Final answer:
In materialism, 'material' encompasses both matter and energy, with the understanding that everything in existence is made up of energy in some form. Materialists deny the existence of non-material entities since they cannot be empirically verified, and our material knowledge comes from physical observations and scientific research.
Step-by-step explanation:
Materialists understand 'material' to refer to matter, energy, or any entity that consists of energy. According to materialism, all things that exist in the universe do so in a material form, meaning that they can be empirically detected or interacted with through the physical world. This encompasses everything from atoms to molecules to the forces that govern their interactions. The absence of any non-physical or non-material existents is a core aspect of materialistic thought.
Materialism, as a form of Monism, asserts that there is only one kind of substance in the universe: material substance. All phenomena, including those that might be described as mental or spiritual by other philosophical schools, are ultimately founded upon material interactions. This viewpoint has significant implications for the discussion on the existence of entities such as gods, souls, and angels because it denies their existence if they cannot be empirically verified.
The evidence for the existence of material substances is physical observation and experimentation. Our scientific understanding of the universe is built upon the study of matter and energy, interpreted through the use of mathematics, physical measurements, and technological advances that extend the capabilities of our senses.