Science is falsifiable. Or at least, this is what I (like many Americans) learned in many of my high school and college science classes. Clearly, the idea has appeal among scientists and non-scientists alike:
![Tweet by Dr. Michio Kaku stating, “Can you prove the existence of God. Probably not. Science is based on evidence which is testable, reproducible, and falsifiable. So God is outside the usual boundary of science. Also, it is impossible to disprove a negative, so you cannot disprove the existence of God, either.”](https://blogs.iu.edu/sciu/files/2021/06/Kaku_tweet.jpg)
![Tweet by Dinesh D’Souza stating, “Karl Popper taught us that a valid scientific theory is narrowly drawn and makes specific predictions that can be empirically tested to invalidate the theory. Now ask yourself: by this standard, is “climate change” a valid scientific theory.”](https://blogs.iu.edu/sciu/files/2021/06/DineshTweet.jpg)
![Tweet by Naval stating science is independently verifiable, falsifiable, and makes risky predictions (read Popper/Deutsch). It responds to a tweet by a Mike Solana stating “is there a less scientific phrase in popular discourse than “believe science”.”](https://blogs.iu.edu/sciu/files/2021/06/Naval_Tweet.jpg)
But what exactly does “falsifiable” mean? And why is it valued by some scientists, but dismissed or even considered actively harmful by others?