Panagiotis Panagi Posted over 4 years ago What are 10 things YOU know to be true? @Vilgot Ok, I'm with you that we need to use whatever knowledge we have, take some things for granted and build on those. I'm just saying that truth is totally subjective and is only valid under specific assumptions. For example you propose that "2+2=4", which however is an idealization. In the universe round numbers do not exist. When you measure for example the voltage of a 2Volts battery you will never get 2. You can only approximate it by 2. The true voltage of the battery is unknown due to noise, disturbances, energy losses etc. So taking two batteries of 2Volts and adding them up does not mean a total voltage of 4. We only *assume* that the total voltage is approximately 4, but the "absolute true voltage" is unknown. In order to know the exact voltage you will need to measure the energy of every single electron that passes through the wires, which is impossible (quantum theory). Therefore in real world "2+2=4" does not exist, only "approximately 2 + approximately 2 is approximately 4". So I believe, math and any math equation is an idealization of a specific real world phenomenon, and bound to an error. It never describes exactly the phenomenon, which means that it is never "absolutely true". The implication of this is that the universe will never be fully described by a theory. Perhaps approximately but never absolutely. Any truth will always be subject to failure. Can I prove this? No, but Godel did.