Émile Durkheim, a foundational figure in sociology, profoundly argued that society is not merely an aggregation of individuals or the sum of their individual acts, but rather a distinct entity with its own reality. This core idea is central to his concept of 'social facts' and his emphasis on the sui generis (of its own kind) nature of society.

Durkheim contended that if society were simply the sum of individual acts, then sociology would be reducible to psychology. However, he observed that social phenomena exhibit characteristics that cannot be explained by individual psychology alone. He introduced the concept of social facts, which he defined as 'ways of acting, thinking, and feeling, external to the individual, and endowed with a power of coercion by virtue of which they exert control over him.'

Key aspects of this argument include:

1. Externality: Social facts exist outside of individual consciousness. For example, laws, moral codes, religious beliefs, and customs are pre-existing structures that individuals are born into and that shape their behavior, rather than being created by each individual.
2. Coercion: Social facts exert a coercive power over individuals, compelling them to conform to societal norms and expectations. This coercion can be formal (e.g., legal sanctions) or informal (e.g., social disapproval, peer pressure). Individuals who deviate often face consequences, demonstrating society's power over them.
3. Collective Consciousness: Durkheim posited the existence of a 'collective consciousness' – the shared beliefs, ideas, and moral attitudes that operate as a unifying force within society. This collective consciousness is more than the sum of individual consciousnesses; it is a distinct social reality that binds individuals together and provides a framework for their actions.
4. Emergent Properties: Society possesses emergent properties, meaning that new qualities and characteristics arise from the interaction of individuals that are not present in the individuals themselves. Just as water has properties (wetness, fluidity) not found in hydrogen or oxygen atoms, society has properties (e.g., social solidarity, institutions) not found in isolated individuals.
5. Social Institutions: Institutions like the family, education system, religion, and economy are social facts that pre-exist individuals and shape their lives. They are collective representations and practices that guide behavior and maintain social order.

For Durkheim, understanding society requires studying these social facts and collective phenomena, not just individual psychology. His work on suicide, for instance, demonstrated how a deeply personal act could be explained by variations in social integration and regulation, proving that social forces profoundly influence individual behavior. Thus, society is a complex system with its own structure, functions, and dynamics, irreducible to its individual components.