It's different in the sense that the idea of dark matter allows you to make predictions. If it makes the model work, it gives you new directions to go and new t

It's different in the sense that the idea of dark matter allows you to make predictions. If it makes the model work, it gives you new directions to go and new things to discover. If the predictions don't work out, the model gets tossed. A good example of this is the aether hypothesis: https://en.wikipedia.org/wiki/Luminiferous_aether https://en.wikipedia.org/wiki/Luminiferous_aether