[1]
Grice (1957) distinguishes between a natural and an unnatural meaning. Unnatural meaning is always characterized by the speaker’s intention. The natural meaning of a sign characterizes meaning that is independent of a speaker.
[2]
I follow Jacob in relying partly on Sperber & Wilson (1986) when I talk about the Gricean account.
[3]
I will address this topic with respect to the ad hominem argument in section 5.
[4]
I will not address Gettier cases with regard to social epistemology. For the sake of this commentary, I will use the term knowledge as meaning justified true belief. Issues concerning the ad hominem fallacy will concern the justification-condition.
[5]
Lackey claims that dualism accounts only for necessary conditions for a source of knowledge.
[6]
There is further evidence in developmental psychology that speaks of very early acquisition and practice of epistemic vigilance (cf. Clément 2010; Sperber et al. 2010; Mascaro & Sperber 2009).
Another issue with regard to the positive reasons component in social epistemology is the so-called infant/child-objection. This concerns the hearer’s competence in evaluating the speaker’s reliability that small children lack, which is often construed as an argument against reductionism (Lackey 2006). For a general discussion see Lackey (2005).
[7]
As will be seen in section 5.1, there are some exceptions where personal properties are relevant.
[8]
I assume that a testimony t expresses an argument that contains the relevant proposition p.
[9]
One could of course distinguish between a testimony and an argument. Here I presuppose that a testimony is somehow a conclusion of an argument. Fricker (2007, p. 61) supports this view as follows: “One might be inclined to put a familiar picture of justification to the fore and argue that in order to gain knowledge that p from somebody telling her that p, the hearer must in some way (perhaps very swiftly, perhaps even unconsciously) rehearse an argument whose conclusion is p.”
[10]
For the purpose of this commentary I will defend a weak view of propositions. The utterance of a speaker expresses a proposition that is true if it represents a state of affairs. There is of course an asymmetry between the propositional content of an utterance and the propositional content of the speaker’s belief or thought. I agree with Jacob (1987) that it is sufficient to assume similarity between the two.
[11]
For some very interesting empirical investigations with regard to these three kinds of ad hominem arguments, see van Eemeren et al. (2000) and van Eemeren et al. (2008).
[12]
As Jacob (1987) suggests, beliefs are shared in different communities with different ideological backgrounds that are themselves constitutive of belief-formation. One could defend that the local ad hominem attack is an important tool for running a communicative society. If so, we would be using local ad hominem attacks as a form of self-deception, which would then be somehow an instance of a shared optimism bias. I will not discuss this phenomenon any further, because it is not a tool or cognitive filter that improves knowledge transmission. Hence, positive local ad hominem attacks, one could argue, have at least a propensity for being epistemically unvigilant mechanisms.
[13]
Yarp (2013) suggests that ad hominem fallacies like prejudices could be unconscious or at least not transparent to the hearer’s reasoning.
[14]
I will not consider the ethical implications of this view any further in this commentary.
[15]
Unfortunately, I cannot address in this paper which kind of mindreading is supported by this view and how it could perhaps be related to social cognition and mirror-neurons. For a general discussion see Jacob (2008, 2013).
[16]
According to Jacob (1987), a belief-ascription is not constitutive of the subject’s belief in the first place.
[17]
There are, of course, plenty of other options for different interests (cf. Sperber 2001).
[18]
The question, of course, is in which sense it is violated, in detail, and how this affects Millikan’s theory of language in general. However, these implications cannot be addressed here.