The distinctive feature of presentative consciousness consists in the fact that it is caused by the actual presence of an individual object, whether thing, act, or state of mind, occupying a definite position in time, or in space, or in both. It is true that this object is not discerned as such, and the consciousness of it, therefore, is not fully realised without the co-operation of the representative faculties; and it is true also that representative consciousness, when complete, is exhibited in an individual unity of representation; but as the presence of the individual object is in the one case the principal, in the other only an accessory feature; and as in the one it may be regarded as the cause, in the other as the effect of the accompanying consciousness, it furnishes a sufficient principle of distinction between the two.
We shall therefore class under the general denomination of Intuitions, all those states of consciousness in which the actual presence of an object, within or without the mind, is the primary fact which leads to its recognition as such, by the subject; and from these will be distinguished, under the name of Thoughts, all those states of consciousness in which the presence of the object is the result of a representative act on the part of the subject.
In the former case, the presence of the object is involuntary ; in the latter it is voluntary. In both, the presentative and representative faculties act in combination, for this is the condition of all complete consciousness; but in the former case the object is given to, in the latter it is given by, the conscious act.
For example, while I am in the company of a friend, I have by sight an intuitive consciousness of his presence. I do not cause his presence by any mental effort of my own; it is given to me; and so long as my eye is turned towards him, I cannot help seeing him. But if I am thinking of an absent person, and endeavour to recall to mind his features, I make a voluntary effort, and thereby bring into consciousness a mental image which becomes internally now present; but the presentation is one of my own making, constructed by means of the reflective or representative faculty.
***Excerpt from Henry Longueville Mansel, B.d.. Metaphysics or the philosophy of consciousness