A quick brush-up, courtesy mainly of Wikipedia: Historically, society has been divided up into estates of social hierarchy. In medieval times, the First Estate was the monarchy and the clergy, the Second Estate included the nobles, the Third Estate consisted of bourgeoisie (merchants) and commoners (peasants or non-landowners. In some countries, the non-landowners were the Fourth Estate, or were left outside the estate system, having no power or voice. In England, the system evolved to the House of Lords and the House of commons.
Theoretically, we see this tradition in the evolution of democratic government into separation of powers of the legislature, administration, and judiciary branches, with the voting citizens corresponding to a Fourth Estate. Sometimes the press and media are referred to as the Fourth Estate of society, although outside of government.
In reality, we seem to have returned to the times of the original Three Estates of the medieval world: a First Estate resembling a monarchy and clergy (party loyalists), a Second Estate of "Nobles" of Industry - indistinguishable from the First Estate, a Third Estate of Middle Class workers, and a mixture of commoners with little or no Estate status. In modern terms, "estate" refers to a private ownership; and that, essentially, is what our government has become.
What is totally overlooked in these concepts of government are the formidable "estates" and universities representing the intellectual disciplines, knowledge, and achievements of civilization. Surely, the sciences and arts and their associated practices should have a commanding place in government, advising us how to live for our greatest mutual and lasting benefit. Why do we have these disciplines if we don't use them to govern us wisely? To fulfill the purposes of our constitution and of mankind, they should be at the heart of government instead of private interests. If it were so, perhaps we wouldn't need government as
presently structured.