بررسی راه‌حل گرکو برای «مسئلۀ زباله» در معرفت‌شناسی گواهی

Posing the issue of fallacies, Aristotle tried to keep safe the discursive reason-one of the sources of knowledge-from likely errors. Likewise, John Greco wants, in fact, to determine the reliable framework of testimony-another source of knowledge-by introducing the garbage problem. To solve the problem, he tries to consider the garbage problem as a generality problem. In this way, the relevant parameters-which are determined by the practical concerns/tasks that form the epistemic community -warrant reliability by narrowing the transmission channels. We will recognize some deficiencies in his view taking an analytical and critical approach and a comprehensive look at his epistemology of testimony in general. Therefore, we indicate that a better formulation of the problem can be offered. We cannot ignore the two following difficulties though the difficulty of letting luck into knowledge and the difficulty of a partly person-oriented solution being somehow resolvable. First, Greco does not explain how practical concerns lead us to the right results. Second, it is not that the practical tasks and the relevant parameters are always known.
 
 
 
Introduction
After theorizing in this domain for over ten years, Greco wrote a comprehensive book on the epistemology of testimony in 2020, The Transmission of Knowledge. In this book, he puts forward a new theory for solving many problems in literature; although he admits that he doesn’t dig into details too much. He uses the very theory to solve a problem that he, apparently, poses for the first time and calls it “the garbage problem.” It should be mentioned that he presents the problem and its solution in 2018 in the article “Transmitting faith (and garbage)” and in 2019 in the article “The transmission of knowledge and garbage”, but in this book, he puts it in a coherent system along with other problems.
Knowledge is often transmitted alongside garbage. For example, parents transmit prejudice to their children in addition to the huge amount of information they give them. The problem is to explain how knowledge is transmitted along with garbage. Even if the hearer has good evidence for the competence and sincerity of the speaker, it is not usually so easy to sift out the knowledge from the garbage.
Greco’s solution for the garbage problem
Greco’s general strategy is to treat the garbage problem as a generality problem. Just as in other sources of justification and knowledge, like perception, the relevant parameters warrant the reliability of the process/faculty; in testimony, too, the relevant parameters bring reliability by narrowing the transmission channels and therefore preventing concomitant garbage. Here, the relevant parameters are determined by practical tasks/concerns–the concerns that constitute the epistemic community. Epistemic communities have two kinds of informational needs: acquiring the information relevant to their practical tasks and distributing that information to the people who need it. Norms or standards will guarantee the quality of this information for a well-functioning community. These are the parameters regarding the conditions and scope of adequate perception/testimony/etc. Different epistemic communities have different norms or standards depending on the tasks at hand.
Now we can easily see how the garbage problem is solved. Suppose that you go to a skillful doctor to treat your medical problem. During the meeting, the doctor talks nonsense about politics and brings misconceptions to support his views. While the doctor is completely reliable in the first scope, he says garbage in the second scope. But considering that the purpose of going to the doctor is to get information about the condition of the disease, his garbage-talking is not important. That is, in this practical task, the reliable transmission channel between you and him in the community that has given him license is only the scope of medical information.
Greco comes to an end by addressing a problem. The problem is that sometimes the relevant practical concerns or relevant parameters are not known. Greco’s answer is the same as Heller’s to the problem of generality: context fixes the relevant parameters, in a very complex way that cannot be easily codified in rules. It is not reasonable to try to find a rule that can determine the relevant parameters in each case. This is because, on the one hand, we don’t have access to the multitude of contextual features that play a role in determining the parameters, and, on the other hand, since we are adept enough in recognizing the reliability of a process for practical purposes, we don’t need such a rule.
Objections
Greco tries to solve the garbage problem with an externalist approach. Hence, we will move in the same framework in our examination of his view and avoid criticizing him from an internalist perspective.

The first objection concerns Greco’s formulation of the problem. He considers his problem to be the explanation of how knowledge is transmitted right alongside garbage. But the answer he gives only specifies the transmission of knowledge and its correct scope. In other words, the problem and its answer are not consistent. The problem is how knowledge and garbage are transmitted together and side by side, not to explain the difference between the transmission of knowledge and the transmission of garbage. But the answer he puts forward determines the exact scope of knowledge transmission–that is, successful transmission channels versus unsuccessful transmission channels–by practical tasks constituting the epistemic community. Therefore, it is better to formulate the problem as follows: Based on other theories of knowledge transmission, knowledge is transmitted right alongside garbage, without making a distinction between them, and this is epistemically bad. How can we avoid it? In other words, in what ways can we prevent the garbage from entering our realm of knowledge?
Based on this solution, we determine the relevant parameters guaranteeing reliability with due attention to the practical tasks. Now the question is: how do we know that paying attention to practical tasks results in knowledge or justified belief?
We saw that Greco tried to answer with a kind of contextualism and relying on our adeptness, the objection that says that practical concerns or relevant parameters are not known. But his answer is not convincing, because if the context and our adeptness were enough to recognize the relevant parameters or degree of generality, basically there would be no generality problem or garbage problem.
As it seems, Greco’s solution is rather individualistic. This is despite the fact that social and legal dimensions are very important in the transmission of knowledge, especially when we go beyond ordinary, unimportant, and infertile-for-lying matters and reach unfamiliar, important, and fertile-for-lying matters such as scientific or medical propositions.
This solution still does not prevent luck. And knowledge is not luck for anything; otherwise, every true belief would be knowledge.

Conclusion
Greco solves the garbage problem using his information economy framework, with which he provides solutions to many problems in the epistemology of testimony. Though he puts his view in a coherent system adroitly, it is not a successful solution, as the preceding objections show. Because the garbage problem and the generality problem have a similar destiny, the former can be seen as a great challenge to the externalist theories of knowledge. In this way, the need for the internalist aspect of knowledge is felt more than before.