“An object may be contiguous and prior to another, without being consider’d as its cause. There is a NECESSARY CONNEXION to be taken into consideration; and that relation is of much greater importance, than any of the other two above-mention’d.”
As Hume explains it, causes are necessarily connected to their effects; the effect is necessary as a consequence (if the cause occurs, the effect must occur).
Impressions of necessary connections =
- the idea of necessary connection doesn’t come from our impressions of the qualities of individual objects, or the observable relations between objects
- Hume observes that we would never arrive at the idea of causal neccessity if we only ever saw single instances of cause and effects (only ever saw fire causing smoke once). Only from repeated instances of similar conjunctions do we form the idea of neccessary connection, and “begin to draw an inference from one to the other”
This develops Hume’s argument: the idea of causal necessity doesn’t derive solely from the sensory experience of conjoined objects. Instead, the repetitions condition the mind to add something of its own. The repetitions lead us to expect the conjoined effects when we perceive the causes, or the conjoined causes when we perceive the effects.
- e.g.: The repetitions lead us to expect that the next time we see a fire, there will be smoke billowing from it.
In other words, neccessary connection = the expectation or habit our minds have a tendancy to form when exposed to repeating pairings of cause and effects. (whenever A occurs, B will follow)
Hume calls this:
” … [Neccessity] is nothing but an internal impression of the mind, or a determination to carry our thought from one object to another”
Hume gives a subjective account of, what he considers to be, the most crucial component of causality.