I am interested in the question of whether thinking must be an activity of a subject. Is it true that thinking has no reality without being a mode of the subject? Could it be possible that there is some theory of thinking according to which thinking does not require a subject？I do not expect a full answer to these questions here but I would really appreciate it if someone could give me some directions (e.g. what books/journal articles/encyclopaedias should I read?). I tried the Stanford Encyclopedia of Philosophy but did not find a relevant entry on this topic. Perhaps someone could tell me what the correct entry/keyword for searching is. Thanks very much.
It might help if I add the following context to the question:
The question originates from the Lichtenbergian objection against Descartes' Cogito Argument as Lichtenberg claims that a conscious thinking can at best imply that there is thinking going on but there might not be a thinking subject associated.