As a preface to the following, these events do not, in fact, affect me in any sort of pragmatic manner. My contention is a philosophical one, and this is written in order to incite others to think about the implications of their actions to a greater degree.
Earlier this week, a friend beckoned me in saying he wanted to transfer a batch of beer into the secondary fermenter. I thought it was too early, so I told him on how to take specific gravity measurements in order to confirm fermentation had indeed finished. The next day, he informed me of the gravity readings, and I voiced concern that I didn't seem right. He went ahead and did the transfer. Today, he took another reading, and it was indicative of fermentation having not been completed. For the purposes of this writing, the details of brewing do not need to be known; just that fermentation should be complete before the brew is transferred.
Against this backdrop, I believe to have been the recipient of testimonial injustice. Testimonial injustice is the main subset of epistemic injustice which, of course, is in the realm of epistemology, the study of knowledge and how one comes to know things. Testimonial injustice is where one person is telling another something, and the hearer, due to some prejudice, denigrates the level of credibility given to the speaker. This results in a specific form of injustice where the hearer undermines the speaker, specifically in his capacity as a giver of knowledge.
After inciting my opinion, my friend essentially ignored my advice and did what he wanted. This was the incident of testimonial injustice. Without a prejudice, and to an extent the falsification of that prejudice, testimonial injustice cannot occur. The prejudice was that we started brewing together and thus have equal experience. His opinion would be as valid as mine. However, in practice experience alone is not the entirety of what ought to be considered. One might have been exposed to this earlier on, or the other may have done extensive research on the process, or whatever. In this particular case, I have done a great deal of reading and research about this subject matter and have the scientific background in chemistry and microbiology to understand the dynamics of fermentation. This is said not to elevate myself above reproach or anything of that nature, but to establish that I do possess knowledge about this.
After describing the setting and defining terms, one comes to the question "Why is this an injustice?" My position as a giver of knowledge was undermined by the discrediting of my testimony. A knower claims to possess a form of rationality which one uses to gain knowledge. In philosophy, rationality is considered an essential human value that makes us special and distinct from all other organisms. Biblically, I find evidence for this position as well. Testimonial injustice results in the undermining of one's position as a knower and consequently in a capacity - rationality - essential for human value. Even though this a very trivial matter, and thus my position as a giver of knowledge was undermined in a very small capacity, my very humanity was called into question even if only slightly. This, friends, is a grave proposition.