The presented article describes the theory of vibrations as we can find it in the work of Joseph Priestley. Priestley was an English polymath of the 18th century, who became known primarily for his controversial political and theological opinions, but also for his proclamation of materialism and determinism. In this article, we will focus on individual areas of his theory of perception and knowledge. It will be described how impressions, sensations and ideas arise and how even more complex operations of the mind can be explained based on this theory – the emergence of abstract ideas, thinking, memory and other mental faculties. We will also focus on the question of how it is possible to connect ideas with body movements and human will.