In science, ask why?
In life, ask why not?
In science, you’re trying to figure things out. To do so, you have to keep on asking why? to get to the root cause and full understanding. Life, on the other hand, is not logical. It’s also not fair. You need to live it with passion, not absolute reasoning, though some is highly recommended. Don’t let doubts, other people, yourself, material barriers, and any other such things stop you from doing and/or being what you want. Ask why not? if something seems to be in the way. You may find there is a good reason or reasons why you shouldn’t do something, but like how you ask why till you get to the root cause of understanding something, ask why not until you get to the absolute reason why you might not want to do something. But even then, sometimes ask one last why not? and just go for it!