David Hume, was and is one of the most influence writers and philosophers in the English speaking world. His philosophy profoundly influenced other philosophers from Kant to Bentham and also scientists from Charles Darwin to Thomas Huxley.
In his own time Hume was far better known as an historian than a philosopher, producing a wildly successful multivolume history of Britain. However it is his philosophical writing that continues to affect thought even into the 21st century. For example, Hume’s essay “Of Miracles” was quoted on a recent scientific podcast.
Hume, along with John Locke and George Berkeley were the “founders” of the school of philosophy known as British Empiricism. For both Locke and Hume people were born “Tabula rasa” or blank slate and that slate was written on by life’s experiences. For Hume these experiences could be of two kinds: ontological or “matters of fact”.
Ontological ideals are self-evident since they can, in short, be only the way that they are. Simple math is ontological; two plus two will always equal four. No amount of misperception may change that simple basic ontology.
“Matters of fact” however are not self-evident and maybe false through either human sensory error or maybe simply untrue. For example, a “matter of fact” is the sun will rise. That may and most likely will happen, but it may not. Also humans not be able to perceive it correctly. However, Hume still believed that human sensory experience while potentially faulty was far superior to second hand knowledge such as merely reading or hearing about an experience. In short, for Hume, seeing a sunrise while potentially misperceived was far superior to reading about or merely hearing about a sunrise.
Hume’s most significant work is without a doubt: “The Enquiry Concerning Human Understanding”. In this in work, he declares that man is the measure of all knowledge: “Even, Mathematics, Natural Philosophy, and Natural Religion, are in some measure dependent on the science of MAN; since the lie under the cognizance of men, and are judged of by their powers and faculties.” In that humans are controlled by the same “laws of nature” that apply any other parts of the universe, but also that those natural laws are only discoverable through human understanding.
Further, a section of “The Enquiry Concerning Human Understanding” titled “Of Miracles” supported general skepticism of religion and could be read as a support for atheism. The essay’s most significant phrase is: “no human testimony can have such force as to prove a miracle and make it a just foundation for any such system of religion.” Hume, in this one short sentence managed to throw into doubt the basis for all religious belief.
Hume, David, A Treatise of Human Nature, Introduction, (1740) http://www.gutenberg.org/files/4705/4705-h/4705-h.htm#2H_INTR
Hume, David, An Enquiry Concerning Human Understanding (1748), Section 10 http://www.gutenberg.org/dirs/etext06/ 8echu10h. htm#section10.
Morris, William Edward. “David Hume”, The Stanford Encyclopedia of Philosophy, ed. Edward N. Zalta, (Fall 2010 Edition) at http://plato.stanford.edu/entries/hume/
Skeptics’ Guide 5X5, The Oct 8 2008 at http://www.theskepticsguide.org/archive/podcast.aspx?mid=2