I'm actually sort of fond of logical positivism (LP). In a way, a large portion of this entire work is devoted to a process that sounds like an enormous crowd chanting ``L-P! L-P! All for none, and one for me!'' Or worse, LP on steriods, LP with rabies, LP foaming at the mouth and writhing on the floor near your ankle, snapping at invisible flies.
Not exactly. You see, LP (taken at its face value and with its original and customary proposition) is an axiom that cannot be made consistent with any axiomatic system. For those who came in late or don't remember, LP appears to be the ultimate extension of Hume's empiricism; it incorporates the empirical process itself into the logical process of determining if any assertion is correct, any question is meaningful. It asserts that:
A statement is meaningful if and only if it can be proved true or false, at least in principle, by means of the experience13.22
Because of the fairly obvious connections with the scientific process, LP is a favorite proposition in science classes (especially those on quantum theory, as LP is at the very root of certain interpretations of quantum mechanics and in fact was first stated at very much the same time that quantum theory was being invented and axiomatized). In science it is often expressed as the proposition that questions that cannot be empirically answered by means of a measurement or experiment have no meaning. Curiously, questions that are perfect reasonable ones in our classical experience such as ``where is that baseball and how fast is it going'' are by this criterion meaningless in quantum theory, where one isn't permitted to ask ``where is that electron and how fast is it going''. At least if you want a sensible answer.
The notion of pseudoquestions in the work above, things that might look like questions that can be answered, but really are just sounds, verbal constructs and their associated psychological perceptions that resemble questions grammatically, is clearly ripped off righteously from LP. There, however, the resemblance ends, particularly with respect to the question of meaning. Pseudoquestions are not meaningless - we all understand them perfectly well. This is the fun part - we do understand them but they don't have answers one can find by means of pure reason alone, and hence their answers will always be founded at some level on an unprovable belief, on an axiom.
But, but, but... you sputter13.23.
Yes, there is a razor inside the apple, and it is foolish to take a bite. As we saw in the last chapter, any attempt to establish empirical ``proof'' as a standard of ultimate knowledge both requires dozens of unprovable axioms to establish the basis for empirical proof itself (I've only written down the most important ones above - there are plenty more, recalling that the mathematics required alone for Real Science has several distinct and quite large sets of axioms and definitions) and is inevitably self-referential and hence by its own standard, meaningless, as as I will now proceed to show.
Formal Proof that Logical Positivism is Wrong
This last conclusion is really quite obvious. LP is very lovely as long as you don't use it to define meaning in anything like the way it is used in English in everyday speech, but rather in a specialized sense, heavily dependent on axioms akin to those of not just science but quantum theory (that is, difficult science). Everyone who is (still) reading this understands perfectly well what a proposition like ``God exists'' means, at least as well as they understand the proposition ``A star exists that is outside the event horizon of my own perception''13.26. Neither of which are in principle determinable by experiment.
Unfortunately, the problem with event horizons extends all the way back to every event in space-time13.27. In the strictest possible sense of physics, nothing can be proven by experiments in physics save by interactions, and those interactions instantaneously exclude nearly all events that aren't on the light-cone of any given event. That is, not just the ``things you can see'', but the things you are seeing. LP applied religiously leads you straight back to Hume's far earlier conclusion - all you can know (if that kind of knowledge is the only definition of ``meaning'') is what you are knowing by means of your direct empirical sensory experience. Everything else is inferred, and hence meaningless. We're right back in the Pit.
There is one more extremely humorous argument against LP that I discovered indirectly reading one of the world's great unpublished books on probability theory and inference by Jaynes13.28. In this text Jaynes points out one of the differences between verbal reasoning and boolean logic with the following example:
What a beautiful example! When a Logical Positivist asserts that they only find meaning in what they can empirically validate, what they really mean is that they will deliberately blind themselves to obvious meaning in all cases where meaning exists but empirical validation is impossible. The Logical Positivist very clearly is confused as to the meaning of the word ``meaningless'' in English and common discourse. It is a synonym (not exact, of course, but more or less) of the word ``inconceivable'', and we've already poked a bit of fun at the too-free use of the term ``inconceivable''.
Let's poke just a bit more. Inconceivable literally means that one cannot form the concept within one's mind. There are many ways that this could occur, of course. Also, they are all personal ways - empirical observation is technically limited to one empirical observer at a time, at one instant in space-time - I find meaning in what I can conceive. Finally, only some of these ways are related in any way to empirical evidence or observation, which is why Logical Positivism is just plain wrong.
For example, when I hear somebody speaking Chinese it is meaningless to me, literally inconceivable to my own personal mind.
By this point you, dear reader, should easily be able to understand all of the reasoning above and even figure it out for yourself. The sad truth of the matter is that nothing can be proven by means of experience, as Hume observed about two hundred years before LP was invented. This, of course, means that making a proof by experience the heart of your philosophy as if it could then lead to some insight about the real world is a really, really bad idea, unless you're doing it as some sort of cruel practical joke on generations of students and Academic Deans, or are a bored philosopher down the hall from some quantum theorists and want to have some fun stealing their practical concepts, stripping off all the unwritten axioms, and putting forth the result as something new and different in ``philosophy''...(which is what I rather think is what happened).
As usual, Hume's result is perpetually and eternally forgotten by every school of philosophy that has erupted since his time. If it weren't forgotten, there would be no new schools of philosophy, of course - we could just accept the notion that we don't really ``know'' anything but that which we are perceiving now and can't really know anything but what we are perceiving now plus whatever we choose to infer on the basis of our personal axioms, and spend our philosophical energies constructively in looking for a set of axioms we can all agree upon, in living with them, in playing all sorts of games inferred and deduced from them, without the impossible burden of having to ``prove'' them right.
Of course, it's hard to blame poor Craig, poor Carnap, et. al. for LP, or to blame all the rest of the philosophers from the eighteenth century on who have tried to sweep Hume quietly under the rug. Philosophers have to eat too, after all. Still, it is the hope and intent of this work that once people come to really understand Hume and the Bullshit Nature of Rational Philosophy, they can start working on an axiomatic philosophy where we can replace the impossible notions of logical necessity, proof, and completeness with notions that really are derived from and akin to the axioms of science: degree of belief, consistency and esthetic sensibility.
Empirical proof, even the wishy-washy kind permitted by the ``at least in principle'' in the definition of LP above is ultimately founded in the metaphysical propositions known as the Axiom of Causality and all the rest. By connecting empiricism with knowledge, we conclude that we know Nothing.
Well hell, we already knew that...
On to more fun stuff about what we Don't Really Know.