  Mach’s empiricism is complicated. It has its roots in the belief that knowledge is a product of evolution, that our senses, minds, and cultures have an evolutionary history. It was simple experience to which early organisms responded, and it was out of simple experiences that the first images of the world were constructed. These constructions became a priori, allowing new and more complicated understandings, and so forth. This process is in a sense repeated in development; individual development begins through a process of the interaction of simple sensations with those innate capacities formed in our ancestors. Out of this, more complex understandings arise; the process continues. Science furthers this biological process by bringing our primitive conceptions into contact with new environments, thus causing mental adaptation. The one and same process unites all features of activity in nature: the adaptation of early life to primordial environments and the adaptation of modern science to new data are unified under the principle of experience forcing adaptation in memory. Though loosely an empiricist in this sense, he rejected Locke’s tabula rasa, and aligned himself against the more empiricist Helmholtz and towards the nativist Ewald Hering in their famous nature-nurture debates. He is not in the least a traditional empiricist.