exchemist

That would seem to indicate there is not much to worry about, at current levels of exposure.

Oh so you mean candle soot. I see. I'm not sure I would expect that to do anything. And I've just tried it- having taken the elementary precaution of removing the metal foil and the metal disc securing the base of the wick - and nothing happens.

I don't follow you. Dioxane is present in some cosmetic preparations, at <10ppm. At that concentration, yes, I would rub it on my face without worrying too much. Except that, being a bloke, I don't use cosmetics......... unless you count shaving lotion.

What graphite is this?

Because it does scientific research and produces results. You can read about what people studying it do here: https://en.wikipedia.org/wiki/Astrobiology They don't just speculate about life on other planets. They study life here in extreme environments, to see what range of environments could support the kinds of life we have here on Earth. They study the environments of other astronomical bodies. They look at things such as the chemistry of meteorites and comets, etc. And they publish the results of these studies.

Well pretty different, it seems to me. Dioxins, being aromatic, are chemically related to phenols, while dioxane is an ether. Dioxins are persistent pollutants while dioxane biodegrades. Dioxins bioaccumulate, whereas dioxane apparently doesn't. These differences in behaviour are presumably related to dioxane being water soluble while dioxins are lipid soluble.

And your petulant sarcasm, in response to getting your previous wrong idea rejected here, is not hostility? Look, if you want to make a serious point, and are willing to respond constructively to the responses you get, people like me will be more than happy to take you seriously, whether you can spell or not. But you have yet to show any sign of being able to do that - and by your own admission this thread was not started in that spirit. If you take the p***, you must expect that others will do so too.

It's spelt "meant", and "your". The sarcasm (not really irony) of your post was very obvious, but as it raised no serious point of discussion I thought I might as well correct your spelling.

It's spelt "exist".

Hang on, that's about dioxins, not dioxane. They are quite different, surely.

Why would you want anything with similar properties to dioxane? So far as I am aware, dioxane is not used to make cosmetics. Trace levels (<10ppm) can sometimes be present, as a byproduct of the manufacturing process for some of the other ingredients, but it seems to serve no purpose in cosmetics.

What's to stop it pulling the other tree, the one used as the anchor, out of the ground instead? Or do they carefully select a tree that they think is more firmly embedded than the stump? Of course, there are other methods nowadays:

To return briefly to the other points you raised, yes, I'm quite happy with the idea that theories involve reasoning from assumptions that are based on generalisations from observation. I still maintain that axioms is the wrong word for them, as these things are based on observation, and subject to being abandoned if later observations show something different. They are purely empirical. I also fully agree that there are questions science can't answer, for want of suitable observations to test any hypothesis, the origin of the universe being one of them. Whether this will always be so, I am not sure. There does seem to be a fundamental difficulty in finding an explanation for the all of the order ("laws") in nature - though some "laws" turn out to be derived from others. Where I think you go off the tracks is in suggesting that we must have an explanation for the origin of the universe, even though science cannot provide one (First Cause and all that).

I don't understand why you say "chlorine is still king", as if borates and chlorine were alternatives. As I understand it, there is no suggestion that use of borates is an alternative to chlorine. They seem to be a buffering and water conditioning agent, not a disinfectant. Why has use of borates been abandoned?

What I mean really is that in science "truths" are generally not claimed at all. You don't find people claiming "truth" in science papers, or even in university textbooks. What you find, generally, is people claiming that such-and-such is "consistent with" some model, or with a set of observations, not that it is "true". When I say that in science all "truth" is provisional, it is a way of saying it is not claimed as such. Truth is much more the currency of the logician or philosopher, rather than of the empirical mindset of the scientist. But anyway this is good, because we seem at last to be on the same page regarding what science seeks to do. I feel it is important to keep the idea of models (of aspects of nature) in mind. History shows that models in science are often found wanting and revised or replaced, Newtonian gravitation and mechanics being classics. What I find important to note about these, however, is that we still use them, all the time. So it not that they are "wrong", having previously thought to be "right", but that we now recognise they are incomplete and have limitations in their scope of application. In chemistry, which is far messier than physics on account of the complexity of the multi-electron atoms of the Periodic Table, we quite commonly use more than one model for the same thing, according to circumstances. We are aware that each is a simplification or an approximation, and we're used to pulling out the best model for the job at hand, knowing that they are connected at a deeper level and what the limitations of each will be. In fact, I wonder sometimes if the chemist is even more consciously aware than the physicist of the idea that theories are just models.

Just a minute. Can we please first of all agree that I am not asking you to "elevate science and theories to the status of unquestioned absolute truth" ? Secondly, are you now willing to accept what I have been saying, which is that in science all "truths" are provisional, there are no "absolute truths" and that there is nothing that cannot be challenged? If we can agree this, we can proceed to the other points - if we both have the stamina.

I think you and I have got to clear up the last point before it is worth discussing anything else. What you accuse me of is the polar opposite of what I have been saying to you throughout. - I have been saying that all scientific theories are mere models of aspects of nature. - I have been saying there are no axioms, just propositions, open to testing by observation. - I have been saying these so-called "laws" are made-made representations of aspects of the order we perceive in nature. I have, in effect, been saying there are no absolute truths in science whatsoever, and that everything is open to challenge. Yet, you seem determined to hear me saying what your own prejudices apparently assume I should say, while ignoring what I have actually been saying. Why?

Indeed. So, also taking into account the other responses, it seems you are right in thinking that charcoal is fairly inert, biologically, though as some posters have pointed out it does tend to adsorb substances and can be a good substrate for the growth of micro-organisms. But, to return to the question you originally asked, only a small proportion of the carbon in cellulose is converted to charcoal in a fire. Most is burnt to CO2, or CO, which itself can burn to CO2. So only a very small amount of carbon is sequestered in the form of charcoal. (In fact a lot more carbon is sequestered by conversion into carbonates, in the sea.) Meanwhile, a great deal more CO2 is being liberated, both by the burning of fossil fuels and by natural processes, e.g. volcanism. If you are interested in the various natural processes involved, you can look up the "carbon cycle" and find descriptions of the carbon sources and sinks and how they inter-relate:https://www.earthobservatory.nasa.gov/features/CarbonCycle

And......my hovercraft is full of eels.

Yes, I have seen it once, in a "tank farm" at a lubricating oil blending plant, during a thunderstorm. After a lightning strike, I think to one of the tanks, a glowing ball, perhaps about the size of a football, or a bit smaller, appeared, which moved along a pipe track for a few seconds and then vanished. I don't recall any sound, but I was in my office looking out through a closed window, so I can't be sure if there was any sound. This was in 1982 or so, so there were no mobile phone cameras to take a picture. I believe the phenomenon is now at least recognised as not being an illusion, but I am not aware that anyone has been able to account for it convincingly. Perhaps others will know more. Light is radiation, not matter, so it can't be solid, liquid or gaseous. Something emitting light, presumably.

Well if you want to call these validated assumptions assumptions still, I don't mind particularly. But I do object to your attempt to denigrate the defining feature of science as an approach to understanding the world. A hypothesis is not a theory until it has been tested by reproducible observation of nature. This strictly empirical foundation of science is absolutely basic to the scientific method and is central to its success. Trying to belittle this by mixing it up with historical influences is an error on your part. I see you persist with this wrong notion of elevating laws to the status of an axiom, when I have been at pains to explain this is not what science does and that axiom is a bad term to use. There is, to my mind, only one "assumed truth" in the whole of science, and that is that there is a reality that we can model by observing nature. If you think there are others, please give me an example of one, to help me understand what have in mind.

This looks like a textbook example of the Dunning-Kruger effect.

Surely the point about all scientific theories is that they are rooted, not in assumptions, but in reproducible observation of nature. So, while one may make assumptions in constructing a hypothesis, the hypothesis is not a scientific theory until it has been put to the test by making observations. If it has passed the tests, then the assumptions made have been shown to be consistent with nature, so they are validated to some degree and cease to be mere assumptions. I guess one can argue the toss about whether they still qualify as "assumptions" or not, in those circumstances, but they are at least not "just" assumptions now: they are assumptions that are a good fit to reality.

Well, I see what you are getting at, in that the conservation laws are fundamental to physical science (temporary deviations from them in QM notwithstanding.) However my - rather simplistic - understanding is that the conservation laws are derived - from Ockham's Razor by way of Noether's Theorem, if you like - in that if we assume the (other) laws of physics do not change with time and place, then the conservation laws are the consequence. I suppose you can argue that that assumption is axiomatic, but really it is just observing and then assuming that what we observe is generally applicable, by invoking Ockham's Razor. Isn't it? And then, I suppose, there are things like the postulates of QM. But a postulate is not an axiom. The choice of term indicates it is a model being put forward, not something taken as definitively true. On which point, I couldn't help noticing that in one of your other posts you say: "The laws of physics are unproven and unprovable (science relies on inductive reasoning) therefore - like axioms in mathematics - they are assumed to be true, taken for granted, believed, I make no apology for labelling these as "axioms" it is a legitimate label epistemologically speaking. " This seems to betray a misunderstanding of the nature of science. Yes of course theories in science, including those we dignify with the description "laws", are unprovable. Science does not deal in proof. But, per Popper, they are all in principle falsifiable. That means that science does not assume them to be true. They are not "taken for granted". They are provisional models of nature, that is all, ready to be overthrown if new observations cannot be reconciled with them. Now, sure, in daily work the scientist relies on a multitude of these laws without questioning them, but he or she is - or should be - always implicitly aware that they are man-made models, open to challenge. So I don't think the term axiom is very helpful in describing them.

Yes.