Well, but a creationist of course denies the "relative ages and time periods" part of the picture here.
Well, they don't, actually. Granted they reject the geologic scale of the timetable, but they certainly don't reject the idea that it
is a timetable.
If you're burying things by sedimentation, the stuff on the bottom has to be older than the stuff on the top. How do you sediment something
below another layer? It's physically impossible.
The reason that I said "relative age", and not "absolute age", is because creationists and evolutionists alike agree that the geologic column is a timetable of relative ages - this came before that, that came before the other, etc. Never mind the actual time involved.
Unless what you are measuring is, say, cupcakes, and you find that they are all composed of similar but different proportions of sugar and flour and eggs and baking powder, amazing coincidence, and then you also check the recipes by which they were made, and oh double amazing coincidence, there is the flour, the sugar, the eggs and the baking powder, and in VERY SPECIFIC QUANTITIES TOO, oh happy day.
Absolutely irrelevant example. You proposed that cladistics measures something that doesn't exist. The conclusion, when you try to measure something in three different ways and succeed three times, is that you actually measured what you claim to have measured - not that you were hoodwinked three seperate times.
You didn't propose cupcakes from one cosmic baker; you said that the cupcakes didn't exist. Or didn't have any sugar in them, let's say. If you measure these cupcakes with three different means, and you find the same amount of sugar now matter how you measure it, the proper conclusion is that you've accurately measured the sugar content of these cupcakes, not that the cupcakes are sugar-free.