Values are set in place. We have "no more power of inventing a new value than planting a new sun in the sky or a new primary colour in the spectrum." However, what is important is not whether or not these values exist, because it is clear that they do. What changes all the time is the significance that is placed on certain values in certain periods of time.
In an ideal world there would be one universal Moral Law... the one that God Himself grants His people in which the values are placed in order. I believe that this does exist, and that He intends for his people to follow it. But it is not followed by everyone, and that is why subjectivism has caused such controversy in our world then and now.