Continuing with my series on ways to evaluate arguments (premises, implications, assumptions, etc), the following post will discuss four more ways.
(1) Contravened by scientific findings
Another way to assess a premise is to show that it conflicts with well-established empirical facts.
Example: The claim that all of humanity has two, literal, physical ancestors prima facie conflicts with various pieces of genetic evidence.
(2) Entails something contradictory, unpalatable, false, absurd, or entails something conflicting with the arguer’s other beliefs and/or with the very argument in question. Perhaps the premises, when applied to some other aspect of the world, imply something that would undermine or rebut the arguer’s position.
Example: It can be argued that the various “causal principles” to which a number of cosmological arguments advert imply the absence of free will. But this conflicts with a variety of common theistic tenets.
Example: The conjunction of God’s essential moral perfection, creative role in the evolutionary process, and morally significant suffering of animals can be argued to entail a contradiction: that God both (a) does no evil, and (b) does evil.
These two examples above will be explored in tremendous depth in future posts of this blog, so do not get too caught up in the details. For now, I do not claim that the two examples are cogent (nor do I claim at present that they are not). They simply illustrate one way to evaluate and assess arguments.
(3) Unjustified/unwarranted/baseless assertion, along with any underlying assumptions that are implausible, underdeveloped, unsubstantiated, or controversial
Example: Empathy is why things are moral or immoral.
This is a baseless assertion and does not justify why X evoking humans’ sense of empathy necessarily implies X’s being immoral.
It could easily be the case that we evolved differently in order to have different things evoke our empathy — which arguably shows that empathy is not necessarily directed toward moral truth.
Example: Evolution is the reason there are objective moral values.
This is an unsubstantiated assertion as to why evolution functions as a truth-maker for moral propositions. It is entirely unwarranted, as of yet, to claim that evolution provides an ontological foundation for moral statements (i.e. that evolution (or certain facts pertaining to evolution) functions as the truth-maker for moral claims). Just because evolution favored X, it does not follow that X is moral.
Example: You haven’t even died yet, so you cannot know what heaven or hell are like or if they even exist.
This contains an underlying assumption that direct experience is the only means by which one could gain knowledge of this sort, which is a problematic and unjustified assumption. If theism is true, it could easily be the case that some miraculous event led God, an angel, or a saint to reveal (some of) the conditions of heaven and/or hell.
(4) The thing being argued for, such as a criteria, refutes itself. It is said to be self-refuting, self-defeating, or self-abasing.
Scientism, roughly, is the position that in order for an assertion to be true, it must be backed by empirical evidence. Naturally, this position rules out most philosophical arguments and aims to justify a form of skepticism about everything except science.
This position, however, is also logically inconsistent and demonstrably false. First and foremost, it is self-defeating. If, for something to be true, it must be empirically justified, then scientism must be empirically justified before anyone can accept it as true. However, there is no conceivable empirical justification for scientism. Physical evidence cannot show that physical evidence is the only valid form of evidence. As scientism cannot meet its own truth burden (i.e. it cannot be proven true according to the metric it says is required for something to be true), it is self-defeating and therefore false.
Second, all empirical tests are dependent upon logic. Empirical tests presuppose and therefore depend on logical principles such as the law of non-contradiction, and empirical evidence must be explained within a logical structure in order to have any impact or coherence. Thus, because empirical evidence partly derives its justificatory power from logic, logic carries at least as much justificatory power as empirical evidence does.
It is also worth noting, of course, that scientism fails to accommodate a variety of assumptions inherent to (but not justifiable by) the process of scientific inquiry.
Here is a second example: You ask me to disprove God’s existence, but that’s impossible, since you cannot prove a negative.
This is demonstrably false and self-defeating. For, if one could prove that you cannot prove a negative, you would have thereby proven a negative. You would have proven that it is not the case that a negative can be proven. Thus, if one could prove that very statement, one would have demonstrated its falsity, and thus it is self-defeating.
But, more fundamentally, you can prove a negative for independent reasons. There is an entire law of logic dedicated to proving negatives (the law of contradiction), which states that it is not the case that anything can be both A and ~A in the same respect at the same time. Thus, we can easily prove that it is not the case that, say, there exists a square circle. For that would amount to something simultaneously being a square and not a square, which is impossible.
So, it is manifestly false to suppose that a negative cannot be proven. And do you know what we’ve just done? We have proven that it is not the case that you cannot prove a negative… meaning we have just proved another negative!