Given a certain piece of evidence, what should one believe? Given a certain moral proposition, should one think it is right or wrong?

What is the fundamental difference between these oughts? Something about the epistemic norm/standard seems more grounded, fleshed out, and reasoned as opposed to say moral standards. And yet, if Hume is correct in there being no way to get an ought from an is, is this intuition mistaken?

For example, suppose one comes across a crime scene. A person has been murdered. It has been found that John’s fingerprints were on the gun that killed him. It has also been found that there was a message history of John saying that he would kill the victim. His DNA has been found on the victim as well.

Now, given this, what should you believe? Even if one asserts an axiom that states the goal should be to believe what is true, what reasons could one have to show that I should now believe that John is the murderer? What “degree of probability” should one attach to this belief, if that applies here? Both of these questions seem unanswerable because of the is-ought problem.

Or to rephrase, how would one argue against someone who thinks there is not enough evidence to suggest John is the murderer? That person could, for example, say that one should believe in nothing unless one can’t doubt it. And since John being the murderer can be doubted, one shouldn’t believe it. It seems that there’s no way to argue against this without hinging upon oughts that can’t be justified through any “is” statements.

And yet, intuitively, believing that John is a murderer here seems more well reasoned and objective than a proposition like “lying is bad”. Does this imply that our intuitions are wrong and that our beliefs ultimately are a matter of faith rather than some well reasoned rational standard?


3 Answers 3


Why believe anything at all?

Maybe, in order to act consciously we need to believe, as we would need to choose acting over not acting as being preferable.

In this way, perhaps we believe because embeded in our biology is the "mandate" to avoid not acting, ( which leads to starvation,dehydration etc... modes of being so suffering fueled it seems as close to a objective moral "bad" as we humans can get)

So, if we believe because believing leads to actions which are ingrained in us which help us avoid states of being which are so painful, their avoidance seems self evident.

The next question is what should we believe?

Q: Should the reasoning for why we believe anything at all, be the same reasoning for adopting new beliefs?

If Yes, then we should adopt new beliefs if they avoid unbearable suffering.

If the root of suffering is relative, and people suffer for contradictory reasons, then their beliefs would be subjective as well.

If the root of suffering is the same, and the cure is the same ( as is the case in many theological traditions, Sin, Attacthment, Desire, Divine Punishment, etc) then their would be an objective way to adopt beliefs.

If no, then depending on why we adopt beliefs, will determine if the believs themselves have a subjective, or objective basis.

Note: I believe that different endeavors lend themselves to different reasons for belief, in a very pragmatic way.

A Judge should aquire beliefs for the persuit of Justice, a scientist for the pursuit of truth, a artist for the pursuit of beauty...

I believe that every human is a plurality of the above positions, and so not only is what one should believe not objective, it isnt even objective within ones own mind.


According to many (Hobbes, Rousseau, Nietzsche, Schopenhauer, etc.) survival is our final goal.

Ergo, what you should "think is right or wrong" is what is logically consistent with such final goal (e.g. killing is bad because it risks survival).

Same if you have another final goal (e.g. if my final goal is to get rid of bad people, then, killing is good).

As you see, there are no objective standards, all are subjective. My personal final goal seems to be survival, so I, in that sense, I think that what Nietzsche states "is right".

  • This just translates to “According to these people, one ought to do X”. But why? Survival is certainly a primal instinct but one could simply just not want to live. Sep 4 at 11:04
  • Not at all. I have my own goals, I am as subjective as any, so I have my own beliefs, I act by my own will. Survival is not only an instinct, but also a rational decision (normally instincts are logically coherent with reason, and when they aren't, you are inconsistent, which only brings self-destruction). If you don't want to live, that' s FINE as a final goal, so you can believe that "drinking poison is right", which would be "right" in your case and "wrong" in mine.
    – RodolfoAP
    Sep 4 at 11:07
  • It seems that you’re admitting the standards are subjective then. So the answer to the main question would be a no from you? Sep 4 at 11:11
  • @thinkingman correct, you can read it in the answer: "As you see, there are no objective standards, all are subjective".
    – RodolfoAP
    Sep 4 at 13:31
  • I see it now, after your edit :) Sep 4 at 13:32

Descarte's radical skepticism "cogito ergo sum" (or was it "je pense, donc je suis"?) shows is that we can't be sure of anything other than our own existence. There are arguments that we can't even be sure of that. How can we have objective standards if we have no certain knowledge of anything (other than tautologies or logical/definitional contradictions), only beliefs?

Nothing can be established beyond unreasonable doubt. There may not be completely objective standards, but there are standards that can be based on reasoning that can be shown to be optimal under what most would consider reasonable assumptions. For example, objectivist Bayesian probability. Other forms of reasoning can be justified, it depends on what is important to you.

Fortunately we don't need completely objective standards to work out what we should reasonably believe. However as there is no objective standard for subjective standards either different people may disagree, the best you can do is to explain/justify/quantify your reasoning.

how would one argue against someone who thinks there is not enough evidence to suggest John is the murderer?

You could quantify your prior belief and give justification, you could explain how the evidence affects your prior belief (i.e. the likelihood of the evidence under the hypotheses that John is the murderer and it's negation) and calculate your posterior belief. You could then have a discussion as to whether the prior was well justified and whether the likelihood was appropriate. At least then you would have explicitly stated your assumptions and your reasoning. Of course if you want to win the case, rather than determine the truth, that might be a bug rather than a feature.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .