156. The question which he mainly dealt with may be stated in general terms as that of the relation between the mind and the external world. Under this general statement, however, are covered several distinct questions, the confusion between which has been a great snare for philosophers--questions as to the relations _(a)_ between a sensitive and non-sensitive body, _(b)_ between thought and its object, _(c)_ between thought and something only qualified as the negation of thought. The last question, it will be observed, is what the second becomes upon a certain notion being formed of what the object of thought must be. Upon this notion being discarded a further question _(d)_, also covered by the above general statement, must still remain as to the relation between thought, as in each man, and the world which he does not make, but which, in some sort, makes him what he is. In what follows, these questions, for the sake of brevity, will be referred to symbolically. Confusions involved in Locke’s materialism. 157. Locke’s doctrine of matter, as we have seen, involves a confusion between _(a)_ and _(b)_. The feeling of touch in virtue of an intellectual interpretation--_intellectual_ because implying the action of the mind as (according to Locke) the source of ideas of relation--becomes the idea of solidity, _i.e._ the idea of a relation between bodies in the way of impulse and resistance. But the function of the intellect in constituting the relation is ignored. Under cover of the ambiguous ‘idea,’ which stands alike for a nervous irritation and the intellectual interpretation thereof, the feeling of touch and conception of solidity are treated as one and the same. Thus the true _conceived_ outwardness of body to body--an outwardness which thought, as the source of relations, can alone constitute--becomes first an imaginary _felt_ outwardness of body to the organs of touch, and then, by a further fallacy--these organs being confused with the mind--an outwardness of body to mind, which we need only kick a stone to be sure of. Meanwhile the consideration of question _(d)_ necessitates the belief that the real world does not come and go with each man’s fleeting consciousness, and no distinction being recognised between consciousness as fleeting and consciousness as permanent, or between feeling and thought, the real world comes to be regarded as the absolute opposite of thought and its work. This opposition combines with the supposed externality of body to mind to give the notion that body is the real. The qualities which ‘the mind finds inseparable from body’ thus become qualities which would exist all the same ‘whether there were a perceiving mind or no,’ and are primarily real; while such as consist in our feelings, though real in so far as, ‘not being of our own making, they imply the action of things without us,’ are yet only secondarily so because this action is relative to something which is not body. Then, finally, by