Positivism vs. Constructivism
Some epistemological postures consider the object “knowledge” in a radically different way:
- the positivist posture considers the truth value of propositional knowledge representing reality as independent of the will of men, without metaphysical content and where a “good verbalization of reality” would be necessary without the desiderata or the subjectivity of a decision-maker. have to intervene. (eg Ohm U = RI law in electricity, fundamental principle of the dynamics F = ma in mechanics, equation E = mc2 in relativity, …). This posture is generally well adapted for the knowledge of the exact sciences (ex: physics, chemistry, biology, …),
- the constructivist posture, following Kant, considers knowledge as the product of the human understanding.
Foundationism and coherentism
The debate between foundationalism and coherence is about the structure of epistemic justification.
The starting point of the debate is Agrippa’s problem: if someone makes a statement, then he must defend it with a justification or an argument. But this justification itself contains an affirmation, which must be justified in its turn. And so on. In the long term, only three situations are possible: 1) the justification stops at certain affirmations that are not themselves justified, 2) the justification goes on forever, or 3) the justification is based on circular statements that she had to justify. This problem is often called Agrippa’s trilemma, because it was formulated by the skeptical philosopher Agrippa, and reached us through Sextus Empiricus. At Agrippa, these three options are among the five “modes” by which the skeptic can suspend any affirmation. Agrippa holds them all three as bad, and names them respectively: the hypothesis (also called the dogmatic judgment), the regression to infinity, and the vicious circle. Agrippa’s trilemma is also known as the trilemma of Fries (after Jakob Friedrich Fries, the first to formulate it as a trilemma), the trilemma of Münchhausen (after the story of Baron von Münchhausen extricating itself from a marsh by raising itself by the hair), or problem (or argument) of the epistemic regression.
Foundationalism consists in accepting the first branch of the trilemma. According to this position, certain beliefs (basic beliefs) justify our beliefs without being themselves justified by other beliefs. Fundamentalists must admit that basic beliefs are unjustified, or they must argue that they are justified in some other way than an argument (for example, by sensory experience, intuition, or evidence). Also differ among themselves on the class of beliefs that constitute basic beliefs. For Descartes and the Cartesians, it is a small number of abstract principles, the knowledge of our own existence, and the truth of God. For empiricist philosophers like David Hume or Bertrand Russell, these are the beliefs from sensory experience. Recently, foundationalism has been championed by Roderick Chisholm.
Coherentism consists in accepting the third branch of the trilemma. According to this position, beliefs can be exchanged for one another. The idea of coherentism, which can be traced back to Hegel, was defended by Otto Neurath, who compared science to a boat at sea which can be replaced one by one, but without ever rebuilding it entirely from nothing. The main contemporary defender of coherentism is Keith Lehrer.
Infinitism consists in accepting infinite chains of justifications. This position has had few followers. It is now defended by Peter Klein.
The conceptions that foundationalism and coherentism are of the structure of epistemic justification are illustrated by well-known images. In an important article, Ernest Sosa uses those of the raft and the pyramid. According to the coherentism, our beliefs are in the image of a raft whose parts are maintained mutually, without any one serving support without being supported itself. According to the foundationalism, our beliefs are like a pyramid, where a base supports the rest of the building. The image of the pyramid is particularly relevant to empiricist foundationalism, in which basic beliefs are the many particular beliefs we acquire through the use of the senses. For a rationalist foundationalism, where basic beliefs are a small number of principles on which one attempts to found all others, the image of the tree, borrowed from Descartes, is more appropriate.
Contextualism and invariantism
Contextualism in the philosophy of knowledge is the thesis according to which the attributions of knowledge can change values of truth from one context of conversation to another.
Contextualism was first and foremost defended as a solution to the problem of skepticism. According to the contextualists, when we look at skeptical scenarios like being dreamed of, being the victim of a Malin Genie or being a brain in a tank, the word “knowing” takes on a very restrictive value, so that the statement “Peter knows he has two hands” becomes false in this conversation. Conversely, in everyday conversations, the word “knowing” has a less restrictive value, so that the statement “Peter knows he has two hands” may be true. But, according to the contextualist, even if these two statements are made about the same person in the same situation, it is possible that one is true and the other is false, because the word “know” has changed meaning between the two conversations.
The contextualist compares the word “knowledge” with other context-sensitive words, that is, changes in value from one conversation context to another: indexicals (“I”, “you”, “he”) or so-called “gradable” adjectives, which refer to a certain quantity on a scale, as “big” or “rich”.
The main advocates of epistemic contextualism are David Lewis, Stewart Cohen and Keith DeRose.
In contrast, invariantists are the positions that deny that the value of “knowing” can change from context to context. According to the invariantists, if what the skeptic says is true then what we say in our current attributions of knowledge is false, and vice versa.
One can also place in the contextualist a distinct set of Welsgensteinist positions, according to which the attributions of knowledge are justified only in relation to certain practices of justification accepted by the linguistic community. In this category you can find the On Certainty of Wittgenstein, John Austin, Michael Williams or even Robert Fogelin.
The sources of knowledge
The empiricist philosopher (see John Locke, David Hume) places the sensory experience at the origin of the acquisition of knowledge. For its part, the rationalist (see Rene Descartes, Karl Popper, Julius Vuillemin) makes it based on the exercise of reason. There is also a re-union or synthesis of the sensible (Percept) and of the reason (Concept) in authors like Rudolf Steiner (in his “Philosophy of Freedom“), Schelling. Bringing together the two elements would be both the origin and the very act of “knowing” made effective by “thinking”.
For example, the idealist will see the world of ideas as the primary element of all things while the spiritualist will retort “no, the world of ideas comes from the first source which is the Divine”. As for the realist – in front of these remarks which will be insignificant to him – he will be satisfied simply of what he has before the eyes (sensory aspect).