  It is another crucial assumption of Proclus’ epistemology that all souls share the same logoi (Elem. Theol. § 194–195). In terms of concept-formation this entails that psychic concepts, once they are grasped correctly, are universal, objective, and shareable (see Helmig (2012) 13–24). Moreover, if all souls share the same logoi, and these logoi are the principles of reality (see above), then by grasping the logoi souls come to know the true principles or causes of reality. Already Aristotle had written that to know something signifies to know its cause (Met. A 3, 983a25–26 and An. Post. I 2, 71b9–12). In his Commentary on Plato’s Timaeus, Proclus introduces an interesting distinction. Taking his start from the problem of how we can recognise certain objects, he considers the example of an apple. The different senses tell us that there is something sweet, red, even, with a nice smell. And while common sense (koinê aisthêsis) can distinguish the different impressions of the special senses, only opinion (doxa) is capable of saying that the object there on the table is an apple. Doxa is able to do this, because it has access to the innate logoi of the soul. However, as Proclus explains (In Tim. I 248.11 ff.), opinion only knows the ‘that’ (hoti), that is, it can recognize objects. Discursive thought (dianoia), on the other hand, also knows the ‘why’ (dihoti), that is, the causes of something. This distinction can also be rephrased in terms of concepts, implying a distinction between factual concepts that allow us to identify or recognise certain objects, and concepts that fulfil an explanatory role. On the whole, Proclus’ reading and systematisation of Plato’s doctrine of learning as recollection makes Platonic recollection not only concerned with higher learning, since already on the level of object recognition we employ concepts that originate from the innate logoi of the soul (Helmig (2012) 299–333).