The clemency is the polar opposite of anger - the disease of the tyrant - of which Seneca describes the causes and suggests therapy in another writing, the De ira : if we want to get the better sull'ira, she should not be to get the better of us . We will start to win only when the hide and will prevent the burst of the outside; In fact - says Seneca - if we allow to flow, it dominates us: we must therefore hide in the deepest of our remote chest, it must be dragged because there drag; we must fight all his clues and its manifestations: it should soften the voice, loosen up, hold the face and gradually the inside and outside will comply.
With his treatise sull'ira, Seneca distanced from positions Peripatetic, inclined to give vent to anger and not to contain it. The philosopher counselor can help train the Prince of quell'autodominio, which is a guarantee of proper control over others.

The collaboration with Nero lasted until 62, when the killing of butter, which had joined Seneca in the position of director, the clemency of the prince dissolved. Forced to political impotence, philosophy becomes for Seneca Street redemption. The loss of political space is compensated by the extension in time of the effectiveness of its action, exercised with writing.
E 'in this period that Seneca composed his most important philosophical writings, and in particular some dialogues De otio, De tranquillitate minds , De Providentia and, above all, the Quaestiones naturales (where Seneca looks with great sympathy to scientific progress, provided it is subjugated to the rule of reason) and 124 Epistulae morales ad Lucilium , a collection of letters (perhaps with a recipient fictional) in which we find in a nutshell the whole thought Seneca.
The starting point and 'recognize that it is impossible to struggle against fate and that the fundamental error is to attribute value to what depends on it: " we are all slaves of destiny: someone is bound with a long chain' gold, the other with a short chain and base metal. But who cares? the same prison encloses all are chained even those who keep chained others ... all life is slavery. We must therefore get used to their condition, complaining as little as possible, and taking all the benefits that it can offer "(De tranquillitate minds) ."

According to Seneca, then, virtue is not closed to anyone and for this aspect also the slaves are men. He, however, 'does not draw the conclusion that a slave virtuous should also be freed from slavery in legal terms, as this legal condition affects only the body of the slave, who, delivered by fate to a master, can not change their status because with the fate not interfere: even the master is the slave of fate.
Especially since the fate - the undisputed mistress of human affairs - can suddenly overturn the present condition and make the slave masters and masters of slaves: " consider that this man, whom you call your slave, was born from the same seed, enjoys the same sky, breathes, lives, dies like you! you can see it for free, as he can see you slave "

Much of the work of Seneca is then devoted to the fleeting nature of time: so they open the letters to Lucilius and De brevitate vitae; the central idea of Seneca is that " do not have a short time, but we lose a lot ".
Life escapes us constantly, but the time we have is enough to make the largest enterprises, in order to achieve the virtue (real goal of human life): how immense riches, if fallen into the hands of an incompetent, are quickly squandered, so a little nest egg, if it happens in the right hands, is invested and increases; so is for life, which is short but can be well exploited. The trouble is that many men are lost in futile activities, thus wasting their time; and it is in this regard that Seneca is a fresco of what he calls the "occupied", and that we might call "idlers", that is those who, immersed in activities totally useless, they do not realize that their life is flowing on. " Life is not short, but that we make it we ", wasting our time in futile activities.

Source: http://www.filosofico.net/seneca.htm