Is this an assumption made in science, taking the wider view rather than geological?

Is it necessary to understand how the Laws of Science work and is it the case that it's true?

Or can it be shown empirically that it is the case or demonstrated that we could not be where we are today if it were not so?

John

Well, when 16th century geologists went looking for evidence for the so-called "global flood" and found none, they then started asking themselves some basic questions, such as "how long does it take a sedimentary stratum to form?" Whereupon they started looking for ways to work this out empirically. When they finally did this, and the results came back, they came to the conclusion that the planet was a hell of a lot older than 6,000 years, based upon sedimentary deposition rates alone.

Plus, we have sound empirical reasons from other quarters, allowing us to conclude that the laws of physics haven't undergone any radical changes over billions of years, from several sources of empirical data. See, for example, the Oklo natural nuclear reactor (which places strict limits upon the variation of the fine-structure constant, for example), or data from distant supernovae.

Basically, the universe is characterised by extensive periods of relatively gradual change in its constituents, punctuated intermittently by local instances of more violent change, and it's been like that for a very long time.

Thanks Calilasseia

John

Calilasseia wrote:Well, when 16th century geologists went looking for evidence for the so-called "global flood" and found none, they then started asking themselves some basic questions, such as "how long does it take a sedimentary stratum to form?"

I hope that´s a typo... Hutton was an 18th century geologist (and really, geology as a discipline came around at that time).

But generally, in early geology people were split between uniformitarism and catastrophism. These positions were developed simultaneously - Hutton´s "Theory of the earth" (1795) and Cuviers "Notice sur le squelette d’une très grande espèce de quadrupède inconnue jusqu’à présent, trouvé au Paraquay, et déposé au cabinet d’histoire naturelle de Madrid" (1796) were the first works in which these positions were defended and that´s pretty much the same time.
The uniformitarists held that all geological formations were the result of slow processes that took place over a long period of time, the catastrophists argued that most of the time nothing happened at all and that singular events produced all geological formations. Arguably the catastrophists had the better evidence at the time.
The main thing uniformitarism had going for it was that it came with an active research program: actualism. To use Huttons phrase: "The present is the key to the past". To study how sedimentary layers form, one could study how they form in modern lakes, rivers, oceans or arid basins. Catastrophism had no equivalent research program and thus it went out of fashion, in particular since the actualist principle worked rather well.

In the early 80s a modest new catastrophism came around, driven by two changes: On one hand advances in mass spectronomy allowed the detection of trace elements. The Ir anomaly in Gubbio (Italy) was empirical evidence for a cosmic impact. Likewise channel structures visible of satelite photographs showed that a mass flooding had occured in north america as the glaciers retreated and the fresh water reservoir (of which the great lakes are remnants) flowed into the atlantic. On the other hand computers became powerful enough to simulate rare large scale events and thus show us what type of structure they could produce.
Current geology is neither uniformitarist nor catastrophist. It doesn´t claim that all structures come from slow processes, nor that all structures come from rare events. Rather it now has the tools to examine individual structures and find out how they formed. It´s the new research tools available to us that make this possible.

Thanks for that.

The term now seems to be applied in a much wider context and concerns the so called 'Laws of Nature'. Is that a valid concept also?

Calilasseia mentioned that there is empirical evidence for this position, is that how you see it too?

John

z8000783 wrote:Thanks for that.

The term now seems to be applied in a much wider context and concerns the so called 'Laws of Nature'. Is that a valid concept also?

Calilasseia mentioned that there is empirical evidence for this position, is that how you see it too?

John

The type of uniformitarianism discussed above is "substantive uniformitarianism" which is the idea that change is slow and gradual and evenly distributed. The 'Laws of Nature' aspect is relevant to "methodological uniformitarianism", which is the idea that the laws we discover today can be applied to the unobservable past and future. That is, if I discover a law of gravity which accounts for and predicts the falling of a rock today, then I can assume that the same laws were relevant yesterday and they will be relevant tomorrow. Importantly, the kind of periodic 'catastrophes' which contradict substantive uniformitarianism are perfectly compatible with methodological uniformitarianism as these catastrophic events are processes contained within the laws of nature.

There is no empirical evidence for methodological uniformitarianism, and I don't think there ever can be, because the process of science itself is dependent upon this axiom. As such, any evidence for or against the position must first assume that it's true, or we must devise a new method for investigating empirical claims that is not science. The reason why it's necessary to assume it is quite simple when you think about it: if we can't assume the applicability of a law or theory to the past or future, then all we can discuss are current observations. That is, my new law of gravity can explain the way this exact rock falls this one time. But it can't be applied to future instances of the falling rock, or to other rocks, or even to the same rock falling in the past. So we can't make any predictions, which makes reproducibility and falsification impossible, and thus science no longer works.

Thanks.

So it is assumption made by science in order to work, as you say. In which case how do we validate it as being a reasonable assumption to make?

John

z8000783 wrote:Thanks.

So it is assumption made by science in order to work, as you say. In which case how do we validate it as being a reasonable assumption to make?

John

Simply pragmatics. If we don't assume it, then science cannot work so it's "reasonable" in that the only way to generate scientific data is to assume it, and since science gives us planes and medicine, it seems like a worthwhile assumption to make. If we wanted to claim that science discovers "reality" or that science attempts to explain how things "really" work, then the assumption becomes much less reasonable, and essentially you can't support it.

That's fair enough in the pragmatic, building a rocket to go to the moon type process then, but what about deducing the age of the Universe?

Does that mean we should be more cautious with statements like 'The Universe is 14 Billion years old'?

John

z8000783 wrote:That's fair enough in the pragmatic, building a rocket to go to the moon type process then, but what about deducing the age of the Universe?

Does that mean we should be more cautious with statements like 'The Universe is 14 Billion years old'?

John

Well we should obviously be cautious with all scientific claims as they are tentative, but more specifically, it comes down to what exactly you mean by "The universe is 14 billion years old". If you mean it in a sense which is more than just a claim that is consistent with other observations that could change if theories require it to, then it would be something that is difficult to support. It's not a ridiculous claim, of course, but it needs more logical support and argumentation - and this is what scientific realists try to argue for.