Jovain asked:

The knowledge of the truth, does it necessarily entails the dispersion of illusion?

Answer by Jürgen Lawrenz

You cannot speak of truth as something unrelated to human beings. Truth is a concept; it does not exist all by itself. So it is meaningful only in a human context. Accordingly the same applies to illusion. Knowing the difference between them relies on common human experience.

Illusions are generally speaking false interpretations of certain states of affairs. They can also result from defects in perception. Both we know about both only because, on the whole, we make correct interpretations and inferences of the states of affairs that rule of our life. To say, for example, that our senses are fallible, is saying precisely nothing. They are fallible in a limited degree. Instead of drawing the conclusion that ‘therefore’ we can’t trust our senses, we should be astonished how reliable they are. Most illusions are indeed not mistakes by our senses, but of our judgement on the report of the senses. Knowing this throws a different complexion on the matter!

I suspect, however, that your word ‘illusion’ should really be ‘delusion’. Illusion has very little to do with truth–rather with mistakes. Whereas delusion is a more direct counterpart to truth. We humans have been beset by delusions of many kinds throughout human history. Sometimes, after a long period of believing them to be the truth, we decide that they did not conform to the truth, since we found a better truth in the interim.

That’s typical. Our deepest desire is for a meaning of life; and since we cannot find it in the empirical world, we hope to find it in the spiritual world. And so we become vulnerable to what our authority figures claim to be truths that confer meaning on our existence. Most religions fall into this class, which is why there is a constant stream of different faiths and why many end when they are replaced by new ones which offer a more needful or convincing truth. But this does not solve the problem of delusion, because ultimately there is no objective yardstick to either the truth or to delusion.

Accordingly there is no single truth to remove every trace of delusion. We can be cured of many illusions by knowledge of truthful facts; but we cannot be cured of delusions unless we actually wish to abandon them.