No, a belief that galaxies exist is rational given certain evidence.
Your claim about its instrumental value is simply wrong. Any knowledge is useful if it has consequences for something we wish to do, and the only way to know whether a given piece of knowledge has such consequences is to know it well.
No, a belief that galaxies exist is rational given certain evidence.
Your claim about its instrumental value is simply wrong. Any knowledge is useful if it has consequences for something we wish to do, and the only way to know whether a given piece of knowledge has such consequences is to know it well.