Mahr & Csibra's (M&C's) article is full of thought-provoking ideas but also contains serious conceptual and empirical difficulties. Here we articulate three challenges that may severely undercut M&C's claim that remembering is for reason-giving communication. The first challenge is conceptual. According to M&C, episodic memory consists of an epistemic attitude to the effect that the content of the mental simulation provides us with information that has been obtained firsthand. However, there are certain kinds of mental simulations that provide us with firsthand information and yet wouldn't qualify as episodic memories. Consider the following case. You are snowboarding down a steep hill and nearly avoid a pine tree you somehow failed to notice. An immediate, involuntary counterfactual simulation comes to mind: “Had I been a meter to my right,” you think, “I would have been dead now.” This automatic “subjunctive replay,” as Hofstadter (Reference Hofstadter1982) playfully calls it, provides us with firsthand information as to what would have happened had a minor deviation from reality occurred instead of what actually was the case.
Indeed, some philosophers have argued that these kinds of imaginative simulations constitute knowledge (e.g., Williamson Reference Williamson2007; Reference Williamson, Kind and Kung2016). Nevertheless, you wouldn't say that you remember hitting the tree a minute ago: You just imagined it could have happened. Therefore, it looks as though there is a species of episodic counterfactual simulation (De Brigard Reference De Brigard2014a; De Brigard & Giovanello Reference De Brigard and Giovanello2012; De Brigard et al. Reference De Brigard, Addis, Ford, Schacter and Giovanello2013) that is quasi-experiential, event specific, epistemically generative, autonoetic, and past-directed that nonetheless is not a memory. Perhaps M&C could defend their account by arguing that because these kinds of episodic counterfactual simulations do not represent actual past events but rather closely possible past events, they fail to meet the past-directedness requirement of episodic memories. But this response won't do, for the same occurs with many of our ordinary reconstructed memories, as they normally represent past events with some degree of deviation from what actually happened in the past. An account of episodic memory that cannot include these normally distorted reconstructed memories would fail to capture the psychological reality of remembering.
Their proposal also faces serious empirical challenges. First, if episodic memory is for a particular kind of reason-giving communicative interaction, as M&C claim, then we should expect to see individuals with episodic memory deficits – for instance, patients with amnesia due to medial temporal lobe damage or individuals with severe depression – exhibiting difficulties when carrying out such communicative interactions. Unfortunately, not only do M&C fail to provide neuropsychological support for this observation, but also there seems to be enough evidence against its being the case. For example, patient HM, a notoriously famous case of episodic autobiographical amnesia, did not seem to have trouble engaging in all sorts of reason-giving communications about past events, as long as these events were in the recent past and HM was able to entertain them in working memory (see Corkin Reference Corkin2013 for plenty of examples of these sorts of reason-giving communicative exchanges between HM and others).
Of course, HM had trouble generating reasons whose contents depended on his capacity to bring back to mind remote past events. But this just shows that episodic memory is necessary for generating some contents – that is, contents about remote first-person past experiences – that may feature in reason-giving communicative exchanges about the past; in no way does it show that such is its function. HM's machinery to engage in the communicative reason-giving transactions, which M&C claim that remembering is for, was, in fact, intact. What HM lacked was the capacity to generate the contents that would feature in a subset of such reasons, namely, those about remote past experiences. Failing to generate mental contents that can feature in reason-giving communicative interactions is, at best, very weak evidence for saying that the psychological process that produces such contents evolved for the purpose of reason-giving communication. Consider an analogy: cortically blind people cannot generate visual contents that could feature in reason-giving exchanges about objects in their visual field. Should we take this as evidence for the claim that vision evolved so we can engage in reason-giving exchanges with conspecifics about objects in our visual field? This claim seems preposterous, even for evolutionary psychology.
The final challenge we put forth is somewhat related. It is reasonable to suppose that, with the development of language and complex social interactions, humanity faced a new fitness problem: how to keep track of others' assertions and testimonies. Because such assertions and testimonies often involved past events, it seems reasonable that humans developed strategies to temporally keep track of the veracity and reliability of people's assertions and testimonies. From the pressure to exercise this sort of “epistemic vigilance” onto others – M&C argue – arose episodic memory. But why should this particular kind of tracking be that for which episodic memory evolved? After all, our ancestors presumably had to temporally track all sorts of different items that were critical for survival: predators, poisonous plants, dangerous areas, glucose rich fruits, and so on. Wouldn't it be more reasonable to say that episodic memory evolved to help us keep track of such fitness-enhancing items, and that once there, our ancestors were able to capitalize on an already available system for temporal tracking of past events and redeploy it to track, among other things, assertions and testimonies? It seems very unlikely that the fitness-enhancing item episodic memory evolved for was something as culturally dependent and as phylogenetically recent as reason-giving assertions and testimonies. It seems much more parsimonious to think that this kind of tracking came about because we already had the kind of episodic memory that allows us to track fitness-enhancing stuff in general, of which conspecifics' reliable testimonies are just one part.
Mahr & Csibra's (M&C's) article is full of thought-provoking ideas but also contains serious conceptual and empirical difficulties. Here we articulate three challenges that may severely undercut M&C's claim that remembering is for reason-giving communication. The first challenge is conceptual. According to M&C, episodic memory consists of an epistemic attitude to the effect that the content of the mental simulation provides us with information that has been obtained firsthand. However, there are certain kinds of mental simulations that provide us with firsthand information and yet wouldn't qualify as episodic memories. Consider the following case. You are snowboarding down a steep hill and nearly avoid a pine tree you somehow failed to notice. An immediate, involuntary counterfactual simulation comes to mind: “Had I been a meter to my right,” you think, “I would have been dead now.” This automatic “subjunctive replay,” as Hofstadter (Reference Hofstadter1982) playfully calls it, provides us with firsthand information as to what would have happened had a minor deviation from reality occurred instead of what actually was the case.
Indeed, some philosophers have argued that these kinds of imaginative simulations constitute knowledge (e.g., Williamson Reference Williamson2007; Reference Williamson, Kind and Kung2016). Nevertheless, you wouldn't say that you remember hitting the tree a minute ago: You just imagined it could have happened. Therefore, it looks as though there is a species of episodic counterfactual simulation (De Brigard Reference De Brigard2014a; De Brigard & Giovanello Reference De Brigard and Giovanello2012; De Brigard et al. Reference De Brigard, Addis, Ford, Schacter and Giovanello2013) that is quasi-experiential, event specific, epistemically generative, autonoetic, and past-directed that nonetheless is not a memory. Perhaps M&C could defend their account by arguing that because these kinds of episodic counterfactual simulations do not represent actual past events but rather closely possible past events, they fail to meet the past-directedness requirement of episodic memories. But this response won't do, for the same occurs with many of our ordinary reconstructed memories, as they normally represent past events with some degree of deviation from what actually happened in the past. An account of episodic memory that cannot include these normally distorted reconstructed memories would fail to capture the psychological reality of remembering.
Their proposal also faces serious empirical challenges. First, if episodic memory is for a particular kind of reason-giving communicative interaction, as M&C claim, then we should expect to see individuals with episodic memory deficits – for instance, patients with amnesia due to medial temporal lobe damage or individuals with severe depression – exhibiting difficulties when carrying out such communicative interactions. Unfortunately, not only do M&C fail to provide neuropsychological support for this observation, but also there seems to be enough evidence against its being the case. For example, patient HM, a notoriously famous case of episodic autobiographical amnesia, did not seem to have trouble engaging in all sorts of reason-giving communications about past events, as long as these events were in the recent past and HM was able to entertain them in working memory (see Corkin Reference Corkin2013 for plenty of examples of these sorts of reason-giving communicative exchanges between HM and others).
Of course, HM had trouble generating reasons whose contents depended on his capacity to bring back to mind remote past events. But this just shows that episodic memory is necessary for generating some contents – that is, contents about remote first-person past experiences – that may feature in reason-giving communicative exchanges about the past; in no way does it show that such is its function. HM's machinery to engage in the communicative reason-giving transactions, which M&C claim that remembering is for, was, in fact, intact. What HM lacked was the capacity to generate the contents that would feature in a subset of such reasons, namely, those about remote past experiences. Failing to generate mental contents that can feature in reason-giving communicative interactions is, at best, very weak evidence for saying that the psychological process that produces such contents evolved for the purpose of reason-giving communication. Consider an analogy: cortically blind people cannot generate visual contents that could feature in reason-giving exchanges about objects in their visual field. Should we take this as evidence for the claim that vision evolved so we can engage in reason-giving exchanges with conspecifics about objects in our visual field? This claim seems preposterous, even for evolutionary psychology.
The final challenge we put forth is somewhat related. It is reasonable to suppose that, with the development of language and complex social interactions, humanity faced a new fitness problem: how to keep track of others' assertions and testimonies. Because such assertions and testimonies often involved past events, it seems reasonable that humans developed strategies to temporally keep track of the veracity and reliability of people's assertions and testimonies. From the pressure to exercise this sort of “epistemic vigilance” onto others – M&C argue – arose episodic memory. But why should this particular kind of tracking be that for which episodic memory evolved? After all, our ancestors presumably had to temporally track all sorts of different items that were critical for survival: predators, poisonous plants, dangerous areas, glucose rich fruits, and so on. Wouldn't it be more reasonable to say that episodic memory evolved to help us keep track of such fitness-enhancing items, and that once there, our ancestors were able to capitalize on an already available system for temporal tracking of past events and redeploy it to track, among other things, assertions and testimonies? It seems very unlikely that the fitness-enhancing item episodic memory evolved for was something as culturally dependent and as phylogenetically recent as reason-giving assertions and testimonies. It seems much more parsimonious to think that this kind of tracking came about because we already had the kind of episodic memory that allows us to track fitness-enhancing stuff in general, of which conspecifics' reliable testimonies are just one part.