How did Henri Bergson distinguish duration from clock-measured time?

Henri Bergson distinguished between duration and clock-measured time by arguing that scientific time is a spatialized, quantitative construct that fails to capture the true nature of lived experience.1

In his work Time and Free Will, Bergson posited that:

• Scientific Time: This is the time employed in physics and mechanics. It is essentially a mathematical abstraction that treats time as a series of discrete, measurable units. Bergson argued that this approach "eliminates duration" by spatializing time, effectively confusing succession with simultaneity and quality with quantity.1
• Duration (Lived Time): This represents the immediate, internal awareness of the self. Unlike the clock, which divides time into uniform, external segments, duration is a continuous, qualitative flow. Bergson maintained that psychological states are unique and cannot be quantified or numbered without falsifying their nature.1

By clearing away the confusion between these two concepts, Bergson sought to demonstrate that arguments against human liberty based on scientific determinism are fundamentally baseless.1