Londoner wrote:If we are discussing where people normally get their beliefs from, then certainly you would include testimony. But that is to describe people, not the beliefs. I accept people do believe in astrology, I can guess why they came to believe in astrology but I do not accept that their belief is justified. If we are to say they are 'justified' we would be using 'justified' to mean something different, like 'what they would say if asked where their belief originated'.
We might trust what we have been told, but we do not trust it because we have been told it. What we are trusting is that the person who is telling us is reporting some information that ultimately rests on something other than hearsay.
In the quoted passage he writes 'Many testimony-based beliefs are justified or constitute knowledge' To say that is to allow that there is no link between testimony and knowledge. The two may coincide or they may not - to find out which we would have to go outside testimony. And in your summary you write '(that isn't mis- or disinformation)' , which is again to say that we only accept such knowledge as provisional, depending on something else.
Testimony is epistemologically problematic because people can knowingly or unknowingly tell the untruth; that is, they can lie or just be wrong.
When "testimony" is defined as "(intentional) communication of information", this means that I cannot acquire knowledge through testimony unless the communicated information is veridical (true/truthful)
I know that the word "information" is often used in such a way that it merely means "syntactically well-formed and semantically meaningful data". (See Semantic Conceptions of Information
!) Information thus defined needn't be true (veridical/correct/accurate) and can be mis- or disinfirmation.
"I like to think of information, at least as a first approximation, as what is left from knowledge when you subtract justification, truth, belief, and any other ingredients such as reliability that relate to justification. Information is, as it were, a mere 'idle thought'. Oh, one other thing, I want to subtract the thinker. Anyone who has searched for information on the Web does not have to have this concept drummed home. So much of what we find on the Web has no truth or justification, and one would have to be a fool to believe it, and it is not even clear that anyone would want to claim credit for thinking it. It is something like a Fregean 'thought', i.e., the 'content' of a belief that is equally shared by a doubt, a concern, a wish, etc. It might be helpful to say that it is what philosophers call a 'proposition', but that term itself would need explanation."
(Dunn, Michael J. "Information in Computer Science." In Philosophy of Information
, edited by Pieter Adriaans and Johan van Benthem, 581-608. Amsterdam: Elsevier, 2008. p. 581)
Information qua mere semantic content is independent of truth, with false information being information all the same. But others reject this truth-independent concept of information:
"What information a signal carries is what it is capable of 'telling' us, telling us truly, about another state of affairs. Roughly speaking, information is that commodity capable of yielding knowledge, and what information a signal carries is what we can learn from it. If everything I say to you is false, then I have given you no information."
"A state of affairs contains information about X to just that extent to which a suitably placed observer could learn something about X by consulting it. This, I suggest, is the very same sense in which we speak of books, newspapers, and authorities as containing, or having, information about a particular topic, and I shall refer to it as the nuclear sense of the term 'information'. In this sense of the term, false information and mis-information are not kinds of information—any more than decoy ducks and rubber ducks are kinds of ducks."
(Dretske, Fred I. Knowledge and the Flow of Information.
Cambridge, MA: MIT Press, 1981.)
Anyway, it is clear that testimony isn't a source of knowledge
unless it is the intentional communication of veridical
information. Here is the epistemic link between testimony and knowledge.
Of course, now the epistemological problem is how to find out whether someone telling me that p is in fact telling the truth, and whether I am justified in believing that p (solely) on the basis of being told that p by that person. Asking the person "Is what you say really true?"
is not very helpful, since a liar would certainly reply "Yes!"
. So what matters here is how trustworthy
the witness is. For example, ceteris paribus
, expert testimony is more trustworthy than nonexpert testimony (on the same subject matter).
and trustworthiness play a central and crucial role in the justification of testimony-based beliefs.
"Since we are in great need of information from others, we will not be so demanding that in order to avoid error, we refuse to take any risks of misinformation to gain valuable truths. Gelfert (2006) presents Kant as arguing that we have a presumptive (imperfect) duty not to distrust others and a duty of fidelity to trust the word of others because a stance of incredulity is an active suspicion of others and imposes a higher standard than is socially, conversationally, or epistemically appropriate.
An epistemological problem enters, however, if our ground for coming to these beliefs is only the speaker’s word, since that seems a very weak basis. What reason, if any, is there for a hearer to just take the speaker’s word, given that the speaker is capable of lies, deception, error, and poor, ambiguous, or misleading expression? For the hearer to trust the speaker’s word is for the hearer to ascribe authority to the speaker. Within the limits of presumed competence, the hearer ascribes to the speaker justification or warrant or knowledge for what she asserts. The hearer takes the speaker to be in a better position to settle the matter easily and transmit the relevant information, and so seeks the speaker’s testimony (Gibbard 1990; Brandom 1994; Faulkner 2007; Keren 2007). Does the hearer have good reason to ascribe that authority? In what follows, this is referred to as the Vulnerability Problem."
-- Updated November 3rd, 2017, 10:30 am to add the following --
Physics isn't the only natural science, let alone the only empirical science, so scientific knowledge is more than physical knowledge; and in "concrete reality" I use "concrete" in the sense of "physical or mental" (inclusive "or", which doesn't exclude the mental and sociocultural forms thereof from being part of the physical).
Do you consider any empirical natural science to have results which contradict physics? Or is it just that chemistry & biology offer shortcuts that trying to tackle via physics is too laborious.
In my understanding, natural science = physical science = physics + chemistry + biology. That is, I regard chemistry as chemophysics
and biology as biophysics
, such that these sciences cannot contradict basic physics and its laws. I do so because I think the ontology of chemistry and the ontology of biology are reducible to the ontology of basic physics. Chemical entities and biological ones are
physical systems. There are no hyperphysical chemical or biological entities such as an élan vital
, a nonphysical life-force. In contemporary biology, vitalism is as dead as the dodo.
Note that this ontological
reductionism is different from and independent of ideological or theoretical
reductionism, the view that all scientific concepts/predicates and theories are translatable into and replaceable by the concepts/predicates and theories of physics. Chemistry and biology are conceptually and theoretically autonomous sciences, but they are not ontologically autonomous, in the sense that their respective ontologies don't contain any hyperphysical, physically irreducible entities.