is that since we have consciousness and are made up of protons and electrons, then the electrons and protons should already have a kind of proto-consciousness.

I don’t find such arguments and such “pan-psychism” persuasive in the slightest. It is like saying that since a bicycle is made of atoms, then each atom must be proto-cyclist. Our mental life needs the existence of neurons, sensory organs, a body, the complex elaboration of information that occurs in our brains; all the evidence suggests that without this we have no mental life.

But there is no need to attribute proto-consciousness to elementary systems in order to get around a frozen “simple matter.” It is enough to have observed how the world is better described by relative variables and their correlations. This allows us to be released from the prison of a blunt opposition between the objectivity of matter and mental life. The rigid distinction between a mental world and a physical one fades. It is possible to think of both mental and physical phenomena as natural phenomena: both products of interactions between parts of the physical world.

In this, the last chapter of the book before its conclusion, I offer a few humble suggestions in this difficult direction.

WHAT DOES “MEANING” MEAN?

We human critters live in a world of meanings. The words of our language “mean” something. The word “cat” means a cat. Our thoughts “signify”; they occur in our brain, but if we think of a tiger, we are referring to something that is not in our brain: the tiger may be anywhere out there in the world. If you are reading this book, you see the image of the lines on the page or screen. “To see” is something that happens in your brain, and yet the lines seen are “out there.” A process takes place in your brain that refers to the lines on the paper. These, in turn, have a meaning: they refer to my thoughts while writing, which, in turn, refer to the you who is reading whom I am now imagining . . .

A technical term for “referring to something” in our mental processes (promoted by the German philosopher and psychologist Franz Brentano) is “intentionality.” Intentionality is an important aspect of the notion of meaning and our whole mental life. There is a close relationship between what happens in thoughts and what happens “outside” of thoughts: what thoughts mean. There is a close relation between the word “cat” and a cat; between a road sign and what the road sign signifies.

There seems to be nothing of any of this in the natural world. A physical event in itself “means” nothing. A comet travels respecting the laws of Newton, but it does not do so by reading road signs . . .

If we are part of the physical world, this world of meanings must emerge from the physical world. How? What is the world of meanings, in purely physical terms?

Two concepts bring us close to an answer: information and evolution, even if neither is enough to comprehend what “meaning” is in physical terms. Let’s consider them both.

In the information theory of Claude Shannon, information is only counting the number of possible states of something. A USB memory stick has a quantity of information, expressed in bits or gigabytes, which indicates how many different ways its memory can be arranged. The number of bits does not know the meaning of what is in the memory; it does not even know whether the content of the memory means something or is just noise.

Shannon also defines the notion of relative information, which is the one I used in the previous chapters: a measure of the physical correlation between two variables. Two variables have “relative information” if they can be in fewer states than the product of the number of states that each can be in.

This notion of “relative information” is purely physical. It is central in quantum physics: relative information is generated by the interactions that weave the world. Notice that it connects two different things, just as meaning does. But it isn’t enough to understand meaning; the world swarms with correlations, but the vast majority of these do not signify or mean anything. To understand meaning we need something else.

The discovery of biological evolution, on the other hand, has allowed us to build some bridges between concepts that we use when speaking about animate things and concepts that we use for the rest of nature. In particular, it has clarified the biological—and in the final analysis, physical—origin of such notions as utility and relevance.

The biosphere is formed by structures and processes that are useful for the continuation of life: we have lungs in order to breathe; eyes with which to see. Darwin’s