Second volume of Mill’s work on philosophy of mind clearly divides into two different parts, and I shall treat the latter part in a writing of its own. The first part continues the discussion Mill started in the first volume, that is, the analysis of common concepts pertaining to human cognition.
The first of these concepts are relational terms. You might remember from my previous post that Mill appeared to accept only monadic predication, which seems, of course, problematic for understanding relations. Mill’s solution is to suggest that relational terms like “parent-child” are actually names for a single phenomenon, consisting of two things. The different names just emphasise different aspects of this same totality. Connected to this notion is Mill’s idea that difference and opposition is necessary at least for such conscious entities as us - we do not really sense or think anything, if there is no change in our sensations and ideas. Together these ideas suggest surprisingly close tendencies with broadly Hegelian philosophers, who view the world as an necessarily interconnected system of oppositions.
Mill goes into great details classifying the various possible relations: difference and sameness of sensations, sensations as preceding one another, spatial relations of objects, temporal relations of objects, quantitative equality and inequality of objects, qualitative likeness or unlikeness of objects, same or different composition of ideas and ideas as preceding one another. A clear fault in Mill’s schema is the ignorance of relations with more than two relata. The closest Mill comes to discussing them comes with spatial relations, as he admits that even the idea of position of an object involves relations to all other objects. Still, even here Mill tries to simplify matters and concentrates on juxtaposition of two objects and such pairs like high and low or front and back.
If we inspect Mill's account of spatial relations in more detail, we find him, in a manner reminiscent of Fichte, reducing the genesis of our experience of space into muscular exertions, by which we move ourselves or things around us. In another sense, Mill’s notion of space reminds one of Leibniz, because just like him, Mill says that space is nothing but an abstraction from all the concrete positions and spatial relations between things. While Kant would object that surely space is prior to positions in it, he might approve Mill’s admission of a subjective element in our notion of space - we always associate a place with a further place, thus making our notion of space infinite.
A further peculiar element in Mill’s notion of space is that when we think of empty space, he insists, we think of something positioned in that space and then the absence of this something. This is a feature of Mill’s general theory of privative statements - he insists that thinking of absence of something, we think of both that thing and its absence (e.g., when thinking of darkness, we think of light and its absence). In case of space, this would mean that by empty space, we always mean space empty of something. Indeed, he confirms, because our experience of space is intrinsically related to the idea of something resisting our efforts, we cannot think of any space empty of everything.
Mills account of time is similar enough to his account of space that we do not have to deal with it in great detail - like space is for Mill just an abstraction of all positions, time is nothing more than just an abstraction from all successions. Reminiscent of Kantian tradition, Mill connects numbers also with successions. In other words, he points out that although numbers are used to count the greatness of synchronously existing objects, the act of counting happens through some successive operation.
Mill also investigates the notion of personal identity, especially over time, and reflection. His basic solution to this conundrum is to point out that personal identity is just a special case of any identity. Identity as such, say, of other persons, we come to know by seeing a person and remembering that we saw her earlier. Similarly, Mill says, we are always conscious of ourselves, remember being conscious of ourselves and hear testimonies of others concerning us at times, which we don’t remember.
Mill’s explanation seems flawed in many ways. Firstly, one might point out that he hasn’t ever really explained what it means of being conscious of oneself, because saying that consciousness in general is just a general name for sensations and ideas explains nothing about self-consciousness - what are we conscious about when we conscious of ourselves? Secondly, Mill’s explanation would at most tell what evidence we use to justify our assertions of self-, or indeed, any identity, but not what it means that something is identical with itself. Finally, while it is undoubtedly obvious that our assertions and experiences of self-identity are particular examples of assertions and experiences of identity, one might wonder, in the manner of Fichte, whether e.g. our experience of self-identity underlies our experience of all other identities (that is, whether we must be able to identify ourselves, before being able to identify anything else).
