Ragged Clown

It's just a shadow you're seeing that he's chasing…


Mind is to brain as software is to hardware

You might want to skip this one if you are not interested in philosophy. You might enjoy my favourite posts here instead. My essay is not too hard to follow though. Maybe you’ll enjoy it too.

Why am I writing this? 

I’ve been interested in the philosophy of mind for a while. It’s kind of the reason I started studying philosophy with the Open University in the first place. I was lucky enough to have a philosopher as my tutor in my first module (Hi, Dr Stuart!) and, as the module came to an end, I asked him ‘Would a physicalist say that information is physical?’ and he gave me a thousand-word answer that amounted to ‘it depends’. Dr Stuart suggested I write my own thoughts down. I wanted to get them down before we study philosophy of mind in my current Open University module so, here goes.

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Information and the physical world

Philosophers from Plato to René Descartes to David Chalmers have attempted to explain the nature of the mind and its relationship to the body. I will claim that the very idea of mind comes with too much baggage and superstition to provide much clarity and we can make better progress toward understanding if we start with something simpler. In this essay, I will examine the relationship between information and the physical world and show that the relationship between information and the medium it is stored on offers a useful starting point to understanding what the brain does. I will conclude by comparing the information processing that happens in a computer with the information processing that happens in the brain. I will start by explaining what I mean by information.

Information has various meanings in science, maths and philosophy but I will use this commonsense definition:

Information consists of a collection of data points that convey meaning.

A data point is a fact about the world that can be expressed in various ways: notes on a piece of paper; bits and bytes on a CD ROM; drawings in the sand; tunes from a trombone and countless other media. The particular arrangement of data points contains and conveys information to any information processing system that is able to understand what it means. As an example, consider the lyrical poem, She Walks in Beauty by Lord Byron (1788 – 1824).

She walks in beauty, like the night
Of cloudless climes and starry skies;
And all that’s best of dark and bright
Meet in her aspect and her eyes:
Thus mellowed to that tender light
Which Heaven to gaudy day denies.

Lord Byron, 1814

In this poem, Byron uses words and phrases to describe one of his many paramours and each phrase captures a data point about the woman and what she means to Byron. Combining these phrases into a poem, Byron tells us that he has met a beautiful woman and she reminds him of a cloudless night. The experience has meaning to Byron and, referring back to my definition of information, Byron conveys the meaning to us via a collection of data points. 

We are currently seeing Byron’s poem on a computer screen or, perhaps, on a printed page but we can also hear the poem spoken aloud and we can store it in the indentations of a CD ROM. At one point, the poem existed only in the brain of Lord Byron. The poem itself seems to exist independently of any particular medium. In a similar way, other examples of information — Pythagoras’s Theorem, Beethoven’s Fifth Symphony and the adventures of the Italian plumbers in Super Mario Bros — can be reproduced on papyrus, played on a kazoo or enjoyed on a Nintendo Wii. They share with Byron’s poem the ability to be transmitted via or stored on several different media. This raises questions about the nature of information and how it is related to the physical world and I will begin my investigation with Descartes’s conception of the mind.

René Descartes (1596 – 1650) was one of the first philosophers in the modern era to consider the separation between the mind and the body. For Descartes, we humans are made from two fundamentally different kinds of substance: our bodies are made of physical stuff and our minds are made of mental stuff, where mental stuff is a non-physical substance that does not have physical attributes like weight or colour and does not take up space. This division of the world into physical stuff and mental stuff has come to be known as dualism. For Descartes, the mind is a thinking-thing that is separate from the body and survives the body after our death. Mind is closely related to Christianity’s concept of a soul and Descartes uses the two terms interchangeably (Descartes, 1748). However, I would argue that terms such as mind, soul and self are holdovers from a time when most people believed in an immaterial soul implanted by God and that they generate more heat than light in our investigation. Furthermore, such terms are unnecessary. However, this idea of dualism has relevance to the definition of information which I will address below.

Putting aside his supernatural claims, Descartes noted that the mind and body are made of different stuff—the body is made of physical stuff while the mind is not. We can make a similar claim about information. Information seems to simultaneously exist on a physical substrate while being independent of any particular substrate. Does information depend on the physical substrate for its existence? And is information therefore physical? As with Descartes’s concept of mind, information is clearly not made of the same stuff as physical objects. Does this mean that there are two different kinds of substance? I claim that it makes no difference what name we give to the distinction but will argue that the analogy between information and mind is useful when we try to understand the distinction between mind and body. The relationship between software and hardware makes for another useful analogy and I will investigate this in the next section.

The relationship between information and the medium it is stored on is similar to the relationship between a computer program (the software) and the computer it runs on (the hardware). A computer program is a sequence of instructions for a computer to execute and, just as Byron’s poem can exist as either writing on a page or as vibrations in the air, a computer program can exist on a variety of media. It requires a computer to execute but the program itself can take several different forms.

To illustrate, consider this simple program written in the programming language Ruby and try to guess what it will do.

3.times { print ‘Ho! ‘ }

Even if you know very little about computers or programming, you can probably guess that it results in the following output.

Ho! Ho! Ho!

In other words, you were able to receive the instructions from the written text, interpret the meaning and generate the output in the little voice in your head. A computer would do the same. In fact, the software that executes Ruby programs is called an interpreter. A Ruby interpreter will, exactly as you did, receive the instructions, interpret the meaning and generate the output. Also, as with Byron’s poem, a Ruby program seems to exist independently of any medium. It can be written on a piece of paper, stored on a CD Rom or downloaded from the Internet. It can be executed by a variety of hardware devices: it will run on your computer, on your phone, in your head or even in your doorbell if you have one of those fancy ‘smart doorbells’. One could argue that the program depends on its physical substrate—the computer that it runs on—just as the poem does and, in principle, you could trace the execution of the program down to the central processing unit (CPU) of the host computer, through the silicon in the CPU’s transistors and down to the electrons crossing junctions inside the transistors but, in practice, that would be almost impossible to do. Besides, you don’t need to do that. You can give a complete description of what the program will do from the set of instructions and an understanding of the rules of the interpreter. As with the poem, the program seems to have an existence that is independent of the medium it is stored on and, as with the poem, we can understand the program as information: it is a collection of data points that convey meaning.

We now have two examples that demonstrate the relationship between information and the physical objects that contain it. I will now consider a third: the brain also stores information (as with the poem) and interprets and executes instructions (as with the computer program). Note that I am not claiming the brain is a computer (that claim comes with too much baggage and is a distraction from my thesis). Rather, I am claiming that the analogy between the software and the hardware that it runs on is useful in understanding what the brain does and, in the next section, I will explore this analogy further.

Compared to the brain, a computer is quite simple: information is fed into a CPU which interprets the information and produces output and the information may be stored in memory for later use. Computer hardware is typically not altered by the software that it executes or the information that it stores. In a similar way, the information in the brain is stored in billions of neurons. A neuron is a type of cell that interacts with its neighbours via electrochemical messages. Each neuron is connected to thousands of its neighbours and each connection is called a synapse. The brain contains trillions of synapses and, while the exact mechanism is not yet entirely understood, information is stored in those synapses (Ramón y Cajal, 1894). However, unlike a computer, when the brain receives information, the brain itself is altered as new synapses form. There is not quite the strong distinction that exists between computer hardware and software but, nevertheless, the hardware of the brain stores information just as a computer does. Somewhere in those trillions of synapses are the words from Byron’s poem. 

The brain can process information and follow instructions too. Consider what happens when you multiply two numbers.

Seven threes are twenty-one, carry the two, five threes are fifteen plus two. That’s one hundred and seventy-one.  

Somewhere in those trillions of synapses are the instructions for multiplying two numbers and the ability to follow those instructions. Just like a computer, the brain stores information and it processes information. However, processing information is just one of the things that the brain does. The brain also regulates our heartbeat and moves our limbs; it receives data from our eyes, ears and touch and, from that data, builds models of the world; it can imagine a moonlit night at the beach and it can remember last night’s romantic encounter. The brain can do all those things but what the brain is and what the brain does are separate concepts. Philosophers often refer to the latter as mind but I would argue that terms such as mind and consciousness and self are distractions from a time before neuroscience and computer analogies could provide simpler explanations without mysterious and supernatural ideas from the middle ages.

In summary, as with Byron’s poem and the computer program, the information and the instructions for processing it seem to have an existence that is separate from the neurons and synapses that do the storing and processing. It’s not too fanciful to imagine that we could find another substrate (silicon, perhaps?) that could perform the same task and I will explore this idea in a separate essay.

In this essay, I have established that information is a real thing in the world that is separate from but dependent on the physical world that makes it possible. Information can take the form of a poem, a symphony, a computer program or, crucially for my argument, a thought in the brain. I have left a few ideas dangling—I have not explained what I mean by meaning or understanding, for example. Neither have I addressed the topic that I am tantalisingly heading toward (for reasons that I make clear below): an explanation of how the brain creates conscious experiences. I will address these ideas in a separate post.


I am enjoying my essays for my Open University class but I’ve been frustrated that they are quite shallow and I can’t dig as deep as I want to dig. Charlotte suggested that I write two essays—one for my tutor and one for myself—but I found that I am so done with the topic by the time I submit my essay that I am ready to move on to the next subject. I thought I’d try writing the essay for myself first before I’ve even read the materials for this topic.

I’ve skipped the subject of consciousness for now, partly because my essay was already getting long and partly because it strays dangerously close to the topic of my next assignment. I’ll return to it when the assignment is done.

I’ve been interested in the nature of consciousness for a while but all the explanations I have read seem to me to be heading down the wrong track. I think even starting with the idea of consciousness is a mistake because consciousness means so many different things to different people and the idea leads us astray. I believe a simple understanding of information and its relation to what happens in the brain will give us a firmer foundation when we come to consider the (ahem) harder problems. 

I skipped referencing because it is soul-destroying. All the ideas are my own except where otherwise noted. I also skipped the usual objection-making because my essay was already getting long. I’ll come back to it. 

Comments, objections and suggestions are welcome.

Brain is a computer
The brain as a computer in the style of Vincent Van Gogh – Dall·E