Except we have discovered and made a lot of weird elements and we know or can reasonably predict their probabilities, giving us even more empirical proof why they wouldn't form stars than the obvious bits - they shouldn't look the same as properties of materials in that respect are byproducts of other properties which themselves differ and that there is no known or suspected reason they should, from observable evidence.



"Know" is fine. I 'know' that if I hit the 'y' key on my keyboard a 'y' will appear on the screen, so if a 't' shows up, while any number of other explanations may be the real one for that particularly case, its a fair bet I just hit the neighboring key. I know that the reason I regularly capitalize the second letter of someone's name when typing is I tend to be a little slow releasing the shift key if the second letter is on the opposite half of the keyboard form the first, my shift finger releases just a moment slower then my other set of finger drops to depress that key. I "know this to be true". That doesn't mean ever case of it happening was from that, the shift key may have gotten stuck, a piece of corrosion may have slowed the signal slightly, I may have done it on purpose and forgotten why, and likely there are a fair number of occasions where one of those has happened. I also can't disprove that some freaky gnome didn't spontaneously show up to jump on the shift key. The difference in all of those is I have strong empirical evidence I lag on releasing the shift key, and that I have strong theoretical evidence that those earlier alternates, the key getting stuck, the wiring being corroded, etc can occur, I have neither for the gnome. I also, if I watch people type a lot, can build up a good database of which typos occur more frequently and why, I may build up a good group of empirical evidence and produce a good theory saying "People are 25% +/-3% more likely to accidentally capitalize the second letter of a name if the keystroke was fro the opposite piece of the board, and further, that they are 12000% percent more likely to do so if the capitalized the first letter, there is a statistically insignificant number of occasions where a second letter was accidentally capitalized where neither the first nor other letters were." Now, if this is peer-reviewed and accepted, a teacher might see lots of those in an individual students writing and say "John, you have a problem holding the shift key down" and he may say "MRs. JOhnson, I do know such thing" and the teacher has a reasonable right to roll their eyes and say "Trust me, I know you do" by ignoring an option of a bad keyboard, if the errors clearly took place on two different machines, and to ignore the Prankster Gnome Hypothesis.

This is science, this is empirical evidence, and 'know' is justified, it's never 100% but nothing is or can be, so its use is as fair as in any case. I can explain in detail how we can say these things with reasonable certainty, to the point that I feel entirely confident using "I know most stars are composed primarily of hydrogen and secondarily of helium' with the same confidence, greater confidence really, then I can say that cars run on gasoline, I can not after all, personally visually detect the difference between a kerosene or electric car at a glance, a mechanic or engineer likely could, and I would accept their statement 'know' even though it is entirely possible someone deliberately obscured whatever visual or audio markings that might indicate otherwise, so his ability to render that comment, that 'he knows it is a electric car' is likely of less validity then my comment that 'Alpha Centauri burns hydrogen', because I have no empirical evidence that someone might or could tamper with my observations of that, whereas I can present a very reasonable explanation that a car company may wish to manufacture an electric that to passing or even moderate scrutiny appears to be a 'normal' gas guzzler, nevertheless, his use of 'know' is solid enough without additional reasons to suspect he could and would be wrong. I know there are approximately 300 million people in the US, I have certainly never counted them, I know that the capital of Delaware is Dover, I have never been there, I certainly have never looked at any charter proving it, let alone seen any personal evidence this was so. I accept it as a fact and 'know it' for the same reason I 'know' that Earth is 1 AU from the Sun and that the Sun is primarily burning hydrogen, I can prove this as rigorously as I can prove Dover is the Capital of Delaware.