Memory

Wittgenstein once wrote, “If I say rightly, ‘I remember it’, the most different things can happen, and even merely this: that I say it” (1974: §131). Wittgenstein is drawing our attention to the heterogeneity of the category of memory, and the corresponding unlikelihood that the variegated phenomena we refer to with the term “memory” will be amenable to any unied explanatory model. Recent cognitive science acknowledges, indeed reinforces, this heterogeneity with the common tripartite distinction between procedural, semantic, and episodic memory. Procedural memory is the mnemonic component of learned – as opposed to xed – actions patterns: to have procedural memory is to remember how to do something that one has previously learned. For this reason, it is sometimes referred to as knowing how (Ryle 1949) or habit memory (Bergson 1908; Russell 1921). The most obvious examples of procedural memory are embodied skills such as riding a bicycle, playing the piano, or skiing. Procedural memory has nothing essentially to do with conscious recall of prior events: one can, in principle, know how to do something while having completely forgotten learning to do it. Semantic memory is memory of facts (Tulving 1983). It is not immediately clear that this category is genuinely distinguishable from the category of belief. What is the difference between, for example, believing that Ouagadougou is the capital of Burkina Faso and remembering this fact? Beliefs are dispositional, rather than occurrent, items (Wittgenstein 1953: 59). Neither beliefs nor memories need be consciously recalled or apprehended by a subject in order to be possessed by that subject. Therefore it is difcult to avoid the conclusion that semantic memories are simply a subset of beliefs. Not all beliefs qualify as semantic memories. If I perceive that the cat is on the mat, and form the belief that the cat is on the mat on this basis, it would be very odd to claim that I remember that the cat is on the mat. However, all semantic memories do seem to be beliefs: the claim that I remember that P without believing that P seems to be contradictory. And the most obvious explanation of this is simply that to remember that P is the same thing as to believe that P. Episodic memory, sometimes called “recollective memory” (Russell 1921), is a systematically ambiguous expression. Often it is used to denote memory of prior

episodes in a subject’s life (Tulving 1983, 1993, 1999; Campbell 1994, 1997). However, it is also sometimes taken to denote memory of prior experiences possessed by that subject. For example, Locke understood (episodic) memory as a power of the mind “to revive perceptions which it has once had, with this additional perception annexed to them, that it has had them before” (1975 [1690]: 150). In a similar vein, Brewer denes episodic memory as a reliving of one’s phenomenal experience from a specic moment in their past, accompanied by a belief that the remembered episode was personally experienced by the individual in their past (1996: 60). The ambiguity embodied in the concept of episodic memory, then, is that between the episode experienced and the experience of the episode. This ambiguity is signicant but can be accommodated in a sufciently sophisticated account of episodic memory. Suppose you fell out of a tree when you were eight years old. It is, let us suppose, a fact that you did so. However, when you recall this episode, it is not in the manner typical of recalling a fact – in the same way that you might recall that Ouagadougou is the capital of Burkina Faso. You do not recall it even in the manner you might recall personal facts about yourself – such as the fact that you were born on a certain date. You recall this episode in a certain distinctive manner. That is, you recall this past episode by way of certain experiences you had, or purport to have had, when the episode took place. You recall the episode of falling from the tree through, or by way of, the feelings of vertiginous terror you experienced, or take yourself to have experienced, during that episode. In particular, you experience the episode as something that happened to you, or as an event otherwise presented to you in some specic experiential way (for example, you can remember the episode of someone else falling out of a tree). In short, that episodic memory involves recall of past episodes is not, by itself, sufcient to distinguish it from semantic memory – for these episodes can also be understood as a species of fact. What is distinctive of episodic memory is the way in which facts are presented: they are presented by way of experiences. And these experiences, in turn, are presented as ones that the subject had at the time of the episode. It is this sort of structured double mode of presentation that seems to essentially characterize episodic remembering. In such remembering, episodes are presented via experiences, and these experiences are presented – rightly or wrongly – as ones that occurred at the time of the episode. The dening characteristic of episodic memory, therefore, is its mode of presentation of facts. In veridical episodic memory, we remember both the episode and the experience. What is crucial is that we remember the episode via the experience: by the way the experience presents the episode and the way the experience that presents the episode is in turn presented. This has one clear and important entailment: the distinction between episodic and semantic memory is one of degree not kind. What would the memory of your falling out of the tree amount to if it were not presented by way of experiences that are themselves presented as occurring at the time of the episode? It would, it seems, amount to little more than the apprehension of the fact that you fell out of tree at some point in the past – akin to remembering that you were born on a certain date. Generally, episodic memory would be gradually transformed into semantic memory if

its specic and concrete experiential content becomes sufciently abstract and attenuated that its situational specicity is lost (Rowlands 1999: 126). If this is correct, then the common claim that semantic memory is found only in humans (Donald 1991: 152) might be difcult to sustain. Procedural memory is a sub-species of knowledge. Semantic memory is a sub-species of belief. To the extent that memory engenders a specic and distinctive set of philosophical and scientic issues, these turn on the core concept of episodic memory – even though this is a range rather than rigid concept. Accordingly, this paper will focus primarily on this latter form of memory.