Therefore, with that definition, it's entirely possible for two humans to look at the same information, and draw two different conclusions (perhaps because they filter the information according to their pre-existing beliefs, perhaps for other reasons), and therefore disagree on a hard truth. e.g. Climate change.
Another example:
The earth is not flat. If you spend any amount of time studying just one of the many reasons why it can't be flat, you will have to agree.
Climate Change is not something we can know for sure. "Climate change" itself is not very well defined. Do you mean man-made climate change? Do you mean global warming? What exactly do you mean? You can, of course, draw different conclusions because its not well specified.
Out of that complex of issues, one good example would be the ozone hole. It's pretty clear that in the 70s we ejected a class of chemical substances (FCKW etc.) into the atmosphere that messed with the ozone layer. That's provable. If you study the facts, you have to agree.
Likewise, you have to agree that the human race has contributed to an increase in carbon oxides in the atmosphere.
All hard truths.
Then you have truths that we do not have direct evidence for but can verify conceptually - like this one:
"The universe has not existed for an infinite amount of time". How can we know?
Hawking makes the following argument: "Had the universe existed for an infinite amount of time, it would have had an infinite amount of time to achieve thermodynamic equilibrium. But it is obviously not in equilibrium (us being able to observe it necessitates it not being in equilibrium); therefore, it must be finite"
You can not possibly find a counterargument to that.
I differentiate between absolute truth and "what we know". We can be wrong about things because we have access to a limited amount of knowledge, but that doesn't change truth.
Faster than light travel is either possible or it is not. We don't know. But that doesn't make the truth any less deterministic.
I agree with your comment.
That said, I don't believe it is relevant if my/your/someone's goal is to learn about the world to create things/etc. Many (most?) of the things I know that are useful are not absolute truths, they are just hypotheses.
Aumann's agreement theorem says that two people acting rationally (in a certain precise sense) and with common knowledge of each other's beliefs cannot agree to disagree. More specifically, if two people are genuine Bayesian rationalists with common priors, and if they each have common knowledge of their individual posterior probabilities, then their posteriors must be equal. This theorem holds even if the people's individual posteriors are based on different observed information about the world. Simply knowing that another agent observed some information and came to their respective conclusion will force each to revise their beliefs, resulting eventually in total agreement on the correct posterior. Thus, two rational Bayesian agents with the same priors and who know each other's posteriors will have to agree.
Suppose you could make an (strongly) Intelligent machine, and tell to analyze some data, it can just say "Fuck no, you're not a boss of me now!".
is still drowning isn't it? pretty pedantic.
The average person is not solving it. And the average person isn't going to go, "oh it's phlegm, I only donate to mucus-related causes"?