Is it okay to do a PhD in the domain you barely know? I consider myself a Software Engineer. However, I recently accepted a PhD position in Data Science domain (i.e. which I barely know). I am slightly motivated because I believe that data can have a tremendous impact for the society. Despite of that, I still have some doubt. How do I cope with the doubt? Is it normal for every PhD student?
It's totally OK!


When it comes to PhD, enthusiasm, dedication and perseverance worth far more than prior knowledge and intelligence. 

In fact, many of the people I know started their PhD without even knowing the slightest basics of their topic, but they excelled nonetheless. 



This includes me. Since were in similar fields I suppose I could share my experience. I chose machine learning (ML) out of impulse because I was passionate about AI. I didn't even know the definition of ML when I started my PhD. Now, I'm recoding ML algorithms twisting them to my research needs. Moreover, I'm even teaching my students and colleagues to do the same. It's truly a magnificent experience.