Do we have a faculty of memory because we store intact copies of our memories, or do we have memories because we exercise our faculty of memory by continually reactivating and reinventing new versions of our memories? Is faithfulness to the past guaranteed by the complete integrity of the stored memories, or by the quality with which we exercize the faculty of memory? This ancient question has gained an acute relevance at the present time in the new context brought about by digital technologies: on the one side there is a hubris of the digital which leads to conserving and stocking everything; on the other, a way of practising computerized information where every item of content is reinvented each time it is consulted. This article comes back to the basic conditions of possibility of memory, in order to privilege a dynamical conception according to which memory is a permanent exercise where one takes hold of objects in order to interpret them as traces, thereby reinventing the past by the witness of these objects. What is at stake is the reasoned critique of this mode of reinvention.