How to get from an is to an ought

I have an explanation of how we get from an ought to an is and it doesn't require a definition of truth.

--- Definitions ---
Science, investigating reality:
This includes any method of investigating reality, including using the equipment we got from our biology. So without science we can't do anything useful because we won't know what's happening. We would not even have sight. Comparing modern science to our understanding of reality in the dark ages is like turning on the lights in a dark room. In such a dark room we might flail our arms around, but in order to do anything useful we'd have to use our other methods of investigating our surroundings.

Morality:
What determines how we feel about a situation and thus how we will judge a situation. This flows from a number of sources: - Instinct (I think most important because it's very strong and people often can't overcome it, even if they want to) - Parents (how you are raised) - Culture (can overlap with parents) - Personal experience Without information about a situation we cannot judge it or even know it exists.

--- Conclusion ---
So on their own these components don't do anything, so we need to combine them. Because while we cannot get from an is to an ought, just by using the is, we cannot get there without the is. For morality to have any meaning we need the is. Science allows us to get closer to the is. We can then use our instincts to get from the is to the ought. If we don't use science we won't be able to get a good starting point and reach the best ought.