As we reach the half-way point of Mercury's retrograde period, take a moment to reflect on what's happening here. Mercury (and Venus) being between the orbit of Earth and Sun appear to behave differently from the other planets. They have phases, like the Moon, and indeed if you're lucky enough to get a look at them through a telescope at certain points of the cycle, they appear as crescents rather than full disk.
Dane Rudhyar divided Mercury's cycle into four phases. The waxing phase – from inferior to superior conjunction – he called Promethean; the waning – from superior conjunction back to inferior – he called Epimethean. Prometheus was, of course, the Titan who stole fire from the gods and gave it to humans; his less famous brother is really only remembered through the story of Pandora's Box, so he's not looked upon very affectionately. Their names mean 'forethought' or 'foresight' and 'afterthought' or 'hindsight' respectively, although I don't think these terms fully explain the different manifestations of Mercury.
A waxing Mercury is adolescent: impetuous, eager and impulsive, but somewhat immature. They act first and think later. However, a waning Mercury is more reflective: they're concerned with long-term objectives and they like to weigh up all the evidence before making a decision.
At the beginning of the Mercury retrograde period, Mercury and the Sun are moving towards each other, to meet again at inferior conjunction. This is bringing a cycle of roughly four months to an end, using the insights gained to construct a new vision for the future. The nineteenth century mystic Ramakrishna, who taught that all religions led to the same goal – God – is an example of an Epimethean retrograde Mercury. (He had practised several different faiths himself, including Christianity and Islam).
Following the inferior conjunction, the still-retrograde Mercury begins to draw away from the Sun. As it does so, it looks to the future, eager to break free from social conventions or whatever else might seek to restrain its enthusiasm for the new. Aldous Huxley, author of 'Brave New World' – where anything old was considered to be of no value – is an example of a Prometheus retrograde Mercury.