Natural science uses valid scientific methodology and supporting evidence to build testable explanations about the world. Pseudoscience lacks this methodology and evidence. Examples of natural science include physics, chemistry, and biology, while pseudoscience examples are astrology, creationism, crystology, and graphyology. Astrology in particular is considered pseudoscience because it is not scientifically proven, can involve confirmation bias, makes vague claims, and uses exceptions in a flexible way, rather than being falsifiable.