  Thus ideas of pleasure or pain are the causes of these motivating passions.  Not just any ideas of pleasure or pain give rise to motivating passions, however, but only ideas of those pleasures or pains we believe exist or will exist (T 1.3.10.3).  More generally, the motivating passions of desire and aversion, hope and fear, joy and grief, and a few others are impressions produced by the occurrence in the mind either of a feeling of pleasure or pain, whether physical or psychological, or of a believed idea of pleasure or pain to come (T 2.1.1.4, T 2.3.9.2).  These passions, together with the instincts (hunger, lust, and so on), are all the motivating passions that Hume discusses.  