Philosophy of Science as Developed by Empiricists David Hume and Logical Positivist Group

¶ … philosophy of science as developed by empiricists such as David Hume and completed by the logical positivist group. Why do they think truth can be best found by using the senses, the experimental method, and probability? Explain the verifiability theory and its meaning for such subjects as God, the super-natural, justice, morality, and political science. What are the advantages and the limitations of this philosophical view?

The "Verifiability" or "Verificationist Theory of meaning" states that to understand a statement and to verify it one must first begin with a statement that can be proven true or false through sensory data. (Logic: The Verifiablity Theory of Meaning, 2004) In the Empiricist philosophy towards science, the source of all meaning is ultimately human sensory experience. Only meaningful statements can be true or false. Only statements whose meaning can be verified in observational terms can be true or false. This is in contrast to 18th and 19th century speculative metaphysics. This school involved attempts to answer notions as to the nature of the absolute, or the nature of when something was nothing. Such metaphysics needed to be distinguished from genuine science, in the view of Hume and later, the Logical Positivists. (Logical Positivism, 2004)

Logical Positivists wanted to distinguish science from religion, metaphysics (conceived of as an attempt in philosophy to defend views about the nature of reality through reason alone), and pseudo-science like astrology. But Hume and the Logical Positivists also wanted to contradict the importance of deductive statements in philosophy. They believed that merely logical truths were trivial in the sense that they tell us nothing about the nature of the world. "Any sentence of the form 'Either P. Or not P', for instance, is a basic logical truth. But, like all merely logical truths sentences having this form assert nothing about how the world is." (Logical Positivism, 2004)

Instead, to prove a statement about the world, one must be able to prove it true or false in the specific context in which it is true. If there is no way to test the validity of a statement, and the statement is merely a deductive postulate in a logical syllogism, the statement is ultimately irrelevant and therefore meaningless. This is in contrast to the "Deductively Valid Inference" theory of the Rationalists which stated that "an inference such that there is no possible way in which the premises could be true and the conclusion false, it must be true. But Empiricists were interested in what "we only know what we have proven or observed thus far." When there is "no way to know if there will be a case in the future (or current case that is unknowable) where the same premises lead to a different conclusion," other than making a proposition, again, the statement is meaningless. The world's real circumstances, unlike numbers or abstract Ps or not-Ps, are always in a state of flux. (Boyd, 2004)

Empiricists stressed the need to verify statements with sensory data in all possible situations, thus providing one of the founding philosophies of the sceintific method of experimentation. Hume, stressed that all the materials of thinking, also known as perceptions are derived either from sensation or "outward sentiment" or from reflection otherwise known as "inward sentiment." Hume divided perceptions into two categories, distinguished by their different degrees of force and vivacity. Our "more feeble" perceptions, ideas, were ultimately derived from our livelier impressions. One can only imagine a horse after one has seen a horse in life, or at least a picture of one. (Morris, 2001)

Hume calls ideas feebler because of his copy thesis; he argues that all ideas are ultimately copied from impressions. That is, for any idea we select, we can trace the component parts of that idea to some external sensation or internal feeling. Thus, ideas are always once removed from the truth -- an idea of a horse is inferior when produced from a copy, as opposed to the sight of a real thing. (Feiser, 2004)