Power acquired by violence is only a usurpation, and lasts only as long as the force of him who commands prevails over that of those who obey.
Interpretation
Violent power is illegitimate and unstable, reliant on force rather than true authority.
Denis Diderot's quote emphasizes that power gained through violence is not legitimate; it is merely a seizure of control that can easily crumble when the coercive force is diminished. True authority is built on consent and the willingness of others to follow rather than through intimidation or fear.
In practice
In a speech on leadership, you might quote Diderot to emphasize the importance of ethical governance.
The arbitrary rule of a just and enlightened prince is always bad. His virtues are the most dangerous and the surest form of seduction: they lull a people imperceptibly into the habit of loving, respecting, and serving his successor, whoever that successor may be, no matter how wicked or stupid.
This root [the potato], no matter how much you prepare it, is tasteless and floury. It cannot pass for an agreeable food, but it supplies a food sufficiently abundant and sufficiently healthy for men who ask only to sustain themselves. The potato is criticized with reason for being windy, but what matters windiness for the vigorous organisms of peasants and laborers?
Do you see this egg? With this you can topple every theological theory, every church or temple in the world.
There are three principal means of acquiring knowledge... observation of nature, reflection, and experimentation. Observation collects facts; reflection combines them; experimentation verifies the result of that combination.
In order to get as much fame as one's father one has to much more able than he.
All abstract sciences are nothing but the study of relations between signs.
If there are no dogs in Heaven, then when I die I want to go where they went.
How long had he been doing what was necessary instead of what was right? In a fair world they would be one and the same.
Comfort and luxury are usually the chief requirements of life for your ego - its top priorities tend to be accumulations, achievements, and the approval of others.
How can a doctor judge a woman's sanity by merely bidding her good morning and refusing to hear her pleas for release? Even the sick ones know it is useless to say anything, for the answer will be that it is their imagination.
The end of labor is to gain leisure.
He cannot "tempt" to virtue as we do to vice. He wants them to learn to walk and must therefore take away His hand; and if only the will to walk is really there He is pleased even with their stumbles.
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