As we uncover the workings of the natural world certain things become clear:-
1) Stuff (matter-energy-space-time) interact with each other in highly predictable ways which we call "laws of nature", "causality" etc. However the reason for the existence of this structured patterns of behavior and their invariable attachment with stuff is unknown.
2) The laws of nature themselves are mathematical, a realm of abstract and extraordinarily rich realm of reality that is "somehow" glued into "stuff" through these laws and accessible to knowledge through rationality. Why should there be such a realm of abstract rational world of mathematics and why they intermingle with stuff is also not known.
3) Stuff..connected with the mathematical world via the laws of nature, is extraordinarily and unexpectedly fecund, coalescing in property rich groups with utterly novel qualities and functions starting from molecules, crystals, living things, stars, galaxies and sentient beings. The repeated (and apparently limitless) potential of emerging wholes with novel properties all stacked on top of each other (from molecules to man i.e.) from "stuff" is observable and describable; but why stuff has such properties is unknown.
Therefore Hindu-s propose that there is something more fundamental than matter-energy, laws of nature, mathematics and consciousness/information. On this more fundamental entity all these domains rest, and of which these various domains are aspects of. And this singular fundamental entity, which we call Brahman, provides the connecting glue and the structural richness around which stuff is coalescing to make it manifest in the sensory plane. This provides a "why" explanation rather than a what and how explanation. Such an explanation is needed as the interconnectivity of stuff, laws, maths, information, consciousness and repeated emergence are not mere facts, but extraordinary features that cannot be left unexplained.
And just like biology has provided us with senses to see stuff and rationality to see mathematics..it has also provided us with inner capabilities, which when honed through meditation or other proper spiritual practices, can help us grasp this fundamental entity undergirding all these domains of knowledge...at least to some extent.
That is the argument that I would ask atheists and materialists to consider.