Why Revolution??
Human is an incomplete being trying to find completion. He wants to do something, to be something, what is that something he don't know. He always demand change, be it of any kind, he thrives on it and why not, because change is only what he feels. Human perception is only sensitive to the change and may be that is the reason why he is not able to see his own creation- GOD, which according to him is omnipresent and ever existing. He wants to be fulfilled somehow, to reach perfection or completion through various means. It is this desire for perfection or completion which drive the society in to the revolution.
There are two ways to approach change in the society, either it is brought by the revolution fixed over a period of time, like French or American revolution or Indian national movement for that matter or by slow evolution of minds of people who are the part of society, which in a way is also a revolution (However both are interrelated as former lead to later). Basically both ways see a significant shift in the thoughts of people, structure and the working of the societies.
Society is just an abstract idea, it is just a word made up by we humans only, it does not exists really but only in the minds of the people. But what do exists is an individual, so when we are using words like society, country or nation and talking about change in it, it really does not mean anything else but it only evokes a sense of identity or nationalism and emotions like pride and love into the minds of people. At the present level of consciousness, this is the only way human could work for the development or betterment of others or society as a whole, because otherwise he is too selfish to think about collective good. May be we need a revolution to raise human consciousness, so that we could think about collective good without being imprisoned into the boundaries of nation and society.
In a way revolution is not a time and place localized phenomena, it is a dynamic process, happening every time. It may not be visible all the time and may be only its consequences are loud enough to be heard by people, but it is a process which slowly build up to the point when it brings significant alterations in the society. French revolution is not only about the abolition of monarchy and feudalism in France, but also about the issues which led to the revolution and its after-effects.
Main inspiration behind a revolution is the uncertain character of human intelligence. Human societies are not governed by any prefixed laws, but by its own consciousness, which in itself is very unpredictable, what he needs next moment he himself does not know and this uncertainty led to the all kind of revolution witnessed by mankind.
Another important factor is the desire of people, a society will never rise to revolution until and unless it is satisfied in all its desire, and there is freedom to express its in-completion. Whenever a society feel restrained or limited in its scope of action, it tries to break that limitation, and a friction is generated between the ruled and ruler which is what we call revolution. Here ruler and ruled are not specifically persons, but any kind of system or ideology or structure in society which creates this distinction. Whenever mankind will face boundaries, be it of any kind, there will be efforts to break it and those efforts will lead to the revolution.