Christian Unity?

While visiting Eric, Christian asked why there are so many denominations. When I read this piece I thought it brought some light to his question.

Christian Unity
“It is very important to have a clear notion of the nature of the Christian unity spoken of in the Scriptures, and to understand in what this ‘true bond of unity’ consists, so often alluded to and earnestly dwelt on by our Sacred Writers.
The unity they speak of does not mean agreement in doctrine, nor yet concord and mutual good will; though these are strongly insisted on by the apostles. Nor, again, does it mean that all Christians belong, or ought to belong to some one society on earth. This is what the apostles never aimed at, and what never was actually the state of things, from the time of Jerusalem. The Church is undoubtedly one, and so is the human race one; but not as a society or community, for, as such, it is only one when considered as to its future existence. The teaching of Scripture clearly is, that believers on earth are part of a great society (church or congregation) of which the Head is in heaven, and of which many of the members only ‘live unto God’, or exist in his counsels,-- some having long since departed, and some being not yet born. The universal Church of Christ may therefore be said to be One in reference to HIM, its supreme Head in heaven; but it is not one community on earth. And even so the human race is one in respect of the One Creator and Governor; but this does not make it one family or one state. And though all men are bound to live in peace, and to be kindly disposed towards every fellow creature, and all bound to agree in thinking and doing whatever is right, yet they are not at all bound to live under one single government, extending over the whole world. Nor, again, are all nations bound to have the same form of government, regal or republican, etc. That is a matter left to their discretion. But all are bound to do their best to promote the great objects from which all government is instituted, -- good order, justice, and public prosperity.
And even so the Apostles founded Christian churches, all based on the same principles, all sharing common privileges,-- ‘One Lord, one faith, one baptism,’ – and all having the same object in view, but all quite independent of each other. And while, by the inspiration of Him who knew what was in Man, they delineated those Christian principles which Man could not have devised for himself, each Church has been left, by the same divine foresight, to make the application of those principles in its symbols, its forms of worship, and its ecclesiastical regulations; and, while steering its course by the chart and compass which his holy Word supplies, to regulate for itself the sails and rudder, according to the winds and currents it may meet with.
Now I have little doubt that the sort of variation resulting from this independence and freedom, so far from breaking the bond, is the best preservative of it. A number of neighboring families, living in perfect unity, will be thrown into discord as soon as you compel them to form one family, and to observe in things intrinsically indifferent, the same rules. One, for instance, likes early hours, and another late; one likes the windows open, and another shut; and thus, by being brought too close together, they are driven into ill-will, by one being perpetually forced to give way to another. Of this character were the disputations which arose about church music, the posture of the communicants, the colors of a ministers dress, the time of keeping Easter, etc.” Richard Whately, D.D.