JWs believe in God and a spiritual realm. In that sense they are not materialists for sure. We won't disagree about that. However compared with other religions they are very naturalistic and rationalistic in outlook. This expresses itself in many of their beliefs and practices. For example:
1. Their basic denial of the concept of a soul as most religious people envisage it. Body and soul are practically synonymous except in a metaphorical sense of "future life prospect". They are effectively monists.
2. Their belief that physical resurrection involves the reassembly of atoms in a particular configuration to recreate the person or soul. You don't get more reductionist or materialist than that.
3. Their rejection of an omnipresent God. Although JWs talk about God as "spirit" they also talk about him as in some sense having a "location" in the heavens betraying a basic materialist bedrock. At one time they even located God in a particular star system.
4. Their rejection of modern day miracles and divine revelation. They claim that the GB is in some sense guided by God, but through reading texts and discussion, not by receiving actual revelation. They also discourage the idea that God would communicate directly with ordinary believers in any mystical sense. Instead they focus on the study of texts and rational belief and practice.
5. Their rejection of mysticism in their religious practice. Their meetings have been likened to business meetings more than religious gatherings. It's a religion with most of the "religion" sucked out of it, so what you're left with is an attempt at belief in the supernatural expressed and practiced in as rationalistic and materialistic terms as possible.
Anthropologist Andrew Holden has written about how JW beliefs and practices are in many ways an expression of modern rationalistic thought rather than in opposition to it.
http://www.lancaster.ac.uk/fass/resources/sociology-online-papers/papers/holden-peering-through-the-watch-tower.pdf
If there is one feature of the Kingdom Hall that occupied my thoughts in the initial stages of
my fieldwork, it would have to have been the absence of mysticism... Their failure to spend much time in meditation, prayer, healing, and
other such rituals demonstrates their unwillingness to recognise that God will intervene in
human affairs. I could not help being struck by the stark contrast between the awesome
symbols of a church with which I was familiar and the rationalism of the Watch Tower
movement.
Rationalism is an essential characteristic of the modern world that stems from the
Enlightenment tradition. It involves a qualitatively new way of thinking concerned with innate
ideas independent of experience.[viii] Weber (1970) regarded the rise of science and
technology in industrial capitalist societies as evidence of a whole process of rationalisation.
He argued that this would manifest itself in the economic distribution of goods and services, in
the ordering of work and in social life in general. Weber also suggested that rationalism would
lead to tension with traditional cultures in which ordinary people for whom religion had been
an important influence would not easily adapt to laws and procedures that were devoid of
human emotion. Communities that operate on rational precepts cannot easily accommodate
charisma or individual creativity. Rational systems are generally purposeful and pragmatic,
eschewing all arbitrary performances and events. Religious beliefs are, however, based on
faith; and since this is something that cannot be quantified, a certain amount of tension
between these two phenomena is inevitable.
The Witnesses pose a challenge to traditional religion, not least because they undermine the
beliefs and rituals of established churches.[ix] Their rational system of beliefs equips them
with strategies for recruitment and enables them to prove beyond all doubt that their theology
is the word of God. The contrast between this and mystical religion manifests itself in visual
imagery and styles of worship. Biblical texts are consulted not only for the substantiation of
doctrines but as a blueprint for everyday conduct. Scriptural literalism is a rational means by
which the world and its problems can be explained. The Witnesses believe that Jehovah
created the world in seven days and intended Adam and Eve to live in a state of eternal
happiness. However, it is as though they believe that since the fall, he has gone into semi-
retirement until such time that humankind reaches the point of its own destruction. This is
perhaps one of the reasons they spend little time in prayer. Glossolalia, creed recitation, even periods of silent meditation are so far removed from the Witnesses’ activities that someone
claiming to have had an experience of a transcendental nature are unlikely to find solace in a
Kingdom Hall. At no point in meetings is time devoted to individual prayer. Spontaneous
prayer and prayer by invitation are also absent. Unlike the Roman Catholic tradition in which
relics, crucifixes, statues, pictures, holy water and tabernacles are an indispensable part of
the spiritual ethos, these places of worship are sparse and disenchanted. Although they are
always clean, tastefully decorated and well maintained, Kingdom Halls are essentially
functional places.[x] The spatial layout of formally arranged chairs and an elevated platform
on which devotees delivered their well-rehearsed sermons exemplify the Witnesses’ rational
style of worship. Elders in the background who quietly confirm the order and content of the
meeting from their official itineraries enhance the atmosphere of order and precision.
The Watch Tower movement does not only eschew mysticism, it openly condemns it. Its
magazines repeatedly warn devotees of the dangers of apostasy by showing pictures of
Catholics praying before images of saints (particularly the Virgin Mary) for intercession. Elders
propound the view that venerating anything or anybody other than Jehovah constitutes false
worship and is forbidden in scripture.[xi] This idea is nothing new (it was, after all, one of the
arguments that came out of the Protestant Reformation), but what is significant is that the
Witnesses’ style of worship resonates with the idea that religious superstition is contrary to
modernity. In his work on the Enlightenment in The Crooked Timber of Humanity, Isaiah
Berlin writes:
The rational reorganisation of society would put an end to spiritual and intellectual
confusion, the reign of prejudice and superstition, blind obedience to unexamined
dogmas, and the stupidities and cruelties of the oppressive regimes which such
intellectual darkness bred and promoted. All that was wanted was the identification of
the principal human needs and discovery of the means of satisfying them. (Berlin
1990:5)
Berlin is suggesting here that rationalisation would bring about the death of superstition and
the rise of human emancipation. Few people would regard the Watch Tower movement as
liberating in any sense of the word, yet the Witnesses’ unabated attack on saint-cults and
their refusal to accept the “unexamined dogmas” to which Berlin refers could be seen as
freedom from what many regard as the oppressive forces of traditional religion. Though they
are religious in the sense that they believe in the supernatural and offer their allegiance to a
deity, the Witnesses’ one true interpretation of scripture eradicates superstition, drawing
instead on the principles of modern reason. This suggests that the ‘knowledge’ required for
membership of the Watch Tower community is fundamentally different from the emotional
intensity often associated with, for example, evangelical Christianity.[xii] Reading textual
material is more intellectually demanding and time-consuming than making a sudden decision
to offer one’s life to God at a charismatic revival meeting. This is not to suggest that the
Witnesses do not believe what they ‘know’, or that evangelical Christian ministers are always
sure that those who step forward to be saved have genuine conviction, but rather that
preparation for Watch Tower ministry is devoid of supernatural invocation.[xiii] One indicator
of this is the fact that the familiar stories in which born-again Christians declare how lost they
were before they saw the light are absent in the testimonies of Witness converts. The
Witnesses’ failure to acknowledge grace or even their own unworthiness reflects their belief
that salvation can be earned by taking the time to read about God and adhere to the way of
life prescribed by the Governing Body of his earthly Society...
Until recently, sociological literature has tended to propound the view that world-renouncing
sectarian religion cannot survive the onslaught of modernity which is, among other things,
rational, secular and materialistic. But these theories offer scant empirical analysis of
millenarian movements. The rise of the modern state, modern capitalism and modern science
have no doubt been the cause of great tension between faith and reason, but they can in no
way be shown to have brought about the death of God. The Watch Tower Bible and Tract
Society is an example of a movement that has managed to maintain a piety that is as ascetic
and puritanical as any version of orthodox Christianity. At the same time, it is a religion of
disenchantment that involves the systematic study of textual material. This requires skills of
literacy, reason and learning by rote. The Witnesses’ style of worship, their meticulous
collation of statistical data and their ministerial methodology reveal an indubitable
dependency on modern rational principles. In an age in which social movements articulate
expressive and aesthetic identities, the Watch Tower Society stands out as rational,
calculating and conservative. Its style of worship and ministerial procedures reflect a
community that operates on the basis of what Weber called ‘technical reason’. Weber argued
that in the post-industrial period, Western societies had become governed by rules and
regulations deriving from legal-rational authority (Weber 1922).[xx] While some devotees find
the movement’s demand for loyalty difficult to satisfy, however, it would be a mistake to
suggest that they find its appeal for service oppressive. Its rational-authoritarian nature
produces both the conformity and the strong feeling of unity that enable it to function.
Watch Tower evangelism succeeds because of the technological and cultural resources that
are available in the twenty-first century. The Witnesses’ recruitment methodology requires the
use of modern communication techniques as well as sophisticated technology such as multi-
media software. The movement operates an international business enterprise for the
production and dissemination of tracts and magazines and the expansion of its membership.
Photographs of gigantic office blocks representing its headquarters and printing works appear
in glossy reading materials. These photographs do not, in any sense, depict an organisation
that is anti-modern or anti-materialistic, but rather one that prides itself on its modern rational
image. This is, to all intents and purposes, a global, multicultural corporation. The modern
world the Witnesses ostensibly oppose is the world they also mimic. Notwithstanding the
tension between faith on the one hand and reason on the other, the Witnesses are
remarkably successful in utilising rational means for their equally rational ends.