Philosophy of science does not use the scientific method to empirically derive ideas about the physical world through conducting experiments and interpreting results. However, it is still about science with an emphasis on the logic and rationality behind science itself, bringing to light what cannot be explained by empirical measures. It is also metaphysically and epistemologically focused on all humans while incorporating the nature and essence of human knowledge. Just as the philosophy of science is to science, theoretical psychology is to psychology in that it is the logic and rationality applied to concepts, laws, and theories. Theoretical psychology is not in place to discern which theories are more truthful or more correctly. Many consider theoretical psychology as the support or rationalization of an "idea" within psychological theory that is more "truthful". However, this is not the case. Theoretical psychology is scientifically grounded in ideas of what is known through epistemology. Theoretical psychology existed long before any branches of traditional empirical and experimental psychology. Because of this, there is much more depth and breadth of knowledge from which to draw. This also makes it less common for new developments to come about in the present day because many "new" approaches are drawing from and revitalizing past theories. This brings new knowledge, frames of reference, and mindsets to these foundational theories. This may be due to Ideas taking longer to develop and gain momentum than related fields in empirical based psychology. Theoretical psychology is a rational, non-experimental approach to psychology. In psychology, as with any field of study, there are three philosophical perspectives and methodologies of ways to derive knowledge about the reality of the world. Rationalism (use of intellect and reason of the mind), Empiricism (use of our individually experienced sensorium), and Skepticism (knowledge beyond mere appearance that is not able to be studied) characterize the three perspectives in understanding theoretical concepts relating to laws which help to understand larger theoretical theories. Of the philosophical perspectives, rationalism is the most pertinent to this discipline of psychology. Theoretical psychology is not experimental or clinically based and focuses on non-experimental ways to acquire knowledge about psychological topics. It explores the theoretical knowledge behind its encompassed ideologies. Oftentimes this includes, but is not limited to, non-experimental critiques to different schools of thought, and the usefulness of psychological concepts. Theoretical psychology is a discipline that bases its information through inference, as opposed to empirically acquired information. Hypotheses are then exchanged and further built upon from different perspectives.