This idea highlights the role of experience and evidence, especially perception through the senses. Most empiricists believe that the mind is born with a blank slate, opposed to the rationalist belief that the mind is born with knowledge. The kind of knowledge an empiricist is found through inductive reasoning. Empiricism is often contrasted with rationalism because of their belief system having many aspects different than one another. The concept of a "tabula rasa" (or "clean slate") had been established as early as the 11th Century. A philosopher from Persia named Avicenna, claimed that knowledge is attained through empirical awareness with objects in this world. Through this awareness one theorizes collective concepts. Then the concepts could become more developed through reasoning. Sir Francis Bacon is considered to be an early Empiricist, through his spread of an inductive method for scientific analysis. Today it is know as the scientific method. Colleagues of the British Empiricism School in the late 17th century, David Hume, George Berkeley, and John Locke had become the main advocates of Empiricism. These leaders robustly defended their beliefs of Empiricism against