Engraphy and ekphory: how an English logician translated memory in 1921

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In 1921 Bertrand Russell, the author of Principia Mathematica, devotes a whole lecture to an almost unknown German zoologist. He gives his terms, his definitions, his two laws with page numbers. Then he takes them apart. But by then “engram” and “ekphory” have entered the English language, in a book people actually read.

Quotations read in the originals: Semon, Die Mneme (1904, 1920 edition) and Russell, The Analysis of Mind, Lecture IV (Gutenberg edition). At the end: what is proven and what is not.

A logician reads a zoologist

In 1921 Bertrand Russell is no ordinary philosopher. With Whitehead he has written the three volumes of Principia Mathematica, he has given his name to a paradox that forced set theory to be rebuilt, and he has just come out of prison for his pacifism. The Analysis of Mind collects fifteen lectures given in London and Peking, and its thesis is ambitious: mind and matter are not two substances, but two ways of arranging the same elements.

To hold this thesis up, one question has to be answered: what distinguishes living things from dead matter? The fourth lecture is devoted entirely to it, and the answer has a long title: Influence of Past History on Present Occurrences in Living Organisms. The author Russell chooses as his guide is Richard Semon, a Munich zoologist, author of Die Mneme (1904).

“The response of an organism to a given stimulus is very often dependent upon the past history of the organism, and not merely upon the stimulus and the HITHERTO DISCOVERABLE present state of the organism.”

— Russell, The Analysis of Mind, 1921.

The burnt child fears the fire. The burn has left no visible trace, and yet the reaction to fire has changed. A magnetised piece of steel behaves differently from an unmagnetised one, but there we can invent a hypothesis about the microscopic structure. In living things, Russell says, almost everything that is characteristic depends on this persistence of the past. And to talk about it you need a vocabulary. Semon has already built one.

Engraphy: the inscription

Semon’s definition deserves to be read in full, because it contains three things that later get lost.

“In a great many cases it can be shown that the irritable substance of the organism, whether it belongs to the kingdom of protists, of plants or of animals, after the action and cessation of a stimulus and after the return to the secondary state of indifference, is permanently altered. I call this action of stimuli their engraphic action, because it so to speak digs itself or writes itself into the organic substance. The alteration of the organic substance so produced I call the engram of the stimulus in question.”

“…gehöre er nun dem Protisten-, Pflanzen- oder Tierreich an, nach Einwirkung und Wiederaufhören eines Reizes und nach Wiedereintritt in den sekundären Indifferenzzustand dauernd verändert ist. Ich bezeichne diese Wirkung der Reize als ihre engraphische Wirkung, weil sie sich in die organische Substanz sozusagen eingräbt oder einschreibt. Die so bewirkte Veränderung der organischen Substanz bezeichne ich als das Engramm des betreffenden Reizes.” — Semon, Die Mneme, ch. II.

First: it applies to protists, plants and animals. Semon’s engram is not a memory, and consciousness has nothing to do with it. Second: the proof of the engram is the difference between two states of rest. Semon calls them the primary state of indifference (before the stimulus) and the secondary one (after the stimulus has ceased). If the two states were identical, there would be nothing to explain. Third, and most important: what gets inscribed is not an isolated stimulus but everything that was present at that moment. Russell puts it like this:

“In fact, it is not an isolated stimulus that leaves an engram, but the totality of the stimuli at any moment; consequently any portion of this totality tends, if it recurs, to arouse the whole reaction which was aroused before.”

— Russell, 1921.

This is Semon’s first mnemic law, the law of engraphy:

“All simultaneous excitements in an organism form a connected simultaneous excitement-complex, which as such works engraphically, i.e. leaves behind a connected engram-complex, which in so far forms a whole.”

“Alle gleichzeitigen Erregungen innerhalb eines Organismus bilden einen zusammenhängenden simultanen Erregungskomplex, der als solcher engraphisch wirkt, das heißt: der einen zusammenhängenden und insofern ein Ganzes bildenden Engrammkomplex hinterläßt.” — Semon, Die mnemischen Empfindungen, p. 146, in Russell’s translation.

In plain words: everything is recorded together. The smell, the noise, the light, the position of the body, what one was feeling. Not the main event, but the whole situation, as one block.

Ekphory: the recall

If engraphy is writing, ekphory is reading. But with a property no archive has: you do not need the whole key. Russell:

“When two stimuli occur together, one of them, occurring afterwards, may call out the reaction for the other also. We call this an “ekphoric influence,” and stimuli having this character are called “ekphoric stimuli.” In such a case we call the engrams of the two stimuli “associated.””

— Russell, 1921.

And here is the second mnemic law, the law of ekphory:

“The partial return of the energetic situation which formerly worked engraphically operates ekphorically on a simultaneous engram-complex.”

“Ekphorisch auf einen simultanen Engrammkomplex wirkt die partielle Wiederkehr derjenigen energetischen Situation, die vormals engraphisch gewirkt hat.” — Semon, Die mnemischen Empfindungen, p. 173, in Russell’s translation.

Russell’s example is the smell of peat smoke: you smell it, and an occasion on which you smelt it before comes back to mind. The same smell does not produce the same memory in another man who has not had that experience. So the cause of the memory is not the smell alone: it is the smell plus the past occasion.

Semon catalogues several kinds of ekphory: one triggered by the passing of time (the daily and yearly cycles of plants and animals), one triggered by a stage of development, and the vicarious kind, in which a stimulus different from the original takes its place. And he draws from it a corollary about amnesia which, in his book, stands in the table of contents of chapter VI:

“Most amnesias are based not on loss of engrams, but on the impossibility of ekphorising, at the time, engrams that are still perfectly intact.”

“Die meisten Amnesien beruhen nicht auf Verlust von Engrammen, sondern auf der Unmöglichkeit, die noch vollkommen intakten Engramme zur Zeit zu ekphorieren.” — Semon, Die Mneme, ch. VI.

The reason is the second law read backwards: if the present situation is too different from the one in which the writing took place, the recall does not happen. The drunk, the feverish, the person in strong agitation cannot find things they otherwise know well. The trace is intact; what is missing is the condition for reading it.

Russell’s move: keep the facts, drop the hypothesis

Up to this point Russell is a faithful populariser. Then he acts as a logician. The engram, he notes, is a hypothesis: nobody has seen it. Semon himself admits as much, writing that for now nothing more can be said than that it must consist in some material alteration of the body. So Russell splits the two laws into what is observed and what is supposed:

“These two laws together represent in part a hypothesis (the engram), and in part an observable fact. The observable fact is that, when a certain complex of stimuli has originally caused a certain complex of reactions, the recurrence of part of the stimuli tends to cause the recurrence of the whole of the reactions.”

— Russell, 1921.

And he proposes to do without the engram. In its place, mnemic causation: a causal law in which the proximate cause is not only the present event, but the present event together with a past event. The laws of psychology, he says, do not have the form “X now causes Y now”, but:

“”A, B, C,… in the past, together with X now, cause Y now.””

— Russell, 1921.

A, B, C are the mnemic cause, X the occasion, Y the reaction. A “disposition”, such as being able to answer “Paris” to the question about the capital of France, is nothing actual in the mind: it is the mnemic portion of a causal law. And Semon’s two laws are condensed into one, which Russell writes in capitals:

“IF A COMPLEX STIMULUS A HAS CAUSED A COMPLEX REACTION B IN AN ORGANISM, THE OCCURRENCE OF A PART OF A ON A FUTURE OCCASION TENDS TO CAUSE THE WHOLE REACTION B.”

— Russell, 1921.

From this definition there also follows a definition of biography that is worth isolating:

“We might, in fact, define one chain of experience, or one biography, as a series of occurrences linked by mnemic causation. I think it is this characteristic, more than any other, that distinguishes sciences dealing with living organisms from physics.”

— Russell, 1921.

The brain is necessary, not sufficient

Russell closes by weighing the two hypotheses, and here he is honest to the end. Against mnemic causation as the ultimate explanation: mnemic phenomena are found in physiology and in plants too, and nobody wants a causation that jumps across time inside physiology. In favour of the engram: brain injuries destroy memory. But this argument, he observes, is weaker than it looks.

“What we know is that memory, and mnemic phenomena generally, can be disturbed or destroyed by changes in the brain. This certainly proves that the brain plays an essential part in the causation of memory, but does not prove that a certain state of the brain is, by itself, a sufficient condition for the existence of memory.”

— Russell, 1921.

To prove sufficiency one would have to see the difference between the brain of a man who speaks English and that of a man who speaks French, between one who has seen New York and one who has not. “It may be that the time will come when this will be possible, but at present we are very far removed from it.” Russell adopts the engram as a working hypothesis, but keeps the other door open, because “it often turns out important to the progress of science to remember hypotheses which have previously seemed improbable.”

Why it matters

In 1904 Semon writes in German, for physiologists. In 1916 Bleuler brings engram and ekphory into the most widely read psychiatry textbook in the German language. In 1921 Russell does the third thing: he brings them into English, in a book by a famous author, with definitions, laws, editions and page numbers. In the same year the English translation of Die Mneme also comes out, from the same publisher, Allen & Unwin, and Russell points to it in a footnote.

After 1921, then, an educated English-speaking reader no longer needs German to meet the idea that every situation is recorded in full, that a fragment is enough to recall it, and that most amnesias are intact traces that cannot be read. In 1950 these three ideas reappear, under the same name of engram, in a book that cites neither Semon, nor Bleuler, nor Russell.