Javier asked:

What is materialism?

and Artemio asked:

I know that in materalism people believe only in things made of matter, but I would like to have a
more complex definition.

============

The only things that exist for a materialist are described by physics. Entities which fall under the
science of physics are atomic structures, time, space and forces. At our level of perception we take
objects such as tables and chairs as uncontroversial existents. These are macroscopic objects to the
physicist, since what he sees are bundles of atomic structures. The materialist can admit that tables
do really exist as matter, since the atomic particles are responsible for the nature of the table.
Otherwise put, the table is determined by physical particles and exists because these fall under the
laws of physics.

So there is something which is a table, but the problem is that what determines our concept is not the
microscopic properties of physics, but the way the table looks to us, as a large, brown, wooden thing.
As long as the table appears like this, its microscopic structure could be quite lawless. Further,
although micro-physical structures might determine the fact that the table is large and wooden, the
descriptions "large" and "wooden" do not belong to the language of the laws of physics. For these
reasons, the materialist has to hold that it is not the appearance which determines our concept of a
table, but properties which fall under the laws of physics. What causes us to perceive the table is its
micro-structural properties.

This has consequences for mental states and concepts. The way in which the object looks to us is
phenomenological. Seeing is a subjective sensational state, and this cannot exist because it does not
fall under the laws of physics. What can exist is a physical brain state. This means that what enables
us to perceive the table, and hence form the concept of the table, is a relational state between the
brain and an external physicist's description of the object. This means that we should be able to
perceive objects by sight without any phenomenology.

It is uncontroversial that a perception is a relation between the brain and the world of matter, but if
appearances don't exist then we don't learn about physical objects from the way they look to us as
everyday perceivers. Furthermore, lots of our concepts are not of physical things: God, the soul,
ghosts, fictional characters, beauty, good and evil. Given that these are unreal, values or based upon
faith it might seem reasonable for the materialist to say that there is obviously no relational state
between the brain and the world in these cases because these things don't actually exist as material.
However, a person needs to acquire the capacity to be in a brain state in which he thinks about God
or beauty, and if it is from the world it is from the world of other people, of sound, words and
meanings. This is to return to the initial problem — words and meanings do not fall under the science
of physics.

Rachel Browne