• Alchemist and Physician Paracelsus (Philippus Aureolus Theophrastus Bombastus von Hohenheim), 1493
• Philosopher and Physician John Locke, 1632

"Paracelsus", meaning "equal to or greater than Celsus", refers to the Roman encyclopedist Aulus Cornelius Celsus from the 1st century, known for his tract on medicine.

Paracelsus was born and raised in the village of Einsiedeln in Switzerland. His father, Wilhelm Bombast von Hohenheim, was a Swabian (German) chemist and physician; his mother was Swiss, she presumably died in his childhood. In 1502 the family moved to Villach, Carinthia, where Paracelsus' father worked as a physician. He received a profound humanistic and theological education by his father, local clerics and the convent school of St. Paul's Abbey in the Lavanttal. At the age of 16 he started studying medicine at the University of Basel, later moving to Vienna. He gained his doctorate degree from the University of Ferrara in 1515 or 1516.

His wanderings as an itinerant physician and sometime journeyman miner took him through Germany, France, Spain, Hungary, the Netherlands, Denmark, Sweden and Russia.

As a physician of the early 16th century, Paracelsus held a natural affinity with the Hermetic, neoplatonic and Pythagorean philosophies central to the Renaissance, a world view exemplified by Marsilio Ficino and Pico della Mirandola. Paracelsus rejected the magic theories of Agrippa and Flamel in his Archidoxes of Magic. Astrology was a very important part of Paracelsus' medicine, and he was a practicing astrologer — as were many of the university trained physicians working at this time in Europe. Paracelsus devoted several sections in his writings to the construction of astrological talismans for curing disease, providing talismans for various maladies as well as talismans for each sign of the Zodiac. He also invented an alphabet called the Alphabet of the Magi, for engraving angelic names upon talismans.

Paracelsus pioneered the use of chemicals and minerals in medicine. He used the name "zink" for the element zinc in about 1526, based on the sharp pointed appearance of its crystals after smelting and the old German word "zinke" for pointed. He used experimentation in learning about the human body. Paracelsus was also responsible for the creation of laudanum, an opium tincture very common until the 19th century.

Paracelsus gained a reputation for being arrogant, and soon garnered the anger of other physicians in Europe. He held the chair of medicine at the University of Basel for less than a year; while there his colleagues became angered by allegations that he had publicly burned traditional medical books. He was forced from the city after a legal dispute over a physician's fee he sued to collect.

He then wandered Europe, Africa and Asia Minor, in the pursuit of hidden knowledge. He revised old manuscripts and wrote new ones, but had trouble finding publishers. In 1536, his Die grosse Wundartznei (The Great Surgery Book) was published and enabled him to regain fame. Paracelsus' life is connected to the birth of Lutheranism, and his opinions on the nature of the universe are better understood within the context of the religious ideas circulating during his lifetime.

He died at the age of 48 of natural causes, and his remains were buried according to his wishes in the cemetery at the church of St Sebastian in Salzburg. His remains are now located in a tomb in the porch of the church.

After his death, the movement of Paracelsianism was seized upon by many wishing to subvert the traditional Galenic physics, and his therapies became more widely known and used.

His motto was "Alterius non sit qui suus esse potest" which means "Let no man belong to another who can belong to himself."

Paracelsus believed in the Greek concept of the four elements, but he also introduced the idea that, on another level, the cosmos is fashioned from three spiritual substances: the tria prima of mercury, sulfur and salt. These substances were not the simple substances we recognize today, but were rather broad principles that gave every object both its inner essence and outward form. Mercury represented the transformative agent (fusibility and volatility); sulfur represented the binding agent between substance and transformation (flammability); and salt represented the solidifying / substantiating agent (fixity and noncombustibility). For example, when a piece of wood is burnt, the products reflect its constitution: smoke reflects mercury, flame reflects sulfur and ash reflects salt.

The tria prima also defined the human identity. Sulfur embodied the soul, (the emotions and desires); salt represented the body; mercury epitomized the spirit (imagination, moral judgment and the higher mental faculties). By understanding the chemical nature of the tria prima, a physician could discover the means of curing disease.

Paracelsus pioneered the use of chemicals and minerals in medicine. His hermetical views were that sickness and health in the body relied on the harmony of man (microcosm) and Nature (macrocosm). He took an approach different from those before him, using this analogy not in the manner of soul - purification but in the manner that humans must have certain balances of minerals in their bodies, and that certain illnesses of the body had chemical remedies that could cure them.

As a result of this hermetical idea of harmony, the universe's macrocosm was represented in every person as a microcosm. According to the insights at the time, there were Seven planets in the sky, Seven metals on Earth and Seven centers (or major organs) in Man — seven was a special number. Everything was heavenly and closely interrelated.

Diseases were caused by poisons brought here from the stars. But 'poisons' were not necessarily something negative, in part because related substances interacted, in part because only the dose determined if a substance was poisonous or not. Evil could expel evil. Therefore, poisons could have beneficial medical effects. Because everything in the universe was interrelated, beneficial medical substances could be found in herbs, minerals and various alchemical combinations hereof. Paracelsus viewed the universe as one coherent organism pervaded by a uniting life - giving spirit, and this in its entirety, Man included, was 'God'. His views put him at odds with the Church, for whom there necessarily had to be a difference between the Creator and the created.

He summarized his own views:

Hippocrates put forward the theory that illness was caused by an imbalance of the four humors: blood, phlegm, black bile and yellow bile. These ideas were further developed by Galen into an extremely influential and highly persistent set of medical beliefs that were to last until the mid 1850s. The dominant medical treatments at Paracelsus' time were specific diets to help in the "cleansing of the putrefied juices" combined with purging and bloodletting to restore the balance of the four humors. Paracelsus supplemented and challenged this view with his beliefs that illness was the result of the body being attacked by outside agents.

Paracelsus' major work On the Miners' Sickness and Other Diseases of Miners documented the occupational hazards of metalworking including treatment and prevention strategies. He also wrote a book on the human body contradicting Galen's ideas.

Paracelsus, sometimes called the father of toxicology, wrote:

German: Alle Ding' sind Gift, und nichts ohn' Gift; allein die Dosis macht, daß ein Ding kein Gift ist.

"All things are poison, and nothing is without poison; only the dose permits something not to be poisonous."

Or, more commonly

"The dose makes the poison."

That is to say, substances considered toxic are harmless in small doses, and conversely an ordinarily harmless substance can be deadly if over - consumed.

Paracelsus is credited as providing the first clinical / scientific mention of the unconscious. In his work Von den Krankeiten he writes: "Thus, the cause of the disease chorea lasciva is a mere opinion and idea, assumed by imagination, affecting those who believe in such a thing. This opinion and idea are the origin of the disease both in children and adults. In children the case is also imagination, based not on thinking but on perceiving, because they have heard or seen something. The reason is this: their sight and hearing are so strong that unconsciously they have fantasies about what they have seen or heard."

Many books mentioning Paracelsus also cite him as the origin of the word "bombastic" to describe his often arrogant speaking style, which the following passage illustrates:

I am Theophrastus, and greater than those to whom you liken me; I am Theophrastus, and in addition I am monarcha medicorum and I can prove to you what you cannot prove... I need not don a coat of mail or a buckler against you, for you are not learned or experienced enough to refute even a word of mine... As for you, you can defend your kingdom with belly - crawling and flattery. How long do you think this will last?... Let me tell you this: every little hair on my neck knows more than you and all your scribes, and my shoe buckles are more learned than your Galen and Avicenna, and my beard has more experience than all your high colleges.

— Paracelsus, Selected Writings

According to the Oxford English Dictionary, the origin of the word "bombastic" is "bombast", an old term for cotton stuffing, rather than a play on Paracelsus's middle name, Bombastus.

Locke's theory of mind is often cited as the origin of modern conceptions of identity and the self, figuring prominently in the work of later philosophers such as Hume, Rousseau and Kant. Locke was the first to define the self through a continuity of consciousness. He postulated that the mind was a blank slate or tabula rasa. Contrary to preexisting Cartesian philosophy, he maintained that we are born without innate ideas, and that knowledge is instead determined only by experience derived from sense perception.

Locke's father, also called John, was a country lawyer and clerk to the Justices of the Peace in Chew Magna, who had served as a captain of cavalry for the Parliamentarian forces during the early part of the English Civil War. His mother was Agnes Keene. Both parents were Puritans. Locke was born on 29 August 1632, in a small thatched cottage by the church in Wrington, Somerset, about twelve miles from Bristol. He was baptized the same day. Soon after Locke's birth, the family moved to the market town of Pensford, about seven miles south of Bristol, where Locke grew up in a rural Tudor house in Belluton.

In 1647, Locke was sent to the prestigious Westminster School in London under the sponsorship of Alexander Popham, a member of Parliament and his father's former commander. After completing his studies there, he was admitted to Christ Church, Oxford. The dean of the college at the time was John Owen, vice chancellor of the university. Although a capable student, Locke was irritated by the undergraduate curriculum of the time. He found the works of modern philosophers, such as René Descartes, more interesting than the classical material taught at the university. Through his friend Richard Lower, whom he knew from the Westminster School, Locke was introduced to medicine and the experimental philosophy being pursued at other universities and in the Royal Society, of which he eventually became a member.

Locke was awarded a bachelor's degree in 1656 and a master's degree in 1658. He obtained a bachelor of medicine in 1674, having studied medicine extensively during his time at Oxford and worked with such noted scientists and thinkers as Robert Boyle, Thomas Willis, Robert Hooke and Richard Lower. In 1666, he met Lord Anthony Ashley Cooper, 1st Earl of Shaftesbury, who had come to Oxford seeking treatment for a liver infection. Cooper was impressed with Locke and persuaded him to become part of his retinue.

Locke had been looking for a career and in 1667 moved into Shaftesbury's home at Exeter House in London, to serve as Lord Ashley's personal physician. In London, Locke resumed his medical studies under the tutelage of Thomas Sydenham. Sydenham had a major effect on Locke's natural philosophical thinking – an effect that would become evident in An Essay Concerning Human Understanding.

Locke's medical knowledge was put to the test when Shaftesbury's liver infection became life threatening. Locke coordinated the advice of several physicians and was probably instrumental in persuading Shaftesbury to undergo an operation (then life threatening itself) to remove the cyst. Shaftesbury survived and prospered, crediting Locke with saving his life.

It was in Shaftesbury's household, during 1671, that the meeting took place, described in the Epistle to the reader of the Essay, which was the genesis of what would later become the Essay. Two extant Drafts still survive from this period. It was also during this time that Locke served as Secretary of the Board of Trade and Plantations and Secretary to the Lords and Proprietors of the Carolinas, helping to shape his ideas on international trade and economics.

Shaftesbury, as a founder of the Whig movement, exerted great influence on Locke's political ideas. Locke became involved in politics when Shaftesbury became Lord Chancellor in 1672. Following Shaftesbury's fall from favor in 1675, Locke spent some time traveling across France as tutor and medical attendant to Caleb Banks. He returned to England in 1679 when Shaftesbury's political fortunes took a brief positive turn. Around this time, most likely at Shaftesbury's prompting, Locke composed the bulk of the Two Treatises of Government. While it was once thought that Locke wrote the Treatises to defend the Glorious Revolution of 1688, recent scholarship has shown that the work was composed well before this date, and it is now viewed as a more general argument against absolute monarchy (particularly as espoused by Robert Filmer and Thomas Hobbes) and for individual consent as the basis of political legitimacy. Though Locke was associated with the influential Whigs, his ideas about natural rights and government are today considered quite revolutionary for that period in English history.

Locke fled to the Netherlands in 1683, under strong suspicion of involvement in the Rye House Plot, although there is little evidence to suggest that he was directly involved in the scheme. In the Netherlands, Locke had time to return to his writing, spending a great deal of time reworking the Essay and composing the Letter on Toleration. Locke did not return home until after the Glorious Revolution. Locke accompanied William of Orange's wife back to England in 1688. The bulk of Locke's publishing took place upon his return from exile – his aforementioned Essay Concerning Human Understanding, the Two Treatises of Civil Government and A Letter Concerning Toleration all appearing in quick succession.

Locke's close friend Lady Masham invited him to join her at the Mashams' country house in Essex. Although his time there was marked by variable health from asthma attacks, he nevertheless became an intellectual hero of the Whigs. During this period he discussed matters with such figures as John Dryden and Isaac Newton.

He died on 28 October 1704, and is buried in the churchyard of the village of High Laver, east of Harlow in Essex, where he had lived in the household of Sir Francis Masham since 1691. Locke never married nor had children.

Events that happened during Locke's lifetime include the English Restoration, the Great Plague of London and the Great Fire of London. He did not quite see the Act of Union of 1707, though the thrones of England and Scotland were held in personal union throughout his lifetime. Constitutional monarchy and parliamentary democracy were in their infancy during Locke's time.

Locke exercised a profound influence on political philosophy, in particular on modern liberalism. Michael Zuckert has argued that Locke launched liberalism by tempering Hobbesian absolutism and clearly separating the realms of Church and State. He had a strong influence on Voltaire who called him "le sage Locke". His arguments concerning liberty and the social contract later influenced the written works of Alexander Hamilton, James Madison, Thomas Jefferson and other Founding Fathers of the United States. In fact, one passage from the Second Treatise is reproduced verbatim in the Declaration of Independence, the reference to a "long train of abuses." Such was Locke's influence that Thomas Jefferson wrote: "Bacon, Locke and Newton ... I consider them as the three greatest men that have ever lived, without any exception, and as having laid the foundation of those superstructures which have been raised in the Physical and Moral sciences". Today, most contemporary libertarians claim Locke as an influence.

But Locke's influence may have been even more profound in the realm of epistemology. Locke redefined subjectivity, or self, and intellectual historians such as Charles Taylor and Jerrold Seigel argue that Locke's An Essay Concerning Human Understanding (1690) marks the beginning of the modern Western conception of the self.

Locke, writing his Letters Concerning Toleration (1689 – 92) in the aftermath of the European wars of religion, formulated a classic reasoning for religious tolerance. Three arguments are central: (1) Earthly judges, the state in particular, and human beings generally, cannot dependably evaluate the truth claims of competing religious standpoints; (2) Even if they could, enforcing a single "true religion" would not have the desired effect, because belief cannot be compelled by violence; (3) Coercing religious uniformity would lead to more social disorder than allowing diversity.

Appraisals of Locke have often been tied to appraisals of liberalism in general, and also to appraisals of the United States. Detractors note that (in 1671) he was a major investor in the English slave trade through the Royal African Company, as well as through his participation in drafting the Fundamental Constitution of the Carolinas while Shaftesbury's secretary, which established a feudal aristocracy and gave a master absolute power over his slaves. For example, Martin Cohen notes that as a secretary to the Council of Trade and Plantations (1673 – 74) and a member of the Board of Trade (1696 – 1700) Locke was, in fact, "one of just half a dozen men who created and supervised both the colonies and their iniquitous systems of servitude". Some see his statements on unenclosed property as having been intended to justify the displacement of the Native Americans. Because of his opposition to aristocracy and slavery in his major writings, he is accused of hypocrisy and racism, or of caring only for the liberty of English capitalists.

Locke uses the word property in both broad and narrow senses. In a broad sense, it covers a wide range of human interests and aspirations; more narrowly, it refers to material goods. He argues that property is a natural right and it is derived from labor.

In Chapter V of his Second Treatise, Locke argues that the individual ownership of goods and property is justified by the labor exerted to produce those goods or utilize property to produce goods beneficial to human society.

Locke stated his belief, in his Second Treatise, that nature on its own provides little of value to society; he provides the implication that the labor expended in the creation of goods gives them their value. This is used as supporting evidence for the interpretation of Locke's labor theory of property as a labor theory of value, in his implication that goods produced by nature are of little value, unless combined with labor in their production and that labor is what gives goods their value.

Locke believed that ownership of property is created by the application of labor. In addition, he believed property precedes government and government cannot "dispose of the estates of the subjects arbitrarily." Karl Marx later critiqued Locke's theory of property in his own social theory.

Locke's political theory was founded on social contract theory. Unlike Thomas Hobbes, Locke believed that human nature is characterized by reason and tolerance. Like Hobbes, Locke believed that human nature allowed men to be selfish. This is apparent with the introduction of currency. In a natural state all people were equal and independent, and everyone had a natural right to defend his “Life, health, Liberty or Possessions". Most scholars trace the phrase, "life, liberty, and the pursuit of happiness," in the American Declaration of Independence to Locke's theory of rights, though other origins have been suggested.

Like Hobbes, Locke assumed that the sole right to defend in the state of nature was not enough, so people established a civil society to resolve conflicts in a civil way with help from government in a state of society. However, Locke never refers to Hobbes by name and may instead have been responding to other writers of the day. Locke also advocated governmental separation of powers and believed that revolution is not only a right but an obligation in some circumstances. These ideas would come to have profound influence on the Declaration of Independence and the Constitution of the United States.

Labor creates property, but it also does contain limits to its accumulation: man’s capacity to produce and man’s capacity to consume. According to Locke, unused property is waste and an offense against nature. However, with the introduction of “durable” goods, men could exchange their excessive perishable goods for goods that would last longer and thus not offend the natural law. The introduction of money marks the culmination of this process. Money makes possible the unlimited accumulation of property without causing waste through spoilage. He also includes gold or silver as money because they may be “hoarded up without injury to anyone,” since they do not spoil or decay in the hands of the possessor. The introduction of money eliminates the limits of accumulation. Locke stresses that inequality has come about by tacit agreement on the use of money, not by the social contract establishing civil society or the law of land regulating property. Locke is aware of a problem posed by unlimited accumulation but does not consider it his task. He just implies that government would function to moderate the conflict between the unlimited accumulation of property and a more nearly equal distribution of wealth and does not say which principles that government should apply to solve this problem. However, not all elements of his thought form a consistent whole. For example, labor theory of value of the Two Treatises of Government stands side by side with the demand - and - supply theory developed in a letter he wrote titled Some Considerations on the Consequences of the Lowering of Interest and the Raising of the Value of Money. Moreover, Locke anchors property in labor but in the end upholds the unlimited accumulation of wealth.

Locke’s general theory of value and price is a supply and demand theory, which was set out in a letter to a Member of Parliament in 1691, titled Some Considerations on the Consequences of the Lowering of Interest and the Raising of the Value of Money. Supply is quantity and demand is rent. “The price of any commodity rises or falls by the proportion of the number of buyer and sellers.” and “that which regulates the price... [of goods] is nothing else but their quantity in proportion to their rent.” The quantity theory of money forms a special case of this general theory. His idea is based on “money answers all things” (Ecclesiastes) or “rent of money is always sufficient, or more than enough,” and “varies very little...” Regardless of whether the demand for money is unlimited or constant, Locke concludes that as far as money is concerned, the demand is exclusively regulated by its quantity. He also investigates the determinants of demand and supply. For supply, goods in general are considered valuable because they can be exchanged, consumed and they must be scarce. For demand, goods are in demand because they yield a flow of income. Locke develops an early theory of capitalization, such as land, which has value because “by its constant production of salable commodities it brings in a certain yearly income.” Demand for money is almost the same as demand for goods or land; it depends on whether money is wanted as medium of exchange or as loanable funds. For medium of exchange “money is capable by exchange to procure us the necessaries or conveniences of life.” For loanable funds, “it comes to be of the same nature with land by yielding a certain yearly income ... or interest.”

Locke distinguishes two functions of money, as a "counter" to measure value, and as a "pledge" to lay claim to goods. He believes that silver and gold, as opposed to paper money, are the appropriate currency for international transactions. Silver and gold, he says, are treated to have equal value by all of humanity and can thus be treated as a pledge by anyone, while the value of paper money is only valid under the government which issues it.

Locke argues that a country should seek a favorable balance of trade, lest it fall behind other countries and suffer a loss in its trade. Since the world money stock grows constantly, a country must constantly seek to enlarge its own stock. Locke develops his theory of foreign exchanges, in addition to commodity movements, there are also movements in country stock of money, and movements of capital determine exchange rates. The latter is less significant and less volatile than commodity movements. As for a country’s money stock, if it is large relative to that of other countries, it will cause the country’s exchange to rise above par, as an export balance would do.

He also prepares estimates of the cash requirements for different economic groups (landholders, laborers and brokers). In each group the cash requirements are closely related to the length of the pay period. He argues the brokers – middlemen – whose activities enlarge the monetary circuit and whose profits eat into the earnings of laborers and landholders, had a negative influence on both one's personal and the public economy that they supposedly contributed to.

Locke defines the self as "that conscious thinking thing, (whatever substance, made up of whether spiritual, or material, simple, or compounded, it matters not) which is sensible, or conscious of pleasure and pain, capable of happiness or misery, and so is concerned for itself, as far as that consciousness extends". He does not, however, ignore "substance", writing that "the body too goes to the making the man." The Lockean self is therefore a self - aware and self - reflective consciousness that is fixed in a body.

In his Essay, Locke explains the gradual unfolding of this conscious mind. Arguing against both the Augustinian view of man as originally sinful and the Cartesian position, which holds that man innately knows basic logical propositions, Locke posits an "empty" mind, a tabula rasa, which is shaped by experience; sensations and reflections being the two sources of all our ideas.

Locke's Some Thoughts Concerning Education is an outline on how to educate this mind: he expresses the belief that education maketh the man, or, more fundamentally, that the mind is an "empty cabinet", with the statement, "I think I may say that of all the men we meet with, nine parts of ten are what they are, good or evil, useful or not, by their education."

Locke also wrote that "the little and almost insensible impressions on our tender infancies have very important and lasting consequences." He argued that the "associations of ideas" that one makes when young are more important than those made later because they are the foundation of the self: they are, put differently, what first mark the tabula rasa. In his Essay, in which is introduced both of these concepts, Locke warns against, for example, letting "a foolish maid" convince a child that "goblins and sprites" are associated with the night for "darkness shall ever afterwards bring with it those frightful ideas, and they shall be so joined, that he can no more bear the one than the other."

"Associationism", as this theory would come to be called, exerted a powerful influence over eighteenth century thought, particularly educational theory, as nearly every educational writer warned parents not to allow their children to develop negative associations. It also led to the development of psychology and other new disciplines with David Hartley's attempt to discover a biological mechanism for associationism in his Observations on Man (1749).

Some scholars have seen Locke's political convictions as deriving from his religious beliefs. Locke's religious trajectory began in Calvinist trinitarianism, but by the time of the Reflections (1695) Locke was advocating not just Socinian views on tolerance but also Socinian Christology; with veiled denial of the preexistence of Christ. However Wainwright (1987) notes that in the posthumously published Paraphrase (1707) Locke's interpretation of one verse, Ephesians 1:10, is markedly different from that of Socinians like Biddle, and may indicate that near the end of his life Locke returned nearer to an Arian position.