Philosophy is written in this grand book, which stands continually open before our eyes (I say the 'Universe'), but can not be understood without first learning to comprehend the language and know the characters as it is written. It is written in mathematical language, and its characters are triangles, circles and other geometric figures, without which it is impossible to humanly understand a word; without these one is wandering in a dark labyrinth.

Philosophy is written in this all-encompassing book that is constantly open to our eyes, that is the universe; but it cannot be understood unless one first learns to understand the language and knows the characters in which it is written. It is written in mathematical language, and its characters are triangles, circles, and other geometrical figures; without these it is humanly impossible to understand a word of it, and one wanders in a dark labyrinth.

Philosophy is written in that great book which ever lies before our eyes — I mean the universe — but we cannot understand it if we do not first learn the language and grasp the symbols, in which it is written

Philosophy is written in this grand book, the universe, which stands continually open to our gaze. But the book cannot be understood unless one first learns to comprehend the language and read the characters in which it is written. It is written in the language of mathematics, and its characters are triangles, circles, and other geometric figures without which it is humanly impossible to understand a single word of it; without these one is wandering in a dark labyrinth. — Galileo Galilei, The Assayer, 1623

Philosophy is an attempt to express the infinity of the universe in terms of the limitations of language.

Philosophy is based on speculation, on logic, on thought, on the synthesis of what we know and on the analysis of what we do not know. Philosophy must include within its confines the whole content of science, religion and art. But where can such a philosophy be found? All that we know in our times by the name of philosophy is not philosophy, but merely "critical literature" or the expression of personal opinions, mainly with the aim of overthrowing and destroying other personal opinions. Or, which is still worse, philosophy is nothing but self-satisfied dialectic surrounding itself with an impenetrable barrier of terminology unintelligible to the uninitiated and solving for itself all the problems of the universe without any possibility of proving these explanations or making them intelligible to ordinary mortals.

To present a visible symbol to the eye of another, is not necessarily to inform him of the meaning which that symbol has to you. Hence the philosopher soon superadded to the symbols explanations addressed to the ear, susceptible of more precision, but less effective and impressive than the painted or sculptured forms which he endeavored to explain. Out of these explanations grew by degrees a variety of narrations, whose true object and meaning were gradually forgotten, or lost in contradictions and incongruities. And when these were abandoned, and Philosophy resorted to definitions and formulas, its language was but a more complicated symbolism, attempting in the dark to grapple with and picture ideas impossible to be expressed. For as with the visible symbol, so with the word: to utter it to you does not inform you of the exact meaning which it has to me; and thus religion and philosophy became to a great extent disputes as to the meaning of words. The most abstract expression for Deity, which language can supply, is but a sign or symbol for an object beyond our comprehension, and not more truthful and adequate than the images of Osiris and Vishnu, or their names, except as being less sensuous and explicit We avoid sensuousness, only by resorting to simple negation. We come at last to define spirit by saying that it is not matter. Spirit is — spirit.

Galileo wrote that 'the book of nature is written in the language of mathematics; without its help it is impossible to comprehend a single word of it.'

A successful attempt to express logical propositions by symbols, the laws of whose combinations should be founded upon the laws of the mental processes which they represent, would, so far, be a step towards a philosophical language.

Philosophy is a literary genre.

Symbols and emblems were everywhere. Buildings and pictures were designed to be read like books. Everything stood for something else; if you had the right dictionary, you could read Nature itself. It was hardly surprising to find philosophers using the symbolism of their time to interpret knowledge that came from a mysterious source.

What is philosophy? This is a notoriously difficult question. One of the easiest ways of answering it is to say that philosophy is what philosophers do, and then point to the writings of Plato, Aristotle, Descartes, Hume, Kant, Russell, Wittgenstein, Sartre, and other famous philosophers. However, this answer is unlikely to be of much use to you if you are just beginning the subject, as you probably won’t have read anything by these writers.

Philosophy is but sophisticated poetry.

Philosophy is common sense with big words.