cofty
So basically just maths then?
Math is the subject least prone to error, but logic, as a subset of math, can also help us with other questions that I don't think would be easily amenable to scientific experiments. Just off the top of my head:
What is matter? What would its properties be if it could exist in a higher spacial dimension? Or what if we removed a dimension? Is matter infinitely reducible to smaller and smaller components or are their fundamental particles that cannot be reduced any further? And how does matter relate to consciousness? Is consciousness an epiphenomena of matter arranged in a particular configuration or is it essentially independent of matter? Can consciousness survive the destruction of the body? Is there a God? If there is, what would such a being be like?
These questions are much harder to answer than any math problem. Most of them are actually interdependent on one another and so could not be answered in isolation; in fact, even a single wrong answer could through off the entire equation! But these questions are nonetheless amenable to a sustained exercise of logical deduction. I will not try to answer any of them here (that would require an entire book at least!) but I encourage anyone who is interested to read Aristotle's Logic, Plato's Dialogues, Plotinus' Enneads, René Descartes' Meditations on the First Philosophy, Baruch Spinoza's Ethica and Wilhelm Leibniz's Metaphysics and Monadology. I strongly recommend George MacDonald Ross' excellent survey of Leibniz's thought. His book, Leibniz, is long out of print, but can still be obtained via the interlibrary loan system. There is also a decent ebook on Leibniz available from Amazon by Mike Hockney: The Last Man Who Knew Everything. Hockney is a good enough writer and very brilliant, but in my opinion he wastes a lot of space criticizing anyone who disagrees with his views.
There is a logical progression in the works of these thinkers and those who are patient and willing to think through the questions they raise, using their own powers of deduction, will find the answers to these questions and many more besides. None of these philisophers got everything right. They all made mistakes. But philosophy is not dogmatic like religion. Properly, there should be no Platonists, Aristotelians or Nietzschians. Don't read them looking for answers. Read them so you'll know which questions to ask so you can arrive at your own answers!