'If we speak of the Mind as a series of feelings, we are obliged to complete the statement by calling it a series of feelings which is aware of itself as past and future: and we are reduced to the alternative of believing that the Mind, or Ego, is something different from any series of feelings, or possibilities of them, or of accepting the paradox that something which _ex hypothesi_ is but a series of feelings, can be aware of itself as a series. 'The truth is that we are here face to face with that final inexplicability at which, as Sir W. Hamilton observes, we inevitably arrive when we reach ultimate facts; and in general one mode of stating it only appears more incomprehensible than another, because the whole of human language is accommodated to the one, and is so incongruous with the other, that it cannot be expressed in any terms which do not deny its truth. The real stumbling-block is perhaps not in any theory of the fact, but in the fact itself. The true incomprehensibility perhaps is, that something which has ceased, or is not yet in existence, can still be, in a manner, present: that a series of feelings, the infinitely greater part of which is past or future, can be gathered up as it were into a single present conception, accompanied by a belief of reality. I think, by far the wisest thing we can do is to accept the inexplicable fact, without any theory of how it takes place; and when we are obliged to speak of it in terms which assume a theory, to use them with a reservation as to their meaning[8].' Memory an ultimate fact! It is the first that stares us in the face on beginning to philosophise, and it haunts us through all our subsequent speculations. It is the 'dweller on the threshold' of philosophy, which unless we overcome will overcome us, and frustrate our magic. The passage quoted does not show Mill's usual candour and consistency. His philosophy has broken down on an essential point, and he is reluctant to admit it. He tries to throw the blame on other things, and recommends that those who think with him should maintain a discreet silence on the subject of memory, or if obliged to speak of it do so in ambiguous language. That is hardly honest, and is bad philosophical practice. What we know or think we know we may leave alone--it will not run away; it is what we are conscious of not knowing that should receive our persistent attention.