Although science and philosophy are are related, actually they are two far corner of a square. The common point is just curious. Both science and philosophy ask the unknown but science must be realistic meanwhile philosophy may not be. If you cannot prove something you believe it is just a tought similar as philosophy.

There are some exceptions for this. For example, Einstein postulates that nothing can pass speed of light. This can be philosophy also. There are some explanation about this issue but this is not a theory. Also there is no confliction with this postulates so we can use this postulates describing somethin. For some calculations we need these kind of postulations. However, you cannot say there is no gravity without any explanation. In philosophy you can. Philosophy can be limitless,but science cannot be.