"Upon this I mounted into the censorium of his brain, to learn from the spirit of consciousness, which you call self, the cause of so uncommon a change, as it is contrary to the fundamental rules of our order, ever to give up an heart of which we once get possession."
— Johnstone, Charles (c.1719-c.1800)
I found the spirit very busy, though I thought somewhat odly employed: she was running over a number of niches, or impressions, on the fibres of the brain, some of which I observed she renewed with such force, that she almost effaced others, which she passed over untouched, though interspersed among them. The sight of me seemed to suspend her works a moment, but as if that pause was only to recover strength, she instantly renewed her labour with greater assiduity.
I looked at her, my desire to know the meaning of what she was doing, and to signify the cause of my visit, to which she returned me this answer in a glance, that interrupted not her work.
(I see you wonder, that I speak of this spirit, though the self of a man, as if it was a female; but in this there is a mystery; every spirit is of both sexes, but as the female is the worthier with us, we take our denomination from that.)
You are surprised, (looked she) to find me so earnestly engaged, in work which you do not understand; but in this work consists my very essence. This place, where we are, is the seat of memory; and these traces, which you see me running over thus, are the impressions made on the brain by a communication of the impressions made on the senses by external objects. --These first impressions are called ideas, which are lodged in this repository of the memory, in these marks, by running which over, I can raise the same ideas, when I please, which differ from their first appearance only in this, that, on their return, they come with the familiarity of a former acquaintance.
How this communication though is made, I cannot so well inform you; whether it is by the oscillation of the nervous fibres, or by the operation of a certain invisible fluid, called animal spirits, on the nerves; no more than I can explain to you, how my touching these marks, on this material substance the brain, can raise ideas in the immaterial mind, and with the addition of acquaintance beside; for these are matters not quite fully settled among the learned.
All I know is, that the thing is agreed to be so by some, or other, or all of these means; and that my whole employment, and end of being, is to touch them over, and acknowledge their acquaintance thus; without my doing which, a man would no longer continue the same person, for in this acquaintance, which is called consciousness, does all personal identity consist.
See Chrysal; or the Adventures of a Guinea. Wherein are exhibited Views of several striking Scenes, with Curious and interesting Anecdotes of the most Noted Persons in every Rank of Life, whose Hands it passed through in America, England, Holland, Germany, and Portugal. By an Adept. (London: Printed for T. Beckett, 1760). <Link to Hathi Trust>