In the West, Empiricism was developed by John Locke (laws of human nature fame), Berkeley and Hume. The most controversial proposition is that there is no way for us to establish the existence of anything that we can't observe with our senses. In the past, rationalists like Socrates, Plato and Descartes had argued for the existence of substance. Sensory perceptions were secondary and untrustworthy. Hume et. al. basically showed that all such arguments were circular. They repeatedly posed the question, "How do you know?" to all that the rationalists said they knew and concluded that all knowledge is based on our sensory perceptions.

Thus, they refuted the existence of matter. All we know about it or can ever know about it is only by perceiving its qualities. This flew dead against the prevailing rationalist belief at the time which proposed that there existed two kinds of truths/knowledge - one that we observe from our senses and a kind of knowledge whose source is in reason and reason alone. Hume said that human reason can never decipher anything beyond what our senses allow us because human understanding is limited.

In Indian Philosophic tradition, the Charvaka school comes closest to this idea. Out of the six kinds of pramanas that all other schools of philosophy accept, Charvaka accepts only pratyaksha pramana, i.e. direct perception.