Editing Knowledge (section)

=== ''A priori'' and ''a posteriori'' ===
{{main|A priori and a posteriori}}
The distinction between ''a priori'' and ''a posteriori'' knowledge depends on the role of experience in the processes of formation and justification.<ref>{{multiref | {{harvnb|Stroll|2023|loc=§ A Priori and a Posteriori Knowledge}} | {{harvnb|Baehr|2022|loc=Lead Section}} | {{harvnb|Russell|2020|loc=Lead Section}} }}</ref> To know something ''a posteriori'' means to know it based on experience.<ref>{{multiref | {{harvnb|Baehr|2022|loc=Lead Section}} | {{harvnb|Moser|2016|loc=Lead Section}} }}</ref> For example, by seeing that it rains outside or hearing that the baby is crying, one acquires ''a posteriori'' knowledge of these facts.<ref>{{harvnb|Baehr|2022|loc=Lead Section}}</ref> ''A priori'' knowledge is possible without any experience to justify or support the known proposition.<ref>{{multiref | {{harvnb|Russell|2020|loc=Lead Section}} | {{harvnb|Baehr|2022|loc=Lead Section}} }}</ref> Mathematical knowledge, such as that 2 + 2 = 4, is traditionally taken to be ''a priori'' knowledge since no empirical investigation is necessary to confirm this fact. In this regard, ''a posteriori'' knowledge is empirical knowledge while ''a priori'' knowledge is non-empirical knowledge.<ref>{{harvnb|Moser|2016|loc=Lead Section}}</ref>

The relevant experience in question is primarily identified with [[Experience#Perception|sensory experience]]. Some non-sensory experiences, like memory and introspection, are often included as well. Some conscious phenomena are excluded from the relevant experience, like rational insight. For example, conscious thought processes may be required to arrive at ''a priori'' knowledge regarding the solution of mathematical problems, like when performing [[mental arithmetic]] to multiply two numbers.<ref>{{multiref | {{harvnb|Baehr|2022|loc=§ 1. An Initial Characterization, § 4. The Relevant Sense of 'Experience'}} | {{harvnb|Russell|2020|loc=§ 4.1 A Priori Justification Is Justification That Is Independent of Experience}} }}</ref> The same is the case for the experience needed to learn the words through which the claim is expressed. For example, knowing that "all bachelors are unmarried" is ''a priori'' knowledge because no sensory experience is necessary to confirm this fact even though experience was needed to learn the meanings of the words "bachelor" and "unmarried".<ref>{{multiref | {{harvnb|Baehr|2022}} | {{harvnb|Russell|2020|loc=§ 4.1 A Priori Justification Is Justification That Is Independent of Experience}} }}</ref>

It is difficult to explain how ''a priori'' knowledge is possible and some empiricists deny it exists. It is usually seen as unproblematic that one can come to know things through experience, but it is not clear how knowledge is possible without experience. One of the earliest solutions to this problem comes from [[Plato]], who argues that the soul already possesses the knowledge and just needs to recollect, or remember, it to access it again.<ref>{{multiref | {{harvnb|Woolf|2013|pp=[https://academic.oup.com/mind/article/122/485/171/961176 192–193]}} | {{harvnb|Hirschberger|2019|p=[https://books.google.com/books?id=LWGlDwAAQBAJ&pg=PT22 22]}} }}</ref> A similar explanation is given by [[Descartes]], who holds that ''a priori'' knowledge exists as [[innate knowledge]] present in the [[mind]] of each human.<ref>{{multiref | {{harvnb|Moser|1998|loc=§ 2. Innate concepts, certainty and the a priori}} | {{harvnb|Markie|1998|loc=§ 2. Innate ideas}} | {{harvnb|O'Brien|2006|p=[https://books.google.com/books?id=TOQcebWMstwC&pg=PA31 31]}} | {{harvnb|Markie|Folescu|2023|loc=§ 2. The Intuition/Deduction Thesis}} }}</ref> A further approach posits a special mental faculty responsible for this type of knowledge, often referred to as [[rational intuition]] or rational insight.<ref>{{harvnb|Baehr|2022|loc=§ 1. An Initial Characterization, § 6. Positive Characterizations of the A Priori}}</ref>