The questions pondered by philosophy since Thales eventually engendered "natural philosophy," as modern science was originally called. Scientific method since Bacon and Galileo pursues those questions in an increasingly well-defined, limited, credentialed, and conditional manner.
Science offers clear standards for what is accepted as subject matter and "knowledge" in its different disciplines. When these standards are applied, the practice becomes "science" and the "remainder," we might say, is philosophy... which has its own standards, methods, etc., but does not restrict its subject matter or necessarily accept the inductive, conditional, experimental limits to "knowledge."
Nonetheless, most professional philosophers remain keenly interested in and knowledgeable about progress in science and mathematics. Many address those issues in science that practicing scientists themselves are not necessarily concerned with. These might include the epistemological structure of scientific evidence or the ontological status of entities like "fields" or "genes." The questions of "how do you know?" or "what is it really?" are largely excised from science, since they can endlessly regress into skepticism.
In the analytical and empirical traditions, from Locke to the logical empiricists, many philosophers have seen their role as the conceptual clarification and justification of the sciences, toilers who "clear the brush" for science, as Locke put it. Most scientists, it must be said, do not regard this as an especially helpful or useful function. As philosopher Mary Midgley puts it, "philosophy is like plumbing." Everybody takes it for granted, nobody cares to think about it, until some connection breaks!
In philosophy, moreover, nothing goes out of date. Philosophy retains and studies its own history. But as the literature grows, philosophy too undergoes division of labor and specialization. Leibniz was reputedly the last man to "know everything" and Hegel the last philosopher to "know all of philosophy." So today many areas of philosophy have no particular need to keep up with science and math. Indeed, most scientists today cannot keep up with science and math. Philosophers who work in logic, ethics, language, political philosophy, phenomenology, hermeneutics, or history of philosophy don't need to subscribe to Nature or Scientific American.
Minus consensus or experimental validation, what good is philosophy? Well, its gedanken experiments are at least affordable. According to a joke circulating in physics departments, the university Dean complains bitterly about the cost of physics: "Why do you physicists need all this expensive equipment? The math department only needs pencils and a waste basket. And the philosophy department doesn't even need the waste basket!"