g. mention of one flat leads to an enquiry about others in the block and thirdly cause or effect -thinking of a wound makes us think of the pain that will follow. Hume believed that it is these laws, and these laws only that underlie all connections in the mind. He believed in connections in the mind because there is always a methodical and regular train of events, and that a break in these trains is always noticed. For example in a conversation, if someone breaks a certain train of thought, everyone would notice and the train breaker is likely to admit that he had been lead away from another train of ideas.
However, there are many problems with this, and the no-self argument. Firstly resemblance, without a mind as an agent to note a resemblance, there is no way that resemblance between two ideas can be responsible for the association. In order for sense datum to add to something more than a stream of consciousness, there must be some kind of unity between the data - a "unity of apperception" as called by Kant.
Problems with continuity in time and space are that it is acceptable that ideas, as mental images, can be related in time but that existing just as ideas they can not be related. Cause and effect also comes with its own problems. Hume, himself is against induction. So to say that cause and effect is one of the main processes of the mind, must have seemed obvious to Hume himself. To say that because you have seen something happen before, like a wound causing pain it will happen again, does not logically follow. Also to say that a wound is followed by pain is not the same as saying that the idea of a wound is followed by the idea of pain, it is difficult to even say that any mental images can come into cause and effect at all.
The other problem is that Hume accepts the idea that all we can directly be aware of in perception is our own ideas, now according to Hume's own Copy Principle, this ought to be provable by a single impression, but if we can not even be sure of our impressions, how can we trust any of our ideas, unless to render them void.
