Francis Bacon, Of Simulation and Dissimulation:
DISSIMULATION is but a faint kind of policy or wisdom; for it asketh a strong wit and a strong heart to know when to tell truth, and to do it. Therefore it is the weaker sort of politics that are the great dissemblers.
Tacitus saith, Livia sorted well with the arts of her husband and dissimulation of her son; attributing arts or policy to Augustus, and dissimulation to Tiberius. And again, when Mucianus encourageth Vespasian to take arms against Vitellius, he saith, We rise not against the piercing judgment of Augustus, nor the extreme caution or closeness of Tiberius. These properties, of arts or policy and dissimulation or closeness, are indeed habits and faculties several, and to be distinguished. For if a man have that penetration of judgment as he can discern what things are to be laid open, and what to be secreted, and what to be showed at half lights, and to whom and when (which indeed are arts of state and arts of life, as Tacitus well calleth them), to him a habit of dissimulation is a hinderance and a poorness.
But if a man cannot obtain to that judgment, then it is left to him generally to be close, and a dissembler. For where a man cannot choose or vary in particulars, there it is good to take the safest and wariest way in general; like the going softly by one that cannot well see. Certainly the ablest men that ever were have had all an openness and frankness of dealing; and a name of certainty and veracity; but then they were like horses well managed; for they could tell passing well when to stop or turn; and at such times when they thought the case indeed required dissimulation, if then they used it, it came to pass that the former opinion spread abroad of their good faith and clearness of dealing made them almost invisible.