Engineering is not as simple as building against gravity. There are a lot many things that "engineers" (non-software) have to take account of, even in something as mundane as laying out a road. In this example, you not only have to build the road within the area; you have to build it so that it has the right curvature so that vehicles can make the turn etc. You have to make sure that the road you're laying out has a solid base; you need to make sure that the road can withstand the natural forces of that region for whatever time it is designed to last against. So I don't understand how engineers build against gravity.
But if you're saying that engineering has to follow the laws of physics, then yes, I'm totally on board. Computer Science departments in most universities started of as branches within the mathematics department. While most of software engineering is more than simple math; it does operate on its own plane, with no regard for the laws of physics (except maybe of time :) ).
In that regards, Software Engineering seems more of an art, doesn't it? But it does have its own guidelines; which govern how good software is written.
A road is a bad example. The only reason a road is required is because of gravity.
I disagree with your hand wave of "software = art". Software is also bound by many constraints. Time (as you mentioned) is not trivial because it's the difference between useless and useful software. Memory also puts limitations in that can't be ignored.
Useful software runs on real machines bound by physics. Theoretical computer science can disregard the constraints to see what's possible, but that's CS and not SE.
Software engineering is an art in that it's more like theory building than theory using. Each project, each context is its own set of new physical laws.
But if you're saying that engineering has to follow the laws of physics, then yes, I'm totally on board. Computer Science departments in most universities started of as branches within the mathematics department. While most of software engineering is more than simple math; it does operate on its own plane, with no regard for the laws of physics (except maybe of time :) ).
In that regards, Software Engineering seems more of an art, doesn't it? But it does have its own guidelines; which govern how good software is written.