Some general characteristics of philosophy are widely accepted, for example, that it is a form of rational inquiry that is systematic, critical, and tends to reflect on its own methods.
One reason for these difficulties is that the meaning of the term "philosophy" has changed throughout history: it used to include the sciences as its subdisciplines, which are seen as distinct disciplines in the modern discourse.
Others focus on the wideness of its topic, either in the sense that it includes almost every field or based on the idea that it is concerned with the world as a whole or the big questions.
Other approaches see philosophy more in contrast to the sciences as concerned mainly with meaning, understanding, or the clarification of language.
This can take the form of the analysis of language and how it relates to the world, of finding the necessary and sufficient conditions for the applications of technical terms, as the task of identifying what pre-ontological understanding of the world we already have and which a priori conditions of possibility govern all experience, or as a form of therapy that tries to dispel illusions due to the confusing structure of natural language (therapeutic approach, e.g. quietism).
An outlook on philosophy prevalent in the ancient discourse sees it as the love of wisdom expressed in the spiritual practice of developing one's reasoning ability in order to lead a better life.
One difficulty is due to the fact that the meaning of the term "philosophy" has changed a lot in history: it was used in a much wider sense to refer to any form of rational inquiry before the modern age.
[1][2][3] For example, Isaac Newton's Philosophiæ Naturalis Principia Mathematica formulating the laws of classical mechanics carries the term in its title.
[1] Modern definitions of philosophy, as discussed in this article, tend to focus on how the term is used today, i.e. on a more narrow sense.
[5][6][1] Other such characterizations include that it seeks to uncover fundamental truths in these areas using a reasoned approach while also reflecting on its own methods and standards of evidence.
[7][4][14] One difficulty with the deflationist approach is that it is not helpful for solving disagreements on whether a certain new theory or activity qualifies as philosophy since this would seem to be just a matter of convention.
[4] This approach is opposed by essentialists, who contend that a set of features constitutes the essence of philosophy and characterizes all and only its parts.
[4][15] Many of the definitions based on subject matter, method, its relation to science or to meaning and understanding are essentialists conceptions of philosophy.
[4] These difficulties with the deflationist and the essentialist approach have moved some philosophers towards a middle ground, according to which the different parts of philosophy are characterized by family resemblances.
[4][9] The problem with these approaches is usually that they are either too wide, i.e. they include various other disciplines, like empirical sciences or fine arts, in their definition, or too narrow by excluding various parts of philosophy.
Giving a more precise account of the method, for example, as conceptual analysis or phenomenological inquiry, on the other hand, results in a too narrow definition that excludes various parts of philosophy.
[4] Definitions focusing on the domain of inquiry or topic of philosophy often emphasize its wide scope in contrast to the individual sciences.
A similar outlook in the contemporary discourse is sometimes found in experimental philosophers, who reject the exclusive armchair approach and try to base their theories on experiments.
On this view, a field of inquiry belongs to philosophy until it has developed sufficiently to provide exact knowledge of the real elements underlying these appearances.
[1] Karl Jaspers gives a similar characterization by emphasizing the deep disagreements within philosophy in contrast to the sciences, which have achieved the status of generally accepted knowledge.
[4] Some even hold that philosophy as a whole may never outgrow its immature status since humans lack the cognitive faculties to give answers based on solid evidence to the philosophical questions they are considering.
A closely related definition is given by Rudolf Carnap, who sees philosophy as the logic of science, meaning that it is concerned with analyzing scientific concepts and theories.
[4] From the perspective of logical atomism, this clarification takes the form of decomposing propositions into basic elements, which are then correlated to the entities found in the world.
[11] In this sense, philosophy has as its main task to clarify the meanings of the terms we use, often in the form of searching for the necessary and sufficient conditions under which a concept applies to something.
Some focus on its role in helping the practitioner lead a good life: they see philosophy as the spiritual practice of developing one's reasoning ability through which some ideal of health is to be realized.
[39][38] This is based on a conception of what it means to lead a good life that is centered on increasing one's wisdom through various types of spiritual exercises or on the development and usage of reason.
[41] They go beyond science by articulating not just theoretical facts concerning the world but also include practical and ethical components, both on a general and a specific level.
[42][43] On the worldview account of philosophy, it is the task of philosophers to articulate such global visions both of how things on the grand scale hang together and which practical stance we should take towards them.
[11] Another characterization of philosophy sometimes found in the literature is that, at least in principle, it does not take any facts for granted and allows any presupposition to be questioned, including its own methods.
[7] For Immanuel Kant, philosophical inquiry is characterized as "knowledge gained by reason from concepts" (Vernunfterkenntnis aus Begriffen).