impression

In philosophy, an "impression" refers to a perception experienced with great force or vividness, as distinguished from an "idea," which is a fainter copy of an impression. This distinction was notably explored by philosopher David Hume. Impressions can be simple or complex, and Hume posited that simple impressions are the direct cause of their corresponding simple ideas.1

Impressions can arise from sensation (from unknown external causes) or reflection (from internal mental states like pleasure or pain). The way we form thoughts is guided by principles like resemblance, contiguity, and cause and effect, which help us associate ideas. This philosophical concept of impression is distinct from its common usage, which can mean a physical trace or a general notion or remembrance.1234