Materialism vs Idealism

First, let's do away with the connotative misconception attached to the term "materialism"; 

MATERIALISM DOES NOT MEAN LOVE FOR MATERIAL THINGS.

Philosophically, materialism is a viewpoint that negates "idealism" and claims that material precedes ideas. 

Here are two arguments in favour of materialism.

1. Brain is a matter and ideas come out of the brain.

2. Language consists of signifiers/words linked to the signified/image; If the signifier "tree" is mentioned then suddenly the associated signified/image of the tree appears in mind. But if an unknown signifier is mentioned then no image can be traced in the mind. That's how every image/imagination comes from material experience/observation. 

Then how do scientists and artists invent? 

S.T Coleridge defines it as "secondary imagination" which works by collecting components from "primary imagination" and combining them to form new things. For example; imagining a donkey with a dog's head is achievable- which is considered "secondary imagination"- since both animals are available in "primary imagination". So, imagining a human flying is possible in "secondary imagination" because the concept of flying extracted from observation of birds and observation of humans are both available in "primary imagination". 

So, the root of all ideas can always be traced back to the material origin.