In university courses on philosophy and history, they refer to the Age of Reason, the Age of Enlightenment and the philosophy of Deism. The Age of Reason covers the 1600’s and 1700’s A.D. and the Age of Enlightenment relates to the 1700’s and possibly early 1800’s. There is some overlapping in time and ideas among these two eras. But there also are distinctions between them. Deism was a religious philosophy closely associated with both the Age of Reason and the Enlightenment.
The Age of Reason
The Age of Reason refers to the period in European, British and American history in which the rationalist philosophies of Rene Descartes (1596-1650), Gottfried Leibnitz (1646-1716), Bendedict de Spinoza (1632-1677) and Immanuel Kant (1724-1804) were major influences in the universities and among the highly educated and ruling classes of Europe, Britain and the United States.
Each of these philosophers believed in God but their primary emphasis was on human reason.
Spinoza taught that:
a) supernatural events do not occur.
b) our only knowledge comes from human reason and not from revelation from God.
c) our emphasis should be on nature and not on God.
d) in the realm of ethics and morals, the highest good is equated with our human understanding or reason and humans must conform to the concept of natural law or natural justice. In other words, what humans decided with their human reason was right is right and was wrong is wrong.
From these ideas developed the non-Christian philosophies of Deism, secular humanism and natural law ethics. Even though the Romanticist philosophers of the late 1700’s and early 1800’s did not support rationalism, they found Spinoza’s teachings on ethics and nature attractive. 
The rationalists not only opposed the idea that truth can be obtained by revelation from God through the Bible. They also attacked the empiricist philosophy of 1700’s to 1900’s which stated that truth is obtained only through the experiences of the physical senses.
The Age of Enlightenment
The Age of Enlightenment had its roots in the philosophy of rationalism which was taught by Descartes, Spinoza, Leibnitz and others, but it went beyond these. Here are some of the main features of the so-called Age of Enlightenment:
1. When discussing “What is Enlightenment?”, one of the leaders of the Enlightenment, Kant stated that it was the emergence of the human race from a state of immaturity to a state of maturity. Kant described immaturity as relying on authorities like the Bible, the Church and the State to tell us what to think and do. Maturity was using our own God-given reason and understanding to decide what to think and how to act. Kant said it was an offence to God-given human nature to think and act as the Bible, Church or State commands and instructs us.
2. The Enlightenment philosophers stated that because humans possessed the wonderful God-imparted gift of reason, there was no limit to how far the human race could progress. The advances in science and technology at the time seemed to confirm this idea.
3. The leaders of the Enlightenment said that human reason indicated there were certain natural rights that each human has. Examples of these are life, justice, liberty, equality, property, security and the pursuit of happiness.
While many of these values have a Biblical base, the followers of the Enlightenment often defined these in ways contrary to the Bible’s teachings. For example, their definitions of the concepts of liberty, justice and equality justified various types of wickedness in relation to sex and easy divorce. Their concept of the pursuit of happiness quickly degenerated into a worship of both God-given pleasures and evil perverted usages of these.
4. The philosophers of the Enlightenment taught rightly that God did not appoint kings and queens with the absolute right to command their subjects to do whatever the kings or queens chose. This was an attack on the European idea of the divine right of kings to rule.
5. The Enlightenment philosophers did not agree with many of the teachings of the Bible, but instead followed the teachings of deism. Deism acknowledged God’s existence but taught that humans should choose their own morals, ethics and customs according to the logic of their human reason and in accord with the subjective concept of natural justice.
6. The philosophers of the Enlightenment formulated various humanistic goals or ends for society and taught that the means of achieving these goals must be determined by human reason and not by the Bible.
7. The Enlightenment philosophers taught their followers to also worship modern science’s study of nature. They also stated that the universe was like a machine governed by natural laws which can be discovered by human reason. They said that God had originally created the universe and had given it the laws of nature, but He had left it like a machine to run itself. This why they argued that God does not perform miracles in the natural realm. They believed that if God performed miracles, this would have undermined the supposedly unchangeable natural laws He had originally determined. Another result of such thinking was the Enlightenment philosophers regarded the human body as a machine with natural laws governing it which could supposedly only be properly discovered and dealt with by male doctors. The Enlightenment philosophers assumed males had the superior faculties of reason and logic to females, making males and not females suitable to be doctors.
8. One of the leaders of the Enlightenment was the Frenchman, Jean Jacques Rousseau (1712-1778 A.D.) He was a deist and humanist. He attacked the Biblical teaching on the Fall of Man. He believed that all humans are born basically good, but their wickedness is caused by the corruption of society and by religion, especially Christianity.
Rousseau taught that children should be educated separate from the supposed evil influences of the church. He also said children should be allowed to follow their own natural desires and not be forced by teachers or parents into learning various types of predetermined thoughts and behaviours. He said that teachers were to facilitate the child’s free inquiry about what was true, right and wrong. Teachers were not to teach children that some things were absolutely true, right and wrong.
Like other Deists, Rousseau taught that God exists. But he qualified this by saying that we should test all beliefs and ethics by our own human reason and conscience, and not by the Bible.
Rousseau put his own anti-Christian beliefs into practice in that each time he got his mistress pregnant, he convinced her to leave the babies in a type of orphanage where nearly every resident child died.
9. Francois Voltaire (1694-1778) was another French leader of the Enlightenment. He was a Deist. Therefore he believed in God but rejected most of the teachings of the Bible. He urged tolerance of all religions except the Christian Church. His slogan against the Church was: “Blot out the infamous one”.
10. The Enlightenment had some good effects. For example, it challenged the unbiblical teaching about the supposed God-given right of kings and queens to do whatever they wished. Such wicked teachings were the political foundations in France and Austria up until the French Revolution in 1789 and the 1848 revolutions in Europe.
11. But the Enlightenment had many evil effects. It:
a) led millions of its followers into rejecting Jesus Christ and His teachings.
b) taught millions in Europe, Britain, the United States and Canada to determine their ethics or morals by the reasonings of their own human mind and/or by what they believed their consciences were saying. Because most people in Europe and the above nations rejected the Bible as the source of their morals in the 1700’s and early 1800’s, these were times of dreadful wickedness in these places. The United States had generally better ethical standards in the early 1700’s because of the influence of the Puritans and other sincere Christians who colonised there in the late 1600’s and because of the Great Awakening revival associated with George Whitefield and Jonathon Edwards. But by the late 1700’s, the United States had declined greatly morally and socially.
c) laid the foundation for the French Revolution which replaced the tyranny and evil of the dictatorial French kings with the similar wickedness of the French revolutionaries.
d) laid the foundation for the dictatorship of Napoleon in France and for his constant dreadful wars throughout Europe.
e) encouraged the spread of the cult of Freemasonary throughout many countries. The Freemasons’ religious philosophy fitted in well generally with the thinking of the Enlightenment with its emphasis on God but rejection of Jesus Christ and many of the teachings of the Bible.
f) led to millions beginning to worship science.
g) deceived multitudes into imagining they are basically good people who can bring about the almost unlimited progress of the human race in every area. The latter philosophy experienced revivals in times of peace in the 1800’s and 1900’s. But during the Napoleonic Wars, the First World War and the Second World War, this philosophy was shown to be foolish.
Deism was a very popular religious movement which began in England in the mid 1600’s and spread later to Europe and North America. Deism:
1. taught that God exists and should be worshipped.
2. claimed that true religious and ethical teachings did not come from the Scriptures or from the Church but instead was acquired through the use of God-given human reason. As a result, Deists rejected many basic Christian Biblical teachings and moral standards because they believed these were not confirmed by human reason and scientific research.
3. taught that after God created the universe, He no longer directly intervened in its workings. As a result, Deists said that He does not perform miracles. On the basis of the teaching of Isaac Newton (1642-1747) that the universe is governed by God-given natural laws, the Deists theorised that the universe is a machine with natural laws that even God never changes or suspends.
4. applied the new scientific method or inductive method  of Francis Bacon (1561-1626) to religion and morals. Previously Christians had obtained their beliefs and morals from the Bible and/or the proclamations of the Catholic, Anglican or other churches and/or the logical deductions of their human reason.  But the Deists said all beliefs and ethics must be tested by repeated supposedly “scientific” experiments and social research which examined whether the belief or ethics were true. This sounded so objective but was actually very subjective. Those doing this research often ended up “proving” their own beliefs and ethics which suited their own evil inner desires.
It is no co-incidence that the spread of Deism and the associated philosophies of rationalism and empiricism in the late 1600’s and 1700’s was accompanied by one of the most wicked and immoral periods in the history of Europe and Britain. It was a period in which crime, drunkenness, sexual immorality, pornography, stealing, the murder of newborn and little children, immodest attitudes to exposing breasts and genitals and a lack of concern for the poor abounded.
5. deny the Trinity, the God-given authority of the Bible, the incarnation of Jesus Christ, the atonement of Christ on behalf of fallen humans, the resurrection of Christ and the reality of being born-again of the Holy Spirit.
6. taught that Christ was a good moral teacher but not God.
7. claimed that God was gentle, loving and kind but never would exercise vengeance in judgment.
8. stated that the human soul was immortal and would be rewarded or punished on the basis of good works.
9. taught that all religions were basically the same.
10. stated that tolerance of all religions was a prime virtue.
11. said that it was wrong to be enthusiastic about any religion. Lord Shaftesbury’s “Letter Concerning Enthusiasm” written in 1708 especially spread this idea.
12. claimed that their logic and scientific research showed that humans are basically good and can progress towards perfection in all areas of living through their own natural abilities.
13. began what is called in university circles “the higher criticism of the Bible”.
14. co-operated with Christians in many humanitarian projects to help needy people. The Deists believed in doing certain types of good works and being kind to others.
15. was taught in England by leaders like Lord Herbert of Cherbury (1583-1648), Lord Shaftesbury (1671-1713), John Toland (1670-1722) and David Hume (1711-1776). Between about the mid-1600’s and the end of the 1700’s, Deism dominated the ruling upper classes in England who greatly influenced the laws made through Parliament and the King.
16. spread to Germany through translation of Lord Shaftesbury’s writings. German Deists were Leibnitz, Reimarus, Lessing and Kant. Reimarus was the person who initiated the liberal pursuit of trying to find an historical Jesus who was supposedly not God but only a great moral teacher. 
17. spread to France through the influence of Deists like Voltaire, Rousseau and Denis Diderot (1713-1784).
18. spread to North America through the influence of the Deists Tom Paine, Voltaire, Rousseau, Thomas Jefferson, Benjamin Franklin and George Washington.
A mixture of truth and myth
Many Americans pride themselves on their claim that America was founded as a Christian country. There is a strong element of truth in this in the fact that many of the migrants who came to North America in the 1600’s and early 1700’s, were committed Christians.
But note that by the late 1700’s when the Unites States became an independent self-ruling nation, its ethical standards, laws and Constitution were based more on the teachings of the heretical movement called Deism than on the teachings of Jesus Christ and the Bible.
The Evangelical Dictionary of Theology records the following about prominent American Deists in the 1700’s: “Among great Americans who considered themselves deists were Benjamin Franklin, Thomas Jefferson and George Washington.” 
Note that Benjamin Franklin, George Washington and Thomas Jefferson, were three of the most important American politicians in the late 1700’s who helped to establish what were the features of the American national government, national laws and the American Constitution.
Benjamin Franklin was President of the American state from 1783 – the year the British surrendered in the War of American Independence – to 1788. In 1788, George Washington became the first elected President of the United States and was re-elected against his will in 1792. In 1801, Thomas Jefferson became the third President of the United States and was re-elected in 1805. He retired in 1809.
Note that the Evangelical Dictionary of Theology states: “By the end of the eighteenth century, deism had become a dominant religious attitude among intellectual and upper-class Americans.” Deism’s ethical or moral standards were derived from the religious reasonings of the human mind and not from the revealed written Word of God. Therefore, the ethical standards which underlay the Constitution and most of the national laws of the United States in the late 1700’s and early 1800’s were based on the religious reasonings of the pagan-Christian cult of Deism mixed with a few Biblical standards.
 Walter Elwell (editor), “Evangelical Dictionary of Theology”, Baker, Grand Rapids, 1984, page 1041.
 Ibid, pages 355-356.
 Elwell, “Evangelical Dictionary of Theology”, pages 304-305 and Cairns, pages 406-411.
 Inductive method refers to testing and experimenting with many specific examples in order to work out general principles or theories about what is true.
 I personally do not believe our beliefs and morals can be determined on the basis of the decisions of church denominations or the logical deductions of Christians. Churches should aim to teach what the Scriptures instruct and command.
 Elwell, page 356.
 Ibid, page 304.
 Ibid, page 305.