An attack on philosophy

After reading Ayer's Language, Truth and Logic, everything became clear. I realised, then, that I no longer wanted to study philosophy. The following argument shows a major problem with philosophy:

1. The only way to know anything about the world is to derive information through the senses. This is why science places so much importance on experiment and observation.

2. Philosophy is a discipline with the primary aim of discovering truth about the world.

3. The method of philosophy is to derive propositions from intuitively plausible premises (not information from the senses).

4. Therefore, it is impossible for philosophy to achieve its aim.

Premise 4 is derived from all premises 1, 2 and 3. So if the reader believes in the first 3 premises, then they are forced to the conclusion that there is something fundamentally wrong with philosophy. It is, as Ayer put it, a nonsensical field (although Ayer was speaking of Metaphysics in particular).

It may help to go through some of the premises more carefully. Of course, the first premise is empirical in spirit. Any rationalist would reject it in an instant. One might object to premise by claiming that mathematical knowledge is a counter-example. Mathematical propositions, it appears, can be 'discovered' without any reference to sensory experience.

Ah, but here is the problem. Mathematical propositions tell us nothing about the real world. They tell us what the axioms imply. They are true by definition. All of mathematics can be deduced to a claim that if so and so axioms are true, then these results are true. But this says nothing about what is actually true.

One might respond to this by arguing that Mathematics has many applications in the real world, especially in physical explanations. Surely, Mathematical knowledge tells us something about the real world. But this is not so. Whether mathematical models apply to the real world is an empirical matter. Mathematical propositions or logical propositions therefore tell us nothing prima facie about the world.

The second premise represents the philosphy which I am interested in. If there are any fields of philosophy which do not satisfy this category, then I have no qualms about them.

The third premise is the one which separates philosophy from science. These two disciplines do, I believe, have the common aim of discovering truth. The former, however, aims to do so without any connection to the world; as though the mind itself is sufficient to discover universal truths. This is the issue I take with philosophy. Of course, one might argue that what I am writing now is philosophical, and thus refutes my own argument.

The power of this response makes me rethink the nature of my argument. I guess I would defend my argument by claiming that my first three premises are observations that I have made, and are thus empirical. So my argument is not entirely philosophical (at least not philsophical according to my argument).