If you see any mistakes in the following please let me know. This is for a paper. We often say that energy is abstract but it is certainly less abstract than say velocity or pressure by virtue of the fact that it seems to cause particles or bodies to displace other bodies. Undoubtedly particles move and they also have an ability to displace other particles or bodies. This ability to displace bodies can be quantified in terms of energy. Whatever it is that causes bodies to move, then energy is the best candidate. We certainly wouldn't say that velocity causes bodies to move or pressure but ultimately we have to give a name to that cause that causes bodies to move and energy it seems is the best name for that cause.