The term philosophy derives from the Greek and Greek and Latin words for ‘love of wisdom’. Definition of philosophy is not easy because of diverse views. It is basically a methodological discipline that reflects on the universe and human experience. It can also be defined as a critical study of basic beliefs and concepts.

Agnosticism from Greek for ‘unknowable’ is the doctrine that humans cannot know anything beyond human experience. It involves disinterest in God and religion. The agnostic says he does not know about God whereas an atheist rejects the existence of God.

Cartesianism is a philosophical tradition founded by Rene Descartes. It is rationalist (knowledge can be derived by reason from innate ideas) but is not opposed to empiricism. It considers scientific knowledge to be uncertain and probable. It advocates dualism of the soul and matter. It acknowledges existence of God.

Dialectic is a philosophical concept of evolution applied to various fields of thought. Dialectical materialism is a philosophical approach attributed to Karl Marx and Friedrich Engels. It is based on materialism which they consider the source of ideas as well as mental and spiritual processes. Materialism asserts that all knowledge is obtained by use of senses and by practical experience

Empiricism: Empiricism is the concept that beliefs must be based on actual experience to be valid. If experiences are limited to the sensory, empiricism would deny revelation, intuition, conjecture, and rationalism. If we accept that experiences could be non-sensory such as mental experiences or revelation, then empiricism becomes a wider and more useful concept. Empiricism does not mean repudiation of theory because the best theories are developed from empirical observations. Empiricism should also not deny a priori or innate knowledge and concepts because they can be real. Empiricism should also not deny rationalism because rational reasoning can be based on empirical premises.

Rationalism vs empiricism

Philosophy of science seeks to understand methods of scientific inquiry and to assess their validity. Early Greek philosophers wrote about the philosophy of science. The two trends were clear from the start: the empiricist and the rationalist. Plato and Aristotle were rationalists. Stoics and Epicureans were empiricist. Empiricism was the dominant philosophy in the medieval era and it was found compatible with belief in religion. With the start of the renaissance serious questions about the philosophy of science were investigated. Roger Bacon was an empiricist who asserted was the first to formulate the principles of induction. He preferred observation to deductive reasoning. Francis Bacon (1561-1626) and William of Ockham followed Roger Bacon. Rene Descartes asserted deduction as the mode of scientific reasoning and inquiry. Newton devised the hypothetico-deductive method that did not fully follow the Baconian induction or the Cartesian deduction. Philosophers were divided regarding the nature of Newton’s contributions. Some considered the Newtonian method to be empiricist whereas others considered it to be rationalist. Kant resolved the conflict between the 2 camps by assettng that there is a priori knowledge to which empirical knowledge could be added. He explained Newton’s methods on the basis that a scientist has concepts and categories in his mind that give structure to the knowledge. This then became a basis for theorizing. Logical positivists denied any knowledge from other than sensory experience. Karl Popper rejected inductive generalization and asserted that only falsifiability made a statement empirical. The debate between empiricism and rationalism is the central debate in epistemology and has not yet been laid to rest. Prior non empirical supposition are used in some branches of science and not in others.

Empirical laws and theories

An empirical law is an inductive generalization of observed empirical phenomena that can be tested directly. A scientific theory is a human intellectual attempt to explain observed phenomena in a rational manner and cannot be tested directly. A theory, once established, can be used to deductively derive empirical laws and empirical theorems.

Logical empiricism also called logical positivism is a philosophical doctrine that asserts that scientific knowledge is the only factual knowledge and that any metaphysical knowledge is meaningless. Some empiricists assert that the human mind was a clean slate ‘tabula rasa’ before senses brought it experiences from the environment. Logical positivism considers questions about God and causality cannot be answered.

Enlightenment was an 18^th century European philosophical movement that presented the human as perfect with no limits to human achievement. It made the deity an impersonal force. It argued for human autonomy and use of reason. It caused doubts about the scriptures by subjecting them to critical analysis.

Ethics is a discipline concerned with studying what is morally good and to distinguish it from what is morally bad. It is closely related to religious beliefs. Ethics can be derived from revelation and from human reasoning. Many ethical values are universal among all humans. Many societies codify their ethical principles within the law. There are also ethical principles that are moral teachings and others that are part of culture and social behavior.

Humanism is a term that refers to placing the human at the center of everything. It dis-emphasizes the centrality of God in life. Humanism rejects tradition and seeks objective answers. It places emphasis on the individual. Humanistic ideas have influenced art, science, religion, and philosophy.

Idealism emphasizes the ideal or the spiritual in interpreting human experience. Idealism which sees mind as the only reality, materialism which sees matter as the only reality

Logic, applied: Applied logic is the skill of reasoning correctly following certain rules.

Logic, formal: Formal logic is study structures or logical forms used in deductive arguments. Formal logic is an apriori and not an empirical science.

Metaphysics is study of the real nature of things by going beyond the empirical. Among issues studied by metaphysics are: what really exists, the contrast between reality and appearance, first or irrefutable basic principles. Religions provide answers to issues investigated by metaphysics. Among problems of metaphysics are: the existence of God; interrelations among soul, mind, and body; the conception of the spirit.

Naturalism is a theory stating that all objects and events in the universe are natural and are therefore knowable by scientific investigation. Naturalism denies the supernatural except in a few situations in which the effect of the supernatural can be knowable by scientific investigation.

Nihilism from Latin ‘nothing’ is a philosophy of skepticism that negated authority (state, church, and family) and based its beliefs only on science.

Phenomenology is a philosophical school that asserts that phenomena should be described as consciously experienced without any prior theories, preconceptions, or pre-suppositions.

Phenomenalism asserts that knowledge does not extend beyond perception. There is no existence of an object in the ‘mind’ independent of perception.

Pluralism and monism are two philosophical concepts that are two ends of the spectrum. Monism emphasized the essential unity of all things in the universe. Pluralism emphasizes the multiplicity and diversity of things. In actual practice we can perceive unity in diversity.

Positivism is concept that confines human knowledge to physical experience and excludes any metaphysical influences.

Pragmatism: This is a school of philosophy that asserts that the criterion of merit of ideas is their usefulness, practicability, and consequence. It puts experience above doctrine. It is the opposite of idealism and intellectualism.

Rationalism: Rationalists consider reason to be the main source of knowledge. It asserts that the universe is rational, orderly, and structured. It is contrary to empiricism which asserts that knowledge is from experience especially sensory. Rationalism is also contrary to revelation and intuition. 

Secularism is focus on life on earth and shunning concern with the afterworld. It arose during the reformation as humanism, concern with human affairs and human endeavors on earth. In essence secularism should not be anti-religion but in practice it has been.

Skepticism is doubting of any claim of knowledge. Skeptics challenge any accepted dogmas or views. When applied to religion skepticism means disbelief. In philosophy and science skepticism has played a positive role of forcing those with certain ideas to reexamine and defend or abandon them.

Spiritualism: Spiritualism asserts that there is immaterial reality that cannot be perceived by the senses. It subsumes the following concepts: an infinite personal God, immortality of the soul, immateriality of human intellect and human will. Spiritualism is beyond matter.

Thought is manipulation of symbols using logical operators. The symbols may be verbal or concepts stored in the mind. Thinking essentially is assembling and analyzing information within the mind. The process of thinking needs motivation. If the motivation is internal thought is imagination. If the motivation is external, thinking becomes logical involving making judgments and solving problems. Logical thinking can be inductive (combining several propositions to reach a general conclusion) or deductive (starting from a hypothesis to reach a specific conclusion). Both induction and deduction are used by ordinary humans.