You said,

I'm not going to get into a philosophical debate about what we can rightly consider "observed".

And yet you want to avoid the question put to you by hiding behind epistemology 101.

I addressed these obvious epistemological issues in prior posts.

• in this post I said

  There are very few things (any?) that can be absolutely proven. Therefore we have to weigh the evidence - that is what scientists do all the time. Science is an inductive discipline.

  But we shouldn't throw out the baby with the bath water and say - because we can't know absolutely we, therefore, know nothing. Nor should we say that all is opinion and all opinions are equal.

Given that I had addressed the problems of epistemology before you brought them up - I had hoped that we could take them as understood and that we could move forward and make progress.

I think that we can take it that you deny that the big bang happened. But I would like you to make your position clear.

Do you deny that the big bang happened?

What is your model? Was there always cold matter? Always heavier elements? Always planets with liquid water? Is it turtles all the way down?

: How do you know ? You were NOT there to observe it.

That isn't necessary. And you have gravely misunderstood science if you think that science is: "if you weren't there then you can't know about it".

How did you form that opinion of science? From where?

Did you do science at university level? I ask because you say things about it that I wouldn't expect anyone who has had experience of doing science would say.

Trivial examples of why what you say is nonsense and does not reflect how science is done:

• we now have a measure of the mass of the Higgs boson ( ~ 125 GeV). If what you say is true (that only people who were there can know something) then I suppose that nobody can use that figure unless they were really close to CMS when it was operating.
• And given that we can't directly observe the particles scattered during collisions in particle accelerators... I suppose that we should just abandon particle physics altogether.
• Let's burn the periodic tables and require all chemists to make their own from their own experiments.

Do you not see how silly it is to ask, "where you there"?

: How do you know that
: there was no matter in the beginning?

It was too hot.

: You are ONLY able to form
: explanations which you feel are best supported by observations made here
: and now, to this date. Do you deny that?

No I don't.

The best evidence we have suggests that it was too hot for neutral atoms to exist - you wont find any water soluble molecules in a plasma. And prior to that it was a quark soup (sounds tasty).

Where we differ is that I do not despise evidence and theory. It is plain that you do. You really don't have much respect for such things.

: Regardless, when it may have happened is of zero practical relevance, if it
: cannot be tested.

Which has been done repeatedly. We have made many observations of the microwave background. We have smashed particles together in particle accelerator at higher and higher energies to refine our measurements and theories. It lets us see and predict what would happen at high temperatures and pressures.

We look back in time to observe the early universe, we can observe stellar spectra to measure their chemical compositions. You don't have to make a universe to learn things about it. You can observe the one that you have and you can make small parts of a universe and use what you learn from that.

It is the essence of scientific endeavor.

: Be a good scientist, think critically: TEST your postulation that biological
: life can arise from non-biological matter.

What is non-biological matter? What is the difference between non-biological water and biological water? What is the difference between non-biological protons and biological protons?

We can synthesize nucleotides and amino acids by passing sparks through gases. It is trivial to make them. We see them in interstellar space. They are small, simple molecules - you don't need life to make them.

: Demonstrate that biological life can and does come from non-biological
: matter, with zero biological influence. Do it. Or point to someone who
: did, and has sufficiently documented the evidence and the experimentation
: process. If you cannot, then you have not addressed my point, and my case
: rests

Your point being that life can only come from life? Given an initial sterile universe then it must have come from non-living antecedents. We don't need to make some life to see that. You also have the whole infinite regress problem - how could life start if it can only come from existing life?

: There is currently no demonstratable, observable data that
: biological life either has a "vital spark", OR that it can
: ever arise from non-biological matter.

This is a God of the gaps argument.

We can see that fundamental biological building blocks are easy to make. We can even see how the two most common RNA nucleotides can be formed in biologically plausible conditions - they are of the correct chirality and are the most resistant to UV radiation and so can become concentrated in water exposed to UV.

I think that in time your gaps will become smaller and smaller.

Do you insist that any experiment carried out by a person constitutes biological input? Are you going to deny the validity of all experiments carried out by people? I think that you have already done this but I'd like to hear you confirm or deny this.

: The default stance is only what we know: We observe biological organisms, and
: we observe non-biological matter. There is a difference, and we do not
: (yet?) know how to cross that mysterious boundary that distinguishes
: non-biological matter from biological organisms.

What is this difference that you talk about? Define it. What is biological matter? What is non-biological matter?