On Proof of Concept

The present etymological consensus seems to be that L. caput, with its multitude of MoE derivatives, such as prince, principal, principle, capital, capitol, occiput, precipice, biceps et al., together with its Germanic cognates, such as Go. haubiþ, OIc. haufuð, OHG houbit, NHG Haupt, OE hēafod together derive from the root of capiō. Capacity and anticipation both derive from capiō rather than caput, as if the captive imagination needed a release for its heavy toll. As I recall I was particularly struck once by the relatedness of capiō to MoE heave, NHG heben, Erhebung, and the like, which seem to suggest the existence of an "uplifting" emotion prior to the formation of a "concept" in the brain, and prior to "the thought seizing the head". If, in the words of the poet, "Between the conception/and the creation/between the emotion/and the response/falls the Shadow" could the Shadow be a pre-condition for this, its achievement (there's another caput word)? After all, "the lengthened shadow of a man is history".

"I have it", or "I've got it", Anglophones say, and Dr. Michiel de Vaan in his Etymological Dictionary of Latin and the other Italic Languages (Brill, Leiden, 2016), produces Gothic haban, suggesting MoE have, MoDu hebben, NHG haben as belonging to the capiō group together with the "heave" verbs. He notes that words meaning 'cup' frequently become 'head', and as a result "it is not unlikely" that caput and its Germanic counterparts are derived from the root of capiō "to seize" which would point to a substratum form *kap-ut- 'cup' > 'head'. Germanic shows a vacillation between *kap-ut and *kaup-i/ut-, which may be due to some kind of u-infection. The cognate Celtic forms meaning "cup" derive from *kapuko- (OIr. cúäch, W. cawg). Late Latin 'cappa' corresponds to Italian cappuccio 'hood', and the prevailing view is that it might be related to caput. A Latin word for 'cup' is capis, -idis, which might go back as a loanword to Greek σκαφίς, -ιδος 'bowl, drinking vessel'. 

L. cāpus 'capon, castrated cock' is derived by the IEW (Pokorny) from a root *skVp- 'to cut off, hew'; from the same root L. scapulae 'shoulder blades' would be derived. Alternatively, cāpus might be connected with caper 'he-goat'. Lexikon der Indogermanischen Verben derives scapulae from a root *(s)kep- from which Gr. κόπτω 'to hit'. Scapulae may belong to Gr. σκάπτω 'to dig (out), work the earth', σκάφη 'winnow, bowl, trough, dish', also 'ship', which brings us back to capis, σκαφίς and, presumably, cāpio and caput.
...As the intellect rises from the ashes of the unconscious metaphor of the internet, so too will Homo Faber increase the dunning concept of "done" and cause the dawning of the Day of the Intellect Damage Assessor (anonymous - sans Punch & Judy graphic innuendo).