Democritus, known as the “Laughing Philosopher” for his emphasis on cheerfulness, lived from around 460 BCE to 370 BCE. Hailing from Abdera in Thrace, he was a pre-Socratic Greek philosopher and a central figure in the development of atomic theory. Democritus proposed that everything in the universe is composed of tiny, indivisible particles called atoms, moving through the void. His materialist philosophy challenged the prevailing views of his time, offering a mechanistic explanation of the natural world. Despite his significant contributions, much of his work survives only through the writings of later philosophers, yet his ideas laid the groundwork for modern science.