One half of seven is 3½ and seven is a significant number metaphysically so, from that point of view, it represents the peak of a cycle split into seven.

Also this:

One half of seven, 3½, is also a conspicuous number in Revelation: two witnesses are given power to prophesy 1,260 days, or exactly 3½ years, according to the Hebrew year of 360 days (11:3); the witnesses are then killed, and their dead bodies lie in the streets of Jerusalem for 3½ days (11:9); the "woman clothed with the sun" is protected in the wilderness for 1,260 days, or 3½ years (12:6); Gentiles tread the holy city underfoot for 42 months, or 3½ years (11:2); and the beast is given authority to continue for 42 months, or 3½ years (13:5)

Source: Book of Revelation - Wikipedia

Hello fred ... for us humans the number 3 1/2 (three and a half) corresponds to a powerful spring-like energy in the form of 3 1/2 coils situated in the sacrum bone ... this energy can be induced to awaken using a resonant frequency ... for example a system of numbers corresponding to the number of coils ... karma 35, 350, 3500, 35000 etc. ... here is more information;

http://en.wikipedia.org/wiki/Kundalini

According to the symbolism of numbers in the bible

http://catholic-resources.org/Bible/Numbers.htm

3 1/2 signifies things still in progress, things imperfect or not completely developed ... this idea corresponds perfectly to a "sleeping coil" that needs to be aroused

From a sacred geometry point of view, 3 is the perfect triangle symbolizing source energy (god if you like) and 4 is a square symbolizing a perfect planet earth ... 3 1/2 is in between suggesting an unfinished, imperfect ever evolving physical world in which we live ... unraveling the coil provides a link between the perfect triangle source energy and the four square perfect planet earth ... have a great day :)

the yin yang symbol as seven part and can be split in 2 that would also be 3.5! so 3.5 is part of the whole of seven!one part going up and one coming down!one positive and one negative!