The falsehood does not differ from deceitfulness just because the last is carried out with a precise intention and purposed to harm some persons.
Beside these two aspects, the deceitfulness seems to share some truth, while falsehood is apparently forced by the truth to occupy a limited place as its opposite value.
The deceiver creates the appearance of the truth and wills that those he deceives to behave themselves in a true way.
Though this mechanism of creating appearances was known starting from the first Greek philosophers, its effectiveness has to be refuted each time when it is grounded a philosophical account.
The permanent renewal of such refutation is motivated by the paradoxical nature of the attempt of establishing the truth together with the accounts of reality it gives birth.
Without any contempt for the preceding ‘true’ accounts of reality, all of them may be exposed as means of deceitfulness. For nobody wants to establish a limited truth - as it is as the counterpart of the falsehood -, but rather that truth which can spread out as an image of reality and further as the reality of those who receive it. It is paradoxical because the model of such extension is borrowed from the practice of deceiving.
Therefore, the preparation for truth has to learn from the experience of deceitfulness.