The origin of memories is thought to be found in sensory perception. This conception is central to how the memory sciences characterize encoding. This paper considers how novel memory traces can be formed independently of external sensory inputs. I present a case study in which memory traces are created without sensory perception using a technique I call optogenetic memory implantation. Comparing this artificial process with normal memory encoding, I consider its implications for rethinking the causal chain that leads to remembering.

Martin and Deutscher’s causal theory of remembering holds that a memory trace serves as a necessary causal link between any genuine episode of remembering and the event it enables one to recall. In recent years, the causal theory has come under fire from researchers across philosophy and cognitive science, who argue that results from the scientific study of memory are incompatible with the kinds of memory traces that Martin and Deutscher hold essential to remembering. Of special note, these critics observe, (...) is that a single memory trace can be shaped by multiple past experiences. This appears to prevent traces from underwriting Martin and Deutscher’s distinction between remembering an event and merely forming an accurate representation of it. This paper accepts such criticisms of the standard causal theory and, through considering the phenomenon forgetting through repetition, raises several others. A substantially revised causal theory is then developed, compatible with the thesis that individual memory traces are shaped by multiple past experiences. The key strategy is to conceive of episodic remembering not as the simple retrieval and projection of a static memory trace, but as a complex quasi-inferential process that makes use of multiple forms of information and cues—“prop-like” memory traces included—in generating the experience known as episodic remembering. When remembering is understood as a multi-componential process, there are a variety of ways in which a representation of the past may be appropriately causally dependent upon a prior experience of the event remembered. (shrink)