We can know how other people think, despite that they are habitually dishonest and live-behind an edifice of lies, because we can observe their us of what some people have called 'projection'. In other words, people accuse others of behaving in the way they themselves behave.
Projection is a misleading term (false causality) if you understand the psychoanalytic reasoning behind it; but the actuality is straightforward enough: By and large, we understand other people's thinking in terms of how we ourselves think.
We could call this 'the law of projection'.
But there is an extra spin on this generalisation - which is made very clear in Tolkien's Lord of the Rings: The law of projection applies primarily to evil.
In other words, insofar as a person (or institution) is evil - that is to say, is strategically working for the destruction of Good - their understanding is constrained by projection.
In other words, the evil can only imagine others as being as evil as themselves. In other words, we can recognise evil by the way of thinking, by the fact that their world view is constrained by imputing evil intentions to others.
The evil cannot even imagine that others may be different from themselves, may not be evil.
Thus Sauron assumes that everybody will want to seize and use The Ring and never even considers that they would try to destroy it; Saruman assumes that Gandalf is also plotting to rule The West and keep the One Ring for himself - and so on.
In sum - evil cannot imagine Good - and cannot understand the rationale of Good: cannot predict the actions of the Good.
But, by contrast, Good can imagine evil - Gandalf, Elrond, Galadriel, Aragorn are all able to understand and predict the behaviour of Sauron. But why?
It cannot be merely that any Good person also contains evil aspects (and uses these to understand evil) - because the reverse also applies: any evil person also contains Good aspects, indeed often a great deal of Good and yet the evil are blinded to Good in others...
My guess is that although everyone is a mixture of Good and evil; the evil are blinded to Good, while the Good are not blind to evil. It is not the special virtues of the Good which make them wiser; it is the malformation of thought which is induced by evil intent.
In sum; we can recognise evil firstly by its projection of evil onto others, and secondly (and more important) by the fact that it evil is constrained by this projection: evil cannot imagine Good in its enemies.
But, my point is that lies, no matter how comprehensive, do not obscure evil - we can see past the lies.