How did sensationalism reduce mental life to sensations?

Sensationalism, a radical form of Empiricism, reduces mental life to sensations by asserting that all human faculties and knowledge originate exclusively from sense perception, rejecting any independent originative power of the mind.12

This reductionist approach was most systematically developed by Étienne Bonnot de Condillac, who argued that all mental operations—such as attention, memory, and comparison—are merely transformed sensations. In this view:12
* Attention is simply the occupancy of the mind by a sensation.1
* Memory is the retention of a sensation.1
* Comparison is a form of twofold attention.1

While John Locke initially distinguished between ideas of sensation and ideas of reflection, sensationalists minimized the latter, viewing the mind as a passive recipient of sensory data. By treating complex conceptual entities as nothing more than the compounding of simple sensory materials, sensationalism effectively eliminates the need for innate ideas or independent mental faculties, positing instead that our thoughts are merely modifications of our soul derived from the senses.13