52-56.) The only comment that appears needful here is, that Hume has attached somewhat too exclusive a weight to that repetition of experiences to which alone the term "custom" can be properly applied.

The proverb says that "a burnt child dreads the fire"; and any one who will make the experiment will find, that one burning is quite sufficient to establish an indissoluble belief that contact with fire and pain go together.
As a sort of inverted memory, expectation follows the same laws; hence, while a belief of expectation is, in most cases, as Hume truly says, established by custom, or the repetition of weak impressions, it may quite well be based upon a single strong experience.

In the absence of language, a specific memory cannot be strengthened by repetition.

It is obvious that that which has happened cannot happen again, with the same collateral associations of co-existence and succession.

But, memories of the co-existence and succession of impressions are capable of being indefinitely strengthened by the recurrence of similar impressions, in the same order, even though the collateral associations are totally different; in fact, the ideas of these impressions become generic.
If I recollect that a piece of ice was cold yesterday, nothing can strengthen the recollection of that particular fact; on the contrary, it may grow weaker, in the absence of any record of it.