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As we will see, their ambitions were even grander since they also argued that much of what was going on in philosophy at the time was literally meaningless.
We will consider three central projects taken on by the Positivists in developing their Empiricist view of scientific knowledge.
These are the demarcation problem, the problem of distinguishing science from non-science, developing a view about what a scientific theory is, and giving an account of scientific explanation. The Positivists utilize the resources of symbolic logic in each of these projects.
The Demarcation Problem
Among the main tasks the Positivists set for themselves was that of distinguishing legitimate science from other rather suspect fields and methods of human inquiry. Specifically, they wanted to distinguish science from religion, metaphysics, and pseudo-science like astrology.
19th century German metaphysics involved attempts to reason about such obscure notions as “the absolute,” or the nature of “the nothing.” Such metaphysics needed to be distinguished from genuine science. We had also seen appeal to obscure empirically suspicious entities and forces in Aristotelian science such as the “vital force” to explain life, or the “dormative virtue” a mysterious power of substances like opium to cause sleep. Such mysterious forces needed to be eliminated from genuine scientific discourse.
While metaphysics and talk of obscure forces in science were to be distinguished from genuine science, the Positivists needed to preserve a role for unobservable theoretical entities like atoms and electrons. The rejection of metaphysics and obscure forces must not undermine the legitimate role for theoretical entities.
The Positivists employed Empiricism in their proposed solution to the demarcation problem. Empiricism, as we know, is just the view that our sense experience is the ultimate source of justification for all of our factual knowledge of the world. The Positivists extend Empiricism to cover not just the justification of knowledge, but the meaningfulness of language as well. That is, they take the source of all meaning to ultimately be our sense experience. Only meaningful statements can be true or false. So, only statements whose meaning can ultimately be given in observational terms can be true or false. Theoretical terms like “atom” refer to things we can’t directly observe. But talk about such theoretical entities could be made empirically respectable by means of observational tests for when theoretical terms are being appropriately applied. Electrical charge, for instance, is not itself observable. But we can define theoretical terms in terms of observational tests for determining whether the term applies. So we might say that a thing is in a state of electrical charge if it registers voltage when electrodes are attached and hooked up to a voltage meter. Similarly, though you don’t directly observe the state of charge of a battery, you can easily carry out a test in observat