Parbouj has been making the complaint that Lewis, and those like myself who make use of his philosophical ideas, conflate atheism with materialism.
The interesting thing about that is that when Lewis himself became persuaded by anti-materialist arguments, he didn't become a theist, he attempted to avoid traditional theism by adopting an alternative philosophy that was very prevalent in his own time, namely, Absolute Idealism.
Here's what he wrote about it:
It is astonishing (at this time of day) that I could regard this position as something quite distinct from Theism. I suspect there was some willful blindness. But there were in those days all sorts of blankets, insulators, and insurances which enabled one to get all the conveniences of Theism, without believing in God. The English Hegelians, writers like T. H. Green, Bradley, and Bosanquet (then mighty names), dealt in precisely such wares. The Absolute Mind—better still, the Absolute—was impersonal, or it knew itself (but not us?) and it was so absolute that it wasn’t really much more like a mind than anyone else….We could talk religiously about the Absolute; but there was no danger of Its doing anything about us…There was nothing to fear, better still, nothing to obey.
Lewis never supposes that anti-materialist arguments (such as the argument from reason) establish theism immediately and directly. Nor do I. I do think the my argument does establish that what is basic to reality is something mental, and that it is cannot be fully described in non-mental terms. I also think that that mental something at the base of things, is most coherently drawn out in terms of a theistic philosophy.
I have always been very explicit about this, see, for example, here.