I will start with a motivation of why scientists might want to care about philosophy in the first place, even though some (Weinberg, Hawking, de Grasse Tyson, Krauss, Dawkins…) think it is worthless. Then I will give a general introduction to the philosophy of science, including the demarcation problem of defining science, issues with scientific explanation and justification, and scientific realism. Finally, I will discuss how cosmology intrinsically needs to rely on philosophical assumptions more than other fields, focusing on a few examples, e.g. the Copernican vs. cosmological principles and the anthropic principle. (Those interested in more may want to check out George Ellis’s “Issues in the Philosophy of Cosmology” http://arxiv.org/abs/astro-ph/0602280.)