If you look at the philosophy of science, the philosophy of science limits science to only those aspects of reality, that enter our sensory systems from the outside. This "from the outside" philosophy makes it possible for more that one person or team of people to verify what is being perceived by another. Material objects can be felt with the hand, seen with the eyes, smelled, tasted and even knock on, to make a sound, with the properties of human senses similar enough, to verify it is the same object.
Beyond this, there is also a range of objective data that lies outside this philosophy, which materialists cannot fully explore via their extroverted philosophy.
For example, if I had a dream and related the details of that dream, even if I was being 100% objective to what I saw in the dream, nobody else can repeat my exact dream experiment. That specific dream will be called unscientific and subjective even though it was carefully observed and recorded in an objective science way in the first person. The philosophy requires the third person, so others can verify.
Everyone has had a dream to know this type of neural and conscious affect exists, but specific dreams by individuals are very often, unique, thereby falling short of the philosophy of science, since you cannot get a second or third verification.
This is one of the reasons science has no consensus definition for consciousness. We all have the gist of what consciousness is, and through being self aware, one observe it within ourselves and in others. But since this partially needs to be observe from the inside, and not exclusively from the outside via our five senses, science is not sure how to catalog it or define it. It does not fall exactly within the boundaries of the philosophy.
Psychology does deal with this type of phenomena, but psychology is called soft science, since the researcher has to depend on the word of the subject, since they cannot directly see what the patient sees or feels since there is no tool to extends the senses, there.
Spiritualism is not limited by the philosophy of science and materialism. It crosses the line in the sand. Spiritualism, through self observation; prayer, meditation and internal feedback, will attempt to characterize the unique and collective first person data connected to consciousness. The various religions of the world are compilations of this internal and feedback data which comes from deeper places of the human psyche, and how it impacted materialism; fate.
Computers; hardware and software
One way to describe both sides of this philosophical line in the sand, between materialism and spiritualism, is with the computer analogy of hardware and software, respectively. A computer without software is a bunch of hardware with nothing to do. While software without hardware is on the other end of that same boat. Each exist on their own, but each will only come to fruition when they interact with the other. This co-dependence can make one assume they are one in the same, until modern computers came along to show these are two things and two distinct specialties.
An old fashion Cuckoo Clock was able to get a type of animated affect with only hardware; springs and gears timed out by teeth count, to leverage and move. This analogy is still how many materialists view the brain and consciousness; cuckoo clock based on hardware.
This pure hardware approach was even scaled to simulate consciousness via the early automatons. The problems was, these were complex to make and were not very flexible in terms of being more than a one trick analog and mechanical pony.
The idea of separating the tasks into separate software and separate hardware was a breakthrough. You could have one set of hardware. It could be manipulated, in countless ways, simply by changing the software. This reduced costs. The brain is efficient like this. This duality for consceiouebnss and life is connected to the most important duality within life; water and organics.
Water and Organics; software and hardware.
The organics of life are like the hardware side of life. Carbon creates the solid materials of life through primary covalent bonding and polymerizations. This hardware is immersed in the majority component of life, which is water. Water is not fixed like ice, but it is a fluid held together, in bulk, via secondary bonding. Water is like the software side of life being very flexible to the situation.
The solid carbon hardware is immersed in the more fluid water, with their interaction impacting each other. For example, DNA will not do anything by itself in isolation or if it is immersed in any other solvent. It was designed by nature with water in mind, since only water to fluff it out in very specific helical ways to make it bioactive.
The DNA by being a sturdy covalently bonded material has an impact on the local and bulk water that binds to the DNA, and then extends into the fluid continuum. In fact, the water attaches to the DNA in such repeatable ways and specific ways, that water can be used to finger print genes and even base pairs.
Three states of matter; gas, liquid and solid.
If you compare the three most common states of matter; gas, liquid and sold, each has distinct characteristics with liquid the most anomalous. For example, gases can be placed under pressure but not under tension. Gases are measured by their partial pressure. As we reduce pressure, gases still wish to break away from other gas molecules, and never really see tension. Even under a vacuum they bounce off the walls to create a pressure.
Solid can be placed under pressure or tension but not both at the same time and reach a steady state. We can push and pull a heavy wagon, so it sees both tension; pull and pressure; push, but it cannot reach steady state since it will keep moving. If we both just pull or both just push from opposite sides, the two forces will cancel and it will stop and be at steady state. But if we do both, it will move or rotate.
Liquids are interesting in that they can exhibit both tension and pressure at the same time and be at steady state. The easiest example to see is a glass of water at atmospheric pressure. It has pressure from the atmosphere, and surface tension with the air.
With life being a combination of solid and fluid, that is closely interacting, the fluid state becomes a wild card where another type of pseudo-state can appear within solids that is not characteristic of pure solids. This is my favorite subject, but it gets technical to make it all come together. It brings us back to software and spiritualism. Baptism in fluid water is key conscious transcendence.