Cognitive Ontology – Part 3: Episodic Memory

In this third of four blogposts, I’m going to introduce another theoretical construct from cognitive science, episodic memory, that I discuss in my book, and I will try to summarize my argument that it is a cognitive kind (and describe what kind of kind it is).

First explicitly identified and labelled by Tulving, episodic memory is often what we mean by the word “memory” in English: our capacity to retain and later recall autobiographical experiences and the mental states produced by this capacity. Tulving identified episodic memory states in terms of their phenomenology or “autonoetic” features. But even though Tulving’s characterization in terms of experiential properties has gained wide currency, there are other ways of individuating episodic memory states. One that is particularly prominent in philosophical discussions consists in the claim that it is a type of mental state that carries information about one’s personal past. The “causal theory of memory,” first proposed by Martin and Deutscher in the 1960s, holds that there is an uninterrupted causal chain between initial experience and subsequent representation that is mediated by means of a trace. But the notion of a memory trace and the positing of an enduring mental representation associated with each state of episodic memory is also common in empirical research.

The standard explanation of why actual episodic memories succeed (when they do succeed) in revealing details about the past is that they are causally linked in such a way to past events as to enable them to faithfully transmit information. Indeed, cognitive scientists explain memory errors against the background of successful memories, which they assume involve traces of past events. This inference to the best explanation does not require episodic memories to be wholly or even mostly veridical. Even if it turns out that memory is only occasionally accurate in producing specific information about past episodes, those occasions would need an explanation. (Compare: if dreams enabled us to accurately predict the future with some specificity, even sporadically, that fact would cry out for an explanation.)

If episodic memory is usually identified in terms of its etiology or phenomenology, or both, do either or both of these features give us grounds for thinking that states of episodic memory or the cognitive capacity that generates such states corresponds to a real kind? Why is it that such states share (by and large) a certain phenomenology, and what is the relationship between their etiology and their phenomenology? One prevalent theory in the psychological literature is that the phenomenal properties of episodic memories enable the thinker to distinguish episodic memories, which bear information about the past, from other mental states, such as states of imagination. On this “source-monitoring” framework, episodic memories have a distinctive phenomenology to set them apart from mental states that have a different source (e.g., imagination, inference) and are not rooted in a specific past event.

Building on a considerable body of research in the cognitive sciences, I try to make the case that the capacity of episodic memory is an evolved system whose function is (at least in part) to preserve representations of past episodes. The representational states generated by the capacity of episodic memory are characterized primarily by their etiology (the link to past episodes), but they also play a synchronic causal role in cognition, in that they enable the thinker to plan and make decisions about the future, equipped with specific information about the past. Moreover, these states are typically characterized by a distinctive phenomenology to enable the thinker to distinguish such states from those of imagination, inference, and indeed states of semantic memory, which do not have such a phenomenology.

This means that both the capacity of episodic memory and the states it produces are characterized by their synchronic and diachronic causal properties, making it a good candidate for a cognitive kind. Since the capacity of episodic memory is likely to be adaptive, it is partly etiologically individuated with reference to its evolutionary history, as are other adaptive capacities. Moreover, this means that the states produced by such a capacity are doubly etiological, since they are individuated by virtue of being traceable to past events, but they are also individuated in virtue of being outputs of the capacity of episodic memory. It should be clear from this characterization that the cognitive kind episodic memory is externalistically individuated in multiple ways, both phylogenetically (in the case of the capacity) and ontogenetically (in the case of the state).

This supports the conclusion that episodic memory is a cognitive kind whose identity conditions are grounded in etiology and environmental context, and that is reflected in the taxonomic practices of many of the research programs that study memory. This mode of individuation is evident in the context of computational inquiries (in Marr’s sense), which attempt to understand the adaptive function of episodic memory and how it enables thinkers to plan and make decisions in their social and physical environments. It is not prevalent in neuroscientific inquiries and taxonomic categories, which are primarily interested in mechanistic causal processes that are spatially circumscribed and typically take place on a more limited temporal scale.