The ancients knew that the forms of matter could be categorized in certain ways before the rise of the scientific method. All cultures had a basic and fundamental grasp on the states of matter via earth, water, air, and fire. Which is comparable to the fundamental concept of solid, liquid, gas and plasma. But this is Western notion.
In the East they also thought of matter being composed of earth, water, fire but ignored air and included metal and wood. Why did they not include air? Didn't they notice bubbles in water or smoke? Who knows, but the inclusion of metal and wood may seem odd. But like the four simple states of matter it shows a primitive grasp of science.
The Chinese-Eastern inclusion of metal and wood as primary elements in the ancient way shows that they could sense that matter could be divided in to metals and non-metals. When you look at the periodic table of elements you see that 'modern scientific' elements generally come in two 'genders' - metal and non-metal. Wood is essentially composed of non-metal elements! Carbon, Oxygen, Nitrogen, Phosphorus, and Sulfur!
Basically a few Ancient Chinese thinkers recognized that 'matter' is composed of metallic material and wooden (organic) type material. The modern elements on the upper right hand of the table are the most abundant elements for life and wood - Carbon, Oxygen, Nitrogen, Phosphorus, and Sulfur.
The great coincidence is that the nation that is the best mix of East and West - Russia - first came up with the periodic table of elements, thank you Mr. Mendeleev.