Are there higher dimensions and higher states of consciousness?
In the manifestation, yes there is always something higher or lower; that is the very nature of duality. The mind never stops measuring, expanding and creating. The universe seems to have infinite possibilities of experience still unfathomable to us and open for exploration. Metaphysics is a natural extension of our minds and thus is interesting and exciting. I find it fascinating.
Spiritual Realization however is a different pursuit altogether. It has nothing to do with explorations in duality, except for exploring the psyche and detecting the cause of suffering.
Spiritual Realization is not the expansion of the mind; it is recognizing our Being from where the mind may be simply witnessed without any compulsion for having any particular experience or any particular knowledge or being in any particular dimension.
Spirituality, or the pursuit of Spiritual Realization is, in my dictionary, the pursuit of Spirit, the Essence of our Being, and the tranquility that naturally comes with its realization. And the Essence of our Being does not come and go or is hidden in a higher dimension. It is Timelessness therefore changeless and even present.
The study of dimensions is the study of functions and is perfectly fine; but it is not an obligatory path to Self-knowledge.