In philosophy, the word argument offers a completely different meaning than the one that we commonly use in our daily speech. Contrary to its everyday nuance of squabbles, disputes and fights—arguments in philosophy are viewed as a set of statements in which premises (reasons) are given for the acceptance of a claim or a conclusion.
An argument is only accepted as true and rational when sufficient evidence or proof is offered for its acceptance under proper logical patterns. But which one of the conflicting parties in an argument has to offer this evidence? Or in other words, who will bear the “burden of proof” in an argument? This is of paramount importance as it can cause confusion within the audience in a debate and hence lead to their support of a faulty position.
Here, I want to involve you in a thinking spree about role of evidence in a claim and whether the proponent or the opponent carries the burden of proof for their respective position. It is not just an interesting theoretical question. It also has very practical real-life implications.
Consider the following example of Bibagr’s argument:
Bibagr: “Have you seen Shantol lately? She has stopped wearing her sarig (headcloth). She must be a slut.”
Friend: “How can you say that?”
Bibagr: “Can you prove she isn’t? No, right? She must be a slut then.”
Here, Bibagr asserts a claim against Shantol being a slut (though there is nothing morally wrong with not wearing a sarig), but instead of offering any evidence to support his claim, he shifts the liability of proof to his friend and ask him to prove it wrong.
Bibagr is guilty here of violating the rational pathway of reasoning and has committed the sin of a fallacy (error in logic).
When someone asserts a claim or tries to establish that something is the case, then that person is said to have made a positive claim. By virtue of philosophical inquiry and critical thinking, the rule of thumb would be that whoever makes a positive claim has the onus of proof for that claim. In the above example, Bibagr makes a positive claim about Shantol, hence Bibagr is required to support the truth of his claim with evidence. His friend is under no obligation to accept his claim or prove otherwise: that Shantol isn’t a slut.
Similarly, one of the most popular example in this case would be the following argument between a theist and an atheist:
Theist: “God exists! He is omnipotent and omnipresent; He listens to our prayers and helps us all in mysterious ways. God is great! All praises are for God!”
Atheist: “What evidence do you have to prove the existence of your Almighty God? And if your God is so Almighty then why do humans carry out all of his actions on the earth?”
Theist: “God exists! You fool! Everyone believes in God. Science has been unable to prove that He doesn’t exists. So, God must exist and you should start believing in Him too!”
The theist makes a positive claim by asserting the existence of a supernatural deity. The onus of proof obviously rests on the theist shoulder. Although this is a special case of fallacy known as Appeal to Ignorance (a reasoning error where something is assumed to be true because no one can prove otherwise) but again, the atheist is under no obligation at all to accept the theist’s claim or try to disprove the existence of God. He is entitled to reject the theist’s argument until sufficient evidence is given out by the theist for his position, making it worthy to be challenged in a philosophical arena.
But can the “burden of proof” ever shift to the other party?
From a logical and critical perspective, the burden of proof lies on the party that makes a positive claim. When someone who made a positive claim tries to push the burden of proof against their opponents, such as the argument between Bibagr and his friend, and between the theist and the atheist, they commit a logical fallacy. Though there is no harm in offering evidence to counter a positive claim, it gives unnecessary attention to obviously ridiculous ideas such as terming the moon landing as fake moon landing, offering the “flat earth argument” and other related conspiracy theories and superstitions.
One thing should be strictly kept in mind that although this order is mostly true in philosophy, in the discipline of Law the burden of proof can shift to the disputing party under special circumstances called “Reverse Onus”, where a defendant is asked to disprove a positive claim.
Vaughn, Lewis. Philosophy Here and Now: Powerful Ideas in Everyday Life. 2nd ed., Oxford University Press, 2016.