I was discussing the idea of 'double-punching' with a student a few days ago - and how often double-punching appears in our Longfist Forms (nearly every other movement) and how many different gongfu Forms retain double-punching! Yang Style Taijiquan retains the double-punch to each temple - although I believe it is termed 'Two Winds Pierce Ears' (双风贯耳 - Shuang Feng Guan Er) to hide the true meaning and intention (there was a lot of this type of colourful or deliberately misleading terminology to befuddle anyone attempting to steal the art).
When I was young, this move was taught to me as 'Fist Ear' (拳耳 - Quan Er) or 'Box the Ears' - even though it has absolutely NOTHING to do with striking the ears! In the local Hakka culture (where water buffaloes abound) - this movement was termed striking with the 'Water Buffalo Horns' (水牛角 - Shui Niu Jiao) or 'Sui Nyiu Gok' in the Hakka language. The two large knuckles of each closed hand 'insert' into the anatomical gaps either side of the forehead which denote the 'temples' (the place where the hair greys on a man and the passing of time is recorded). Hence 'temporal' (or the Latin 'tempus') referring to the 'passing of time', etc. Interestingly, the Chinese language term for 'temple' (as an anatomical designation) is '颞' (nie4) which can be analysed as follows:
a) Left-hand particle = 聶 (nie4) - comprised of '耳' (er3) or 'ear' repeated three times - with one ear stacked upon two ears! The simplified form is '聂' and appears to mean 'whisper into the ear'.
b) Right-hand particle = 頁 (ye4) or the anatomical human 'head' - and is comprised of:
Top element: '丆' (han3) a variant of '厂' - meaning 'cliff-top'.
Middle element: '自' (zi4) pertaining to the 'self' or 'individual' - a picture of the 'nose'.
Bottom element: ' 儿' (er2) a contraction of '兒' - an infant with an as yet still unformed fontanelle. This may refer to a 'part' or 'area' of the human head that is 'weak' (like an infant) but refers to an anatomical weakness that is retained even within an adult's mature head!
I suspect the ancient doctors (or court scholars) described the 'temple' area either side of the forehead as being like a 'third-ear', but an area which was inherently 'weak' to the touch - and which retained this 'weakness' into adulthood. The Taijiquan teachers then talk of the disembodied power (rebounding bodyweight directed by intention - fed through an aligned posture) leaving the fist and 'passing through' the thin temple area (like a strong 'breeze') into the location of the 'third ear'! Perhaps the 'awareness' generated in these parts of the brain-mind nexus (just inside the temple areas) was considered a 'type of hearing' by the ancient anatomists in China. Certainly, the capacity to 'hear' within Chinese martial arts practice involves more than just 'hearing' with the ears!