Just a quibble, but I don't think we should accept a blanket statement that biology or medicine can't predict what will happen to an individual. We do understand the mechanics about enough processes to know what will happen to certain people, such as those people with various genetic defects, such as for Huntington's disease.

Actually, the fact is that biology/medicine encompasses elements of "hard" science and "soft" science depending on the particular field or the question, so it's not so easy to give it a single label. Look at Watson and Crick, the discoverers of the structure of DNA. Using x-ray crystallography to tease out its structure is pretty "hard science".