The totality, the whole picture, always must include the observer; and to pretend that it doesn't is a kind of conceit, and maybe even a kind of deceit.
It has occurred to me that 'scientific materialism' is actually a degenerate form of Christianity. From Christianity it has inherited the idea of 'truth', however now materialism understands this as 'scientific truth'. The problem with this is that there really isn't such a thing as 'scientific truth'. There are scientific hypotheses, which are, by their nature, limited and falsifiable. There are enormous amounts of data, far more than any individual can ever hope to know. But the idea of 'Truth with a capital T' is very much inherited from Christian Platonism. It is the remnants of the idea of a realm of truth, a place or a state of mind, where 'all is revealed'. (Think 'the allegory of the Cave'. Perhaps this really was the vision at the beginning of the scientific enterprise.)
Now what it has come to mean is that there only certain kinds of things which we will consider to be real, namely, 'the kinds of things which the natural sciences are able to investigate'. Basically these are things which are amenable to quantification and explanation in third-person terms and are potentially explicable in terms of the laws of physics. Anything whatever which is deemed to 'contradict the laws of physics', is anathematized with all of the passion with which the doctors of the Church used to condemn heresy. An example was John Maddox' (Then editor of Nature) outraged reaction to Rupert Sheldrake's A New Science of Life:
"I was so offended by it, that I said that while it's wrong that books should be burned, in practice, if book burning were allowed, this book would be a candidate (...) I think it's dangerous that people should be allowed by our liberal societies to put that kind of nonsense into currency. It's unnecessary to introduce magic into the explanation from physical and biological phenomenon when in fact there is every likelihood that the continuation of research as it is now practiced will indeed fill all the gaps that Sheldrake draws attention to. You see, Sheldrake's is not a scientific theory. Sheldrake is putting forward magic instead of science, and that can be condemned, in exactly the language that the popes used to condemn Galileo, and for the same reasons: it is heresy".
That is why the so-called 'sceptics' (so-called, because many are actually ideologues rather than actual sceptics) are so vehement in their condemnation of anything they deem metaphysical. Theirs is basically a quasi-religious stance, created around the religion of scientism, which, as I say, has descended from the ruins of Christian idealism. This understands the nature of reality solely in terms of material processes; life as the outcome of chance, in a multiverse which is inherently meaningless and chaotic, to put it in a nutshell.
They conceive of 'the laws of physics' as somehow prohibiting or outlawing anything they regard as psychic or 'spiritual'. In fact, many will also dispute any kind of order whatever, and any notion that the intellect is anything more than the material brain. In this respect, 'scientific laws' now occupy a very similar place to 'God's laws' in medieval society - from which, it must be recalled, modern society has descended. They are, to all intents, proscriptive, rather than simply descriptive, in stipulating what kinds of things ought to be considered.
But if you even have a little imagination, the discoveries of 20th century science did nothing to undermine a kind of pan-religious view of the Universe. The very notion of the 'Big Bang', which seems to say that the universe exploded into existence in the literal blink of an eye, from an infinitesimally small point to the vast expanses of space we see today, is very easy to accommodate within the overall notion of creation ex-nihilo. There is an idea floating around that the universe expands and contracts through endless cycles of Big Bangs, which dovetails very nicely with the 'myth of the eternal return'. In the (disputed) Copenhagen Interpretation of quantum physics, matter is dissolved into 'probability waves' which are intelligible rather than material. Physics is alive with ideas of multiple dimensions and unseen matter. Now matter itself is ultimately mysterious, something understood in terms of waves and potentialities instead of absolute point-particles. There is plenty of space with all of this for a spiritual view of life - arguably more so than there was 100 years ago.