Duality of material and immaterial is itself a debate, so this question begs that question ( as has been noted ). But, whether there be 'duality' of material and immaterial or not, what would seem to be separated by 'duality' and unified otherwise, is essentially the one reality of energy vibrating. Thought and space, emotion and matter, also are energy at a frequency of vibration. This goes deeply into many focuses and controversies - but it is self-evident1 - and yet subtle, and abstract. It can be osbscured.
The way to access and interact with any world, phenomenological or otherwise, is the plane of energy and vibration which integrates and substantiates all else, whether that be perceivable or unmanifest.
There will be a crying out for proof because of my assertion, I know, in times and places where energy and vibration is not a known or common state of being. Strangely, there is frequent use of the word "I" in these same times and places, by the same individuals who cannot find proof of energy and vibration. How the word "I" can be used with such fervency as if the word was defined and proven, is odd. Similarly, it is odd to many who do know the nature of energy and how to hold frequencies, how that reality is questioned, like "I" ought to be questioned, or "God" ought to be, as words legitimately used. The "God" and "I" presuppositions are secondary to a wider presupposition I pinpoint in my footnote.
It is possible to hold a frequency of vibration in a medium - thought or similar, such as by encouraging and sustaining an emotion as actors do - and by that focusing an energy that is itself manifest. It is possible ( and common ) to manifest phenomenological realities and events without "being" material in nature. To manifest is one of many formats of energy of a certain frequency of vibration. Interestingly, only one of the many "channels" or functionary posts of energy vibrations is manifestation. Others include: transformation, unification of many parts into one whole, resolution of disunity among pieces, substantiation and completedness, initiation, choice, etc.
Using the metaphor of actors again, the sustained focus of an energy gives rise to scenes and characters and entire works of art which become known and distributed, with many individuals participating. Such is history and what we call life, events, reality, etc. Through energy vibrations one can absolutely then be perceived in what we call 'material'. Take directors for example, through the actors. The "I" we call "me" is essentially a director and actor, through the medium of a body. But the same director could work through other means, such as the direct way: holding a frequency of energy vibration. Right now, these words in this question are like a slide on a projector, focusing a thought in view of your consciousness, manifesting it there. Agreement with what I assert is secondary. The eyes and light and material plane are also secondary. At first, now as I write, my intent was given as words and those words convey my existence which is in part holding the vibration of energy which sustains my thought, and which my thought sustains in return, synergistically ( totally separate topic, because my assertion is congruent with reality, and therefore it does not take much intention to hold the frequency ).
The willful originator of a causal thought or emotion used as a means of holding a certain frequency of vibration is easily interactive and causal through objects of manifest appearance in matter, without the causal origin being material in form, just as those who additionally wield a body. The sole variable is the focused willfulness of what would also need to be a self-aware and self-conscious participant observer.
1. The self-evident nature of energy being the basis for all, is obscured by a single prevalent presupposition, not unproven. The conscious self is aware they are aware, and hence conscious. However if the awareness of a conscious self becomes preoccupied with another awareness, or their awareness becomes dissipated by an awareness which is not an awareness but a fixation on an error, that self is limited to the view of them self or the world that is allowed by the worse error, not the loudest truth. The truth can be used to remove the error, but the error, left intact, can also dismiss reality for that moment. Honesty is the courage to reverse the reversal of truth, usually, which involves deeply and widely questioning the otherwise obvious. But the fixation I will outline so wide-spread most individuals are not accustomed at all to being in any other frame of reference, or having any other state of being:
There is a wide spread conviction that individual life is primarily physical or entirely physical, and that format of physicality is reality, which is caused and sustained ( it is an energy in vibration, and held to an extreme ) through calendrics. Calendrics is a specific form of chronomics, which is a form of language and communication and a way of understanding others, based on timing rather than symbols or semantics. The medium is the message, and the medium is: object ( "Earth" ) orbits ( "moves through space in an oval shape" ) around object ( "Sun" ). This introduces and sustains two objects and one answer for the meaning of life. An oval shaped journey measured as 365.2524 days and called a year.
Currently there are only physically based calendrics in use in the established world ( in the most sustained and intently entrenched vibration of energy ). This produces physically focused adherents to a certain language of reality, and that language of reality is thus "truth." In other words, physical calendrics is "God" - that is the best definition of the word. Even "money" depends on calendrics. Also, calendrics is the entire underpinning of what is built upon that imposed group self-awareness / mythology, which is civilization / society ( note: not "community" which is not dependent on rule of law, which is dependent on calendrics - "to date" - as that is controlled by certain courts which exist at pre-decided times, in pre-decided places, chosen long ago and not questioned and replaced "to date" ).
With every single voice in an argument agreeing on one thing, there is no real debate on anything else, only squabbling among people fundamentally agreed. Even if there were disagreement enough to cause all to part company ( physically ), there would still not be enough to force them from out of the same core group unless they also severed all other bonds, such as language, financial concepts, law, etc - and calendrics. Even if those of us on this thread share different views, we all share the same need ( not desire ) to adhere to a certain calendric. So though we may all disagree, only some of us might be able to actually know any other reality than the area in dispute. So there is no real way unless someone has a way to provide one, such as what I am doing here, to provide a way for the topic to exit a deadlock and be discussed without one core and all permeating presumption, obscuring all almost entirely. Again, there is not absence of proof or absence of self-evidence of energy vibration, there is inability to see through an obscurity. There are few communities and individuals who have overcome this difficulty, but it has been done. It is unpopular though, because it involves a total reconsideration of everything, including who one is. Especially who one is. Sadly, most prefer not to do that.