David Hume (1711 - 1776)

The last of the great triumvirate of “British empiricists” — was also well-known in his own time as an historian and essayist. A master stylist in any genre, Hume's major philosophical works — A Treatise of Human Nature (1739-1740), the Enquiries concerning Human Understanding (1748) and concerning the Principles of Morals (1751), as well as the posthumously published Dialogues concerning Natural Religion (1779) — remain widely and deeply influential. 

Although many of Hume's contemporaries denounced his writings as works of scepticism and atheism, his influence is evident in the moral philosophy and economic writings of his close friend Adam Smith. Hume also awakened Immanuel Kant from his “dogmatic slumbers” and “caused the scales to fall” from Jeremy Bentham's eyes. Charles Darwin counted Hume as a central influence, as did “Darwin's bulldog,” Thomas Henry Huxley. The diverse directions in which these writers took what they gleaned from reading Hume reflect not only the richness of their sources but also the wide range of his empiricism. Today, philosophers recognize Hume as a precursor of contemporary cognitive science, as well as one of the most thoroughgoing exponents of philosophical naturalism.

Leibniz (1646 - 1716)

German philosopher, mathematician, historian and jurist, contemporary of Newton (1642-1727), with whom he feuded bitterly over the invention of calculus. Although Gottfried Leibniz left behind no philosophical magnum opus, he is still considered to be among the giant thinkers of the 17th-century. Leibniz believed in "pre-established harmony" between the outer world and maind, and developed a philosophy of Rationalism by which he attempted to reconcile the existence of matter with the existence of God. Bertrand Russel wrote that Leibniz's intellect "was highly abstract and logical; his greatest claim to fame is as an inventor of the infinitesimal calculus

Leibniz's reflections on epistemological matters do not rival his reflections on logic, metaphysics, divine justice, and natural philosophy in terms of quantity. Nevertheless, he did think deeply about the possibility and nature of human knowledge, and his main doctrines 

Spinoza (1632 - 1677)

       Spinoza is one of the most important philosophers—and certainly the most radical—of the early modern period. His thought combines a commitment to Cartesian metaphysical and epistemological principles with elements from ancient Stoicism and medieval Jewish rationalism into a nonetheless highly original system. His extremely naturalistic views on God, the world, the human being and knowledge serve to ground a moral philosophy centered on the control of the passions leading to virtue and happiness. They also lay the foundations for a strongly democratic political thought and a deep critique of the pretensions of Scripture and sectarian religion. Of all the philosophers of the seventeenth-century, perhaps none have more relevance today than Spinoza.

—His ethics are very similar to Aristotle’s in content and in being eudemonistic. 

—He holds a reductionist and arguably naturalistic understanding of the human being.

—He denies the freedom of the will and transcendent values.

—He tends to subsume the practical under the theoretical.
 

Method of Epistemology:
The admission that there are a variety of ways one can have knowledge.
There is a definitively adequate way for knowing this variety of ways.
—Spinoza’s method has two aspects; one that is formal and another that is more concerned with the concrete perspectives that define the different ways one can have knowledge. 

Knowledge — :

 Adequate vs. Inadequate ideas
3 Types of knowledge

-Imagination: disorganized accumulation of experience

- Reason : logical deductions made based on an understanding of the nature of space (e.g. geometry) or of the nature of thought (e.g. logic, psychology)

-intuition: the intuitive grasp of a particular thing on the basics of ration   

 
Ethics: 

—The polemic against traditional ethics:  

-Against free will

  -Against absolute normative terms 

  -Against teleology 

—The naturalistic replacement: 

  -The human being as conatus 

  -The redefinition of “freedom,” “good,” and “bad” 

  -A special brand of hedonism 

  -Resemblance to Aristotelian virtue ethics 

  -Akrasia and moral knowledge

Rene Descartes (1595-1650)

Rene Descartes was a famous French mathematician, scientist and philosopher. He was arguably the first major philosopher in the modern era to make a serious effort to defeat skepticism. His views about knowledge and certainty, as well as his views about the relationship between mind and body have been very influential over the last three centuries.
Descartes understands doubt as the contrast of certainty. As my certainty increases, my doubt decreases; conversely, as my doubt increases, my certainty decreases. The requirement that knowledge is to be based in complete, or perfect certainty, amounts to requiring a complete absence of doubt — an indubitability, or inability to undermine one's conviction. Descartes' methodic emphasis on doubt, rather than on certainty, marks an epistemological innovation. This so-called ‘method of doubt’