David Hume published Books I and II of A Treatise of Human Nature anonymously, in 1739, when he was twenty-eight years old. The first substantive English review of the work appeared later the same year, in a publication called History of the Works of the Learned...He complained about Hume's "inscrutability."
A few weeks before he died, two hundred years ago, Hume told Boswell that he "never had entertained any belief in Religion since he began to read Locke and Clarke." It is almost certain that Hume was reading these authors in his early twenties, when he was already at work on A Treatise of Human Nature.
Most modern studies of Hume have concentrated on the philosophy he advanced in A Treatise of Human Nature, the Enquiries Concerning Human Understanding and Concerning the Principles of Morals, and the Dialogues Concerning Natural Religion. Of these works, certainly the Treatise has been the one most carefully scrutinized and annotated, even in spite of the fact that late in his life Hume repudiated his magnum opus and advised his readers to look elsewhere for his philosophy.
Hume thinks that common-sense beliefs are false and are shown to be false by scientific investigation. For example, he thinks that ordinary people hold that there is chance in the universe. But for Hume, as well as many other eighteenth-century philosophers, 'what the vulgar call chance is nothing but a secret and conceal'd cause.'
The Philosopher David Hume is famous for making us realize that until we know the necessary connection/cause of things then all human knowledge is uncertain, merely a habit of thinking based upon repeated observation (induction), and which depends upon the future being like the past.
Hume's position in ethics, which is based on his empiricist theory of the mind, is best known for asserting four theses: (1) Reason alone cannot be a motive to the will, but rather is the “slave of the passions." (2) Moral distinctions are not derived from reason. (3) Moral distinctions are derived from the moral sentiments: feelings of approval (esteem, praise) and disapproval (blame) felt by spectators who contemplate a character trait or action. (4) While some virtues and vices are natural, others, including justice, are artificial.
Hume carried the empiricism of Locke and George Berkeley to the logical extreme of radical skepticism. He repudiated the possibility of certain knowledge, finding in the mind nothing but a series of sensations, and held that cause-and-effect in the natural world derives solely from the conjunction of two impressions. Hume's skepticism is also evident in his writings on religion, in which he rejected any rational or natural theology.
He was raised from an early age by his widowed Calvinist mother and attended Edinburgh University. His self-description in his five-page autobiography holds to be quite honest, “a man of mild Dispositions, of Command of Temper, of an open, social, and cheerful Humour, capable of Attachment, but little susceptible of Enmity, and of great Moderation in all my passions.”
Hume is arguably the most influential philosopher ever to write in the English language. An arch empiricist, he believed that all knowledge comes from sense experience, therefore there is neither innate knowledge nor innate concepts, and that metaphysical speculation was but sophistry and illusion.
All human reasonings or inquiries involve either 'knowledge' or 'probability'. In the Enquiry Concerning Human Understanding Hume discusses this in terms of the distinction between 'relations of ideas' and 'matters of fact' (this is often referred to as 'Hume's fork'.). Relations of ideas are typically mathematical or logical and cannot be denied without contradiction (for example, 3 x 5 = 1/2 of 30)...Matters of fact (for example, that the sun will rise tomorrow), on the other hand, are discovered by observation and non-demonstrative inference and can be denied without contradiction.