in Thorau’s Journal:

As I planted there, wandering thoughts visited me, which I have now forgotten.

My senses were busily suggesting them, though I was unconscious of their origin. E. g., I first consciously found myself entertaining the thought of a carriage on the road, and directly after I was aware that I heard it. No doubt I had heard it before, or rather my ears had, but I was quite unconscious of it, — it was not a fact of my then state of existence; yet such was the force of habit, it affected my thoughts nevertheless, so double, if not treble, even, are we. Sometimes the senses bring us information quicker than we can receive it. Perhaps these thoughts which run in ruts by themselves while we are engaged in some routine may be called automatic. I distinctly entertained the idea of a carriage, without the slightest suspicion how it had originated or been suggested to my mind. I have no doubt at all that my ears had heard it, but my mind, just then preoccupied, had refused to attend to it. This suggests that most, if not all, indeed, of our ideas may be due to some sort of sensuous impression of which we may or may not be conscious.