By hard truth I mean absolute truth. Facts. 2+2 = 4. If you understand all the rules that go into addition, there's no way for you to arrive at another conclusi

By hard truth I mean absolute truth. Facts. 2+2 = 4. If you understand all the rules that go into addition, there's no way for you to arrive at another conclusion. 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.