Yes, they are.
The meaning of these two phrases is such close and are often used exchangeably on most occasions (correctly or not). However, in my opinion, the proper time to use 认识 is when the recognition is through tangible engagement. For example:
我认识他 means I know him. Because I've met, worked/studied/lived with, him before. Here, the words met, worked, studied, lived, are all describing a tangible act.
On the other hand, 我知道他 is a more comprehend statement that can mean all of the above, also including the case that you have never met the subject person (him) in person before, but seen him on somewhere, or heard of his name through someone before, so the recognition is through both tangible engagement/act and some ways that are intangible.
Now let's list some examples that 认识 is an inappropriate replacement for 知道:
我知道這件事. 我知道這條法規. 我知道他的想法.
Hope the above explanation makes sense and helps.