I am a materialist or physicist. This means when it comes to physical objects I am a realist, and when it comes to abstract objects, universals, numbers, properties, functional characters, dead people, etc, I am an anti-realist.

The task of a materialist is how to explain about abstract objects, universals, numbers, properties, fictional characters, dead people, etc, that we most definitely talk and think about.

Yes, I have said the answer already – we talk and think about them.

Fictional characters are perhaps the easiest examples to start with. Simply, we created them out of the imagination of the mind, the brain. If it is that easy to create a fictional character it should not be difficult to create different categories of things. The very term fictional character is in-itself a category. There are no fictional characters, and there is no such thing as the category of fictional character. We created them with our imagination and language.

The entities in our minds are not the same things as the physical objects in the world. They are separate. Sometimes they are specific to the particulars as representations of them as we are sensorarily online. Sometimes we are thinking of them when they are not in our sensory fields. This is enough to make us realise their difference. I can think of something whether it is in my field of my senses or not. Again, they are separate.

From this, I can say the physical objects are not the same as the thought entities, and both are not the same as the symbolic entities (words) which represent them.

Materialists are often at a loss for how to defend their position because they do not define what thoughts and words are. I may call thoughts and words entities, and this may make them sound object-like, but they are not. Thinking is a process of an object. Words are a verbalisation process of an object. Processes do not exist. Processes are properties of objects. Properties do not have instantiation without the objects that instantiate them.

There are objects and properties of objects. Only objects exist. Only particulars exist.