Recently, a reader asked an interesting question about memories:

You/we say that memories cannot be found in the brain as if they are part of another entity like the soul. Can they be stored outside the body? Might it be we just don’t have the correct way to measure them? Hard to know?

So here’s my reply:

I think we make a mistake when we try to understand memories as things that can be stored. It doesn’t make any sense to talk about the “storage” of non-physical entities. Philosophers like to call that a category error. If we put memories in the wrong category of entities, we may develop mistaken ideas about them.

Knowing and memory

Knowing is an ability to do something, and memories are our retained knowledge. I remember how to play chess and I remember my grandmother. That means I retain the ability to play chess and I retain the ability to recognize my grandmother. So that’s all memory is — retained knowledge.

It makes no sense to speak of retaining abilities or knowledge in terms of ‘storage’ as if they were stored in a computer, any more than it makes sense to speak of losing them in terms of ‘deleting’ them from a computer. We can be able or unable to do something. We can remember or not remember how to do it. But the concept of storage is just irrelevant to ability and memory.

The term “storage” for memories is a metaphor — an image drawn from a different type of activity that makes it easier to talk about this one. Metaphors are fine if we understand that they are merely word pictures. For example, “My heart longs for home” is a fine metaphor, but it would be silly to look for my longing for home on my ECG tracing.

But what about brain damage?

Readers might ask, “Can’t brain damage ‘delete’ memories?” Certain kinds of brain damage may inhibit my ability to play chess or recognize my grandmother. Brain damage can inhibit all sorts of things. But that doesn’t mean that my “stored” memories have been “deleted” by brain damage in the same way that erasing a hard drive can delete the information stored on it. Storage and deletion are concepts that can be applied meaningfully to the state of electrons on a hard drive but they can’t be applied meaningfully to human memory. There they are just metaphors.

If brain damage interferes with my ability to play chess or recognize my grandmother, it merely means that due to brain damage I no longer know how to play chess or know what my grandmother looks like.

How does memory work?

Some neuroscientists think that memory is encoded in brain states in some kind of simple correspondence between memory and molecules or action potentials (although I doubt that this is the case). But even then, what would be stored or deleted would be the engram, not the memory itself. By analogy, if I delete all instances of the number ‘4’ from my hard drive, my actions affect only the electrons, not the number 4 itself.

Once again, to speak of storing memories is like saying that I keep my dreams in my back pocket. It’s a nice metaphor, but nothing more. For example, it makes no sense to say that I lost my dreams because I had a hole in my pocket!

Another view of memory and the mind

A clearer way of talking about memory and the mind derives from the work of philosopher Ludwig Wittgenstein (1889–1951). For example, from the Internet Encyclopedia of Philosophy,

The similarities between the sentences “I’ll keep it in mind” and “I’ll keep it in this box,” for instance, (along with many others) can lead one to think of the mind as a thing something like a box with contents of its own. The nature of this box and its mental contents can then seem very mysterious. Wittgenstein suggests that one way, at least, to deal with such mysteries is to recall the different things one says about minds, memories, thoughts and so on, in a variety of contexts.

What one says, or what people in general say, can change. Ways of life and uses of language change, so meanings change, but not utterly and instantaneously. Things shift and evolve, but rarely if ever so drastically that we lose all grip on meaning. So there is no timeless essence of at least some and perhaps all concepts, but we still understand one another well enough most of the time.

Duncan J. Richter, Ludwig Wittgenstein (1889—1951), Internet Encyclopedia of Philosophy

Like all forms of understanding, memory is immaterial.

Neuroscientist M.R. Bennett and philosopher P.M.S. Hacker have written about it extensively in their superb book Philosophical Foundations of Neuroscience (Wiley-Blackwell 2003). If you’re interested in this topic, that’s a great place to start because it’s relatively accessible for a technical book on philosophy and neuroscience.

For a great short introduction to Wittgenstein with a focus on the mind and human nature from a more philosophical and less neuroscientific perspective, Hacker’s Wittgenstein (The Great Philosophers Series) is superb. A very readable and broader introduction to Wittgenstein’s philosophy is Anthony Grayling’s Wittgenstein: A Very Short Introduction.

Wittgenstein’s work—particularly his and later work—is indispensable to understanding the mind. He shows how a clear analysis of language dissolves many of the conundrums that have plagued philosophy of mind and neuroscience.

You may also wish to read: Where, exactly, is memory stored in the brain? The hippocampus of the brain is important for memory formation but memories are immaterial and are not really “stored” anywhere. Memories during near-death experiences, when the mind is not in touch with the brain, are often clear, precise, and comprehensive. (Michael Egnor)