Apparently, the best way to avoid illusions is just to "stick to the truth", which, incidentally, is what most people say they do. Both skeptics and religious fanatics claim to have found a truth, the truth, and yet... they disagree... how can we be sure which one is right, or if there is anyone who is right in ascertain that he has found the truth?
I must confess that I am terribly romantic and that my main constant passion in life has been for the truth. I have pursued it in religions, science, philosophy, mysticism, etc. I must say I have never found convincing reasons to take anything as an established truth.
Religion relies too much on inner feelings and intuitions of which we do not understand the origin or validity, no matter how comforting and enlightening they may be.
Science is always overcoming itself, restructuring the very foundations just to achieve small differences in its predictions (at least initially, like in the Copernican revolution, and then in Einsteins theory of gravity). So how can we trust our present theories? In the billions of years in which a scientific civilization may evolve will not many other paradigms be found, that will completely reshape our vision of things? I find it highly improbable that even a mere million years of evolution will not bring an almost completely different vision of our universe.
Mysticism was a mystery when I started to venture in its core, but I came to believe that its essence has nothing to do with truth or falsity, even less like something that can be put into a theory. In my view Mysticism's value to the world is in making people free, it is in the discovery and cultivation of freedom of each one's core freedom that its value resides. Mysticism taken as a (set of) theory(ies) is as unwarranted and dangerous as religion.
Philosophers disagree in almost everything, so both skeptics and constructive thinkers, taken together with the fact that no one has presented a valid argument to demonstrate even the most basic truths (like the falsity of solipsism, or that the world we see is not a simulation, that mathematical truths are real, that the sun will rise tomorrow, etc) is itself the best proof that the truth, if it was ever found, could not be proven.
Mathematics and other abstract sciences have an equivocal relation with reality and, although they appear obvious at first, they loose all that evidence after generations have advanced in their comprehension. For instance, at first it seems more than obvious that two straight parallel lines could never touch. Well, it seems they can, in geometries with more than three dimensions, and, more to the point, we seem to live in such a world. When irrational and imaginary numbers were presented for the first time they were badly received, like an anomaly. And yet they seem pervading and unavoidable in our mathematical depiction of nature. Besides no mathematician can demonstrate that the world is more than a dream or a simulation. Perhaps all the mathematical and logical truths we see are nothing more than illusions, falsities, imprinted by those who control the dream or simulation.
So, as you see, althgouh I am a true lover for truth, still in love, passionate love even, I can't say I possess it. I search for it, I desire it, I want to have it. But I must recognize that I was never able to grasp it fully, to possess it, to know it inside out. Instead, like a lover who likes to keep the light of passion alive, she keeps showing me little bits, here and there, that may or may not be, her true self. And, in the end, I am where I started in terms of possession, although I gather, in all these games, a lot of imaginary images of how it true self might be. Perhaps she is a machine, like a robot, using feelings as fuel, or perhaps she is really just love using images of machines to keep the game of love going, or perhaps it is something not so interesting from a human perspective, like a universal law, and the universe is as indifferent to our adventures as we are to the tempests in Jupiter.
In sum: we don't know, we live in a sea of mysteries.
I came to agree mostly with a recent philosopher named Karl Popper who says that all we have are hypothesis, that encompass conceptual theories but also behaviors, for any expectation (for instance we are able stand up by having what can be interpreted as a very big number of expectations or hypothesis regarding the way the body is affected by gravity, all these hypothesis are constantly being reformulated - for instance, if we learn how to dance, ride a bike, jump on the trampoline, etc).