... This comparison is silly. Gravity is a phenomenon that happens outside of human perception. It would happen without lifeforms. Love and ethics are concepts that cannot happen without them being perceived by an intelligence.
I'm sorry the example I offered doesn't work for you.
The difference you point out is an important one. Indeed, it's why I believe we need religion as well as science. Physical phenomena such as gravity are real, and can be studied dispassionately because they can be observed outside our lives. But metaphysical phenomena -- while equally real -- can only be perceived and studied in connection with how they manifest in the way we live our lives.
I do not believe that love, respect, compassion, cooperation, honesty and justice are simply created concepts. I believe that these are real phenomena -- as real as gravity. As such, I believe they are worth studying and understanding (and aspiring to).
The general approach to studying metaphysical phenomena should be the same as for studying physical phenomena -- careful and honest observation of these phenomena as they manifest themselves in the world around us. But with things such as gravity, we are able to observe the effects not only on ourselves but also on other phsyical objects around us. This is helpful in studying and comprehending such phenomena dispassionately. With things such as love, respect, compassion, cooperation, honesty, and other metaphysical phenomena, we are only able to observe the phenomena as they manifest in our lives and the lives of others around us. Our lives are our laboratories.
In the laboratory of my life, through the limited experiments I am able to carry out and the limited observations I am able to make, I come to certain beliefs. In the laboratory of your life, through the limited experiments you are able to carry out and the limited observations you are able to make, you also come to certain beliefs. If things such as love are (as I believe) real, rather than simply invented concepts, then over time -- as we learn how to conduct meaningful inquiries, as we find ways to observe carefully, and as we find ways to record and share what we have learned -- over time those engaged in such inquiries should find their beliefs converging and should find themselves reaching similar conclusions on specific matters.
The emergence over time of such convergence is how we recognize progress in science. It is also how we recognize progress in religion. If no such convergence ever occurs -- if, as century after century passes, religous belief remains as arbitrary as astrological belief -- that will be a good indication that religion is as baseless as astrology. From my perspective, such convergence has been occurring -- slowly, over centuries, but occurring nonetheless.
Dogma said that the ownership of one person by another is justified; inquiry led to belief it is not. Today there is general consensus, regardless of religious belief (or lack of it) which says ownership of one person by another is not right. That indicates to me this is not simply an arbitrary construct but an actual truth.
Dogma said that women were not moral equals of men; inquiry led to belief that they are. Today there is general consensus that women and men are moral equals. This indicates to me this is not simply an arbitrary construct but an actual truth.
Today dogma says that homosexuality is sinful; inquiry is leading to belief that love and fidelity are good things regardless of sexual orientation. I believe that within 100 years, hopefully much less, there will be general consensus on this, and people will look back on arguments over gay marriage much as we now look back on arguments over slavery. And if so, that will also indicate to me that there is a truth here, and not simply an arbitrary construct.
These are important question, questions which I believe we as a society can and should be wrestling with -- questions as important, and as real, as questions of how plants grow, how life evolved, how stars are born, or how wood burns.