Shih-Hao Liu
University of Miami
Knockdown arguments are arguments such that those who object to premises or supporting relations between premises and conclusions of these arguments are irrational or not able to fully understand the argument. In non-philosophical domains, there are ample of examples of knockdown arguments. However, although philosophers do argue in the tone as if they are proposing knockdown arguments for various theses as well, it seems less straightforward whether there are knockdown arguments in philosophy. While philosophers like Lewis (1983) and van Inwagen (2009) deny the existence of knockdown argument in philosophy, on the other hand, Ballantyne (2014) attempts to argue that we can obtain knockdown argument in philosophy from some established non-philosophical knockdown arguments. In this paper, I argue for a skeptical position on whether we know the philosophical arguments at hand are knockdown due to epistemic underdetermination in philosophy. First, I argue that Lewis and van Inwagen’s rejection of knockdown arguments’ existence in philosophy is untenable since the position is either self-refuting or not a position that we are rationally compelled to believe in. Second, I present Ballantyne’s strategy that attempts to establish knockdown arguments in philosophy from conclusions established by non-philosophical knockdown arguments and Keller’s criticism (2015) that arguments generated from Ballantyne’s strategy beg the question. I argue that Keller’s criticism only scratches the surface of the issue and also has the consequence of failing to retain the conviction that there are knockdown arguments outside philosophy. The deeper problem of Ballantyne’s argument, I contend, is that it is always possible for an actual (or potential being) to rationally deny one of the premises that Ballantyne deploys. Here, I appeal to literature about modal skepticism (van Inwagen 1998) to support my position. I call the phenomena as epistemic underdetermination and such a phenomena hinder philosophers from knowing which arguments are knockdown arguments. However, I argue that even if we should endorse a skeptical position in knowing knockdown arguments in philosophy. We need not be pessimistic about the future of philosophy since philosophical success and knockdown arguments in philosophy are conceptually independent.
Chair: Clement Mayambala
Time: September 13th, 14:40-15:10
Location: SR 1.003 (online)
SOPhiA 2026 