Introduction: This is a tweet from a prominent twitter poster named, Ryan Knight (@proudsocialist). He has additional presence on social media. Knight is usually considered a far left, progressive.
Key Facts: N/A.
Text: “Billionaires would not exist without exploiting the labor of the working class and the natural resources of the planet. I don’t believe the people or the planet should be exploited. Therefore, I don’t believe billionaires or the decrepit capitalist system that made them should exist.”
Comments: the biggest concern I have with an argument like this is just the level of abstraction. The terms are just too big for me, the categories too sweeping to make judgements about an argument like this with any degree of confidence. I mainly post it here, because it’s kind of an interesting example of Modus Tollens.
 Billionaires would not exist without exploiting the labor of the working class and the natural resources of the planet.
 I don’t believe the people or the planet should be exploited.
 I don’t believe billionaires or the decrepit capitalist system that made them should exist.”
Discussion: This argument raises the following themes; Micro-Reasoning, Modus Tollens, Moral Reasoning, Qualification.
Micro-Reasoning: It’s a tweet, so the argument is brief. This is compounded by the sweeping nature of the claims made about complex economic arrangements. In a larger and more complex argument, perhaps Knight could define his terms and develop a substantial case for his position. Here, we are left with summary judgements about his own beliefs. This leaves readers to do but agree or disagree on the basis of little other than their own ideological assumptions about the nature of capitalism.
Modus Tollens: The first sentence (statement 1) could be loosely translated as a conditional statement (“If Billionaires exist, then “without exploiting the labor of the working class and the natural resources of the planet.” The second premise then denies the consequent, and the conclusion denies the antecedent (with additional commentary on the “decrepit capitalist system.” That commentary could be treated as a distinct claim in its own right (one which is not contained in the premise). It could also be treated as a rhetoric flourish, leaving us with a Modus Tollens.
Moral Reasoning: It’s difficult to say on what basis Knight makes judgements about what ‘should’ or ‘should’ not exist. That would always be a tricky question, but it’s a little more difficult in the sort of arguments you get on twitter. Here at least, the question remains unanswered. Those familiar with Knight’s account may have a better sense for how to answer that question.
Qualification: One important qualifier for those argument lies in the fact that Knight isn’t necessarily talking about the real world at all. Both statements 2 and 3 are explicitly about what he believes. If we take him literally this is just a statement about his belief states. Under many circumstances we might ignore the qualifier and treat these statements as descriptions of the real world after all, but without more information about how Knight wishes to define the key terms and build up supportive arguments, it may be better to just accept the narrower significance of these statements as the one intended here.
Evaluation: Treating the argument as Modus Tollens means of course that it is deductively valid, which means the truth of Knight’s premises are the only substantive questions at issue. Were I to evaluate the truth of his premises, I would want to raise some questions about how he means to define the terms ‘capitalist,’ ‘workers,’ and ‘exploit,’ at the very least. I would also want to know how he arrives at his judgements about what ought to be. Adopting the narrowest interpretation of statement 2 makes things a bit simpler, but that doesn’t help much. I would accept Knight’s word on his own beliefs, but that still leaves a lot of questions about key terms in statement number 1. Perhaps, I could imagine a version of the statement which would, but it’s probably stretching the principle of charity a bit far to adopt this interpretation in the face of so many questions. I’m inclined to regard the argument as unsound due to the questionable truth of its premise. A more detailed version of the argument could well change that evaluation.
Final Thoughts: Really, I was just amused to find Modus Tollens on twitter.