According to S. Radhakrishnan, in India philosophy stood on its own legs, and all other studies looked to it for inspiration and support. (So do I). It is the master science guiding other sciences, without which they tend to become empty and foolish (meme-sciences, based on cross-referencing without validation or even understanding). They call it Brahmavidia - the science of eternal, the science of what is.
On the other hand, Maya is a delusion, which a mind creates out of wrong concepts and categories, made out of mere words. "Verbal-mind" cannot "see" anything for which there is no word. Most of words (as labels) are inexact, subjective, ambiguous. Most of common sense (socially constructed concepts and stereotypes) are mere flawed "mental shortcuts". Maya is much more rational concept that "devil". It is just ignorance.
The philosophic attempt to determine the nature of reality may start either with the thinking self (the nature of mind) or the objects of thought. Where the vision is turned outward, the rush of fleeting events (and impermanent things) engages the mind. To really understand objects of thought know the nature of the mind first (know how the mind itself works and why it is so).
In India 'Atmanam viddhi' - 'know thyself' (nothing but conditioning, hard-wired heuristics and longterm memory) sums up the law and the prophets. Within a man is the "spirit" (I would say "energy") that is the center of everything (what illuminates everything and sees everything in its own "light"). Philosophy and Psychology are the basal sciences of ancient India. Begore understanding of what lies outside, understand what lies within.
Indian Psychology realized the value of concentration (non-distracted, intense awareness) and looked upon it as the means for the perception of truth (reality). It is believed that there are no ranges of life or mind which could not be reached (illuminated) by a methodical training of will (self-discipline of remaining in balance or Yoga) and extracting of knowledge. To apply this intence awareness to the mind itself is the only way to understand its nature.
Traditionaly, the activities of the self (mind) are assigned to the three states of waking, dreaming and dreamless sleep. In dream states an actual "real" world is presented to us (created by activities of our brain). We do not call that world real, since on awakening we find that the dream world does not fit in with the waking world, but relatively to the dream state the dream world is "real" (absolutely convincing). This implies that we could, at least to some extent, create illusory worlds good-enough to convince ourselves that they are real (we are doing this all the time, protecting and maintaining our own models and views). Even waking reality is a relative one. There are no absolute knowledge of truth as subsisting by itself, that tells us that dream states are less real than the waking ones. It has no permanent existence, being only a correlate of the waking state). It disappears in dream and sleep. (This needs some clarification. There is no question wheather or not the "physical reality" exist. It does not disappear. What diappears is our perceptual world - a model which the mind creates and maintains. These statements are declaring that our perception of reality inevitably differs from reality itself and these perceptions and our interpretations of them are impermanent and relative. This is the very core of Psychology). The waking consciousness and the world disclosed to it are related to each other, depended on each other as the dream consciousness and the dream-world are. They are not absolutely real (these are at least 3000 years old observations from Upanishads). In dreamless sleep we have cessation of the empirical consciousness (of the subject, which implies that the "subject" is impermanent and could be created and destroyed on demand, actually - within each thought). Subjectless (and objectless) consciousness is what remains, so it is our true nature (not the products of it). The subject/object false dichotomy is the product of that primordial consciousness/awareness (conditioned by perceptions and language).
What varies not, nor changes in the midst of things that wary and change is, indeed, different from them (like all the reflections are different from the mirror which reflects them). The Self which persists unchanged and is one thoroughout all the changes is different from them all. The conditions change, not the Self. "In all the endless months, years, small and great cycles, past and to come, this self-illuminous consciousness alone neither rises nor sets" (this is about self-illuminating primordial awareness - Atman - the source of impermanent consciousness and related "myself" or "I").
This illusory "myself", like consciousness which maintains it, is impermanent and could be switched on and off. It is the same kind of phenomena like a movie - it is a product of a film, light, projector and the mind of a spectactor, a feedback loop. (The modern view would be that with each thought you have a new version of "myself", the running total of all your perceptions, mental and physical actions - of your conditioning, which people prefer to call "personal experience". This running total of all conditioning is your "I", and there is no "myself" aside from this conditioning).
The principal categories of the world of experience, time, space and cause are self-contradictory. They have no real existence (independent from an observer, from a reference point, a zero on the scale. There is usually no "single cause" for any phenomena. It is a sum-total of many forces, most of which we are unaware of). Yet they are not completely non-existent (they are products of the mind, conditioned by perception, and language, which is conditioned by perception and culture - yes, a mutual recursion here, to use them). These are side-effects, by-products of a human language - useful mental concepts.
The absolute (Brahman) can never become the object of knowledge, for what is known is finite and relative. Out limited mind cannot go beyond the bounds of time, space and cause, nor can we explain these, since every attempt to explain assumes them. Our relative (personal) experience is a waking dream (a mutually-recursive processes between verbal and non-verbal centers and perception. The concepts of the mind interfere with and distort the perceptual input, which in turn, over-writes inner representation of conditioned concepts). Science and logic are parts of it, and products of it too (it is not all what is). This failure of reason is not to be blamed or regretted, but to be understood and realized.
The immutable (E=mc2) seems to be spread out in a moving way (like a flag on the wind). Rays stream out from the Sun which nevertheless does not contain them (not bad for 1000 BC).
The "self" of a man ever struggle to fill up what it think it is lacking, to preserve its "individuality", in order not see its inner void, due to the Maya constituted by the imaginable interval between what they think they are and what they think they ought to be. If we get rid of Maya, suppress the tendency to duality, abolish the interval, fill up the deficit, and allow the disturbance to relax, space, time and causation reach back into the "pure being" (Atman). As long as the original insufficiency of Maya prevails (dissatisfaction of the ego) things are condemned to be existent in space-time cause world (untill the mind will stop re-creating the dream, to wake up from a recursive nightmare).
Maya is not a human construction. It is prior to our intellect and independent of it (like a mirror is independent from all the reflections). It is verily the generator of intellects and concepts. The world of becoming (verbal day-dreaming) is the interruption of being. Maya is the reflection of reality. Yet the world of Maya cannot exist apart from Atman (the source of consciousness) just like after death there is no waking or dream or dreamless sleep. Just a "material world". Illusory representation of its fragment temporal state ceased to exist (this is a good one). As becoming is a lapse from being so is avidia or ignorance a fall from vidia or "just-being" (basically, it says that all the "knowledge" is ignorance to some extent, being only an incomplete, rough approximation to the Absolute. This does not imply that all the flawed models are useless). To know (realize) the "truth", to appreciate reality (as it is) we have to get rid of avidia and its intellectual moulds (naive categories, over-simplified models, social constructs) which all crack the moment we try to force reality into them.
Indian Philosophy tells us that, so long as we are bound by [conditioned] intellect and are lost in the world of many (words), we shall seek in vain to get back to the simplicity (and unity) of the One (String theory, huh?). Philosophy, as logic has here the function of exposing the inadequacy of all intellectual categories, pointing out how the phenomena of the world are relative to the mind that thinks them, and has no independent existence (in the way we think we know them. Map is not the territory). This is, by the way, the fallacy of Object Oriented Programming - not everything in the world is an object. Like not everything in the Universe has a noun or a verb associated with it. But a some tiny subset do.
Enough of ancient Indian Philosophy for a modern sadhu. It doesn't say that intellectual knowledge is useless. They only prove that it will always be incomplete.