My scales has been accurate for the past year. I weigh something today using my scales and it says that it weighs 1kg. Should I assume that the measurement is accurate? If so, why?
Here is the explanation for the question.
It seems to me that when we have two mutually exclusive options and we wish to decide which to assume is true for a practical purpose, we should gather evidence for each side (and gather evidence against each side if possible), and we should assume that the option with the most evidence in favour of it overall is the most reasonable one to assume true for our practical purpose.
In the case above, it seems to me that there is no evidence in favour of each side that the other side cannot explain:
It's possible that my scales gave me the accurate result, but its accurate performance in the past doesn't seem to provide evidence towards this, since it's possible that at some point it will malfunction.
It's also possible that my scales has finally malfunctioned, but there is clearly no evidence in favour of this whatsoever.
If my reasoning is correct, there is no reason to accept either option more than the other since there is no evidence in favour of any side. If so, which option should I choose? It seems intuitively clear to me that I should assume that my scales has not malfunctioned but I cannot explain why this should be true.
This question also applies to many results established by the scientific method: e.g. if we have 1000 observations made by instruments of a given phenomenon, it seems to me that we could simply claim that the instruments malfunctioned, as above.
It seems to me that probability might contain the answer, but I cannot see how.
Thank you for your help.