Do you believe that the universe originated from consciousness?

I would say the most relevant things we both 'know' is that the universe is 'fine tuned' and consciousness has only been observed associated with physical brains.   Which of those is the clincher?

Would it be relevant if all things physical were actually mental?

Of course it would.   It would also be relevant if not everything was mental.

Perfect. Now which theory is correct? I can't think of anything that's not mental. Can you? 

Claiming that conciousness somehow circumvents the need for a cause is special pleading

I never claimed that everything needs a cause.

The material universe is non-mental - or so I believe.   you need non-mental stuff to make brains out of in order that the mental emerges.

If not everything needs a cause then why would the universe need a cause?

How can something that we're mentally conceptualizing or perceiving not be mental? 

According to you things happening with no cause invalidates science. How do you avoid this problem in your hypothesis? 

Because the universe began to exist. It exists contingently. All thing, in our experience, that exist contingently have a preceding cause.

Can you demonstrate that this is the case?

What if the uuniverse has simply always existed in one form or another? 

We were discussing the scientific method which is a cause and effect methodology. The scientific method does not tell us that everything has a cause. 

Then why assume thay the universe has a cause?

Sure, the expansion rate of the universe, when rewinded, condenses to an infinitesimally small point. The second law of thermodynamics. Redshift gravitational waves.

Because it exists contingently and in our experience all things that exist contingently have causes.

We have no evidence of what existed or occurred before the planc time if exist, occur or begore are even applicable terms. For all we know the energy that comprises the universe has simply always existed. Certainly if you can posit a being we have no evidence for has simply always existed I can make a similar supposition about energy which we have evidence for. Otherwise you are making a case of special pleading which is a logical fallacy. 

Supposing that the universe didn't have a beginning isn't consistent with the evidence and, unsurprisingly, isn't mainstream scientific consensus.

I'm just pointing out the problems with naturalism. If free will is the only avenue to avoid a mathematical impossibility then that's the better option.

Btw, are there any other theists that you guys argue with on here? I think the only one I've seen is Janesix.

Is it relevant that external reality has only ever been known or defined according to mental concepts and perceptions?

I think it's very relevant if you want to develop a theory of how brains work.   It seems that brains work by creating an internal model of the external world and we are conscious of the model, not the external reality directly.

I am not sure it is relevant to whether the universe comes from consciousness - in fact it can't be relevant because the universe does not come from consciousness (or so I believe).

Right, but whatever the external reality is, it must be mind-compatible in order for us to be generating an internal mental model off of it. 

If reality is fundamentally mental then this implies that consciousness is fundamental too.

It is actually beyond our current cosmological model to say how the universe began so there is no scientific consensus on the subject. There is a scientific consensus about what the earliest event we have evidence for but that is not the same thing. And I thinknyou know that I do not accept anybtheory which requires freewill until freewill can somehow be demonstrated

We know that determinism is a force at large in the universe. We do not know that freewill necessarily is. One needs to be demonstrated one has already been demonstrated. That is the difference. 

Depending on how you define the implications of the platform (which i may disagree), i think it's a logical platform, yes. 

There is no sense in referring to the beginning of the universe as something other than the Big Bang itself. As Hawking states:

"At this time, the Big Bang, all the matter in the universe, would have been on top of itself. The density would have been infinite. It would have been what is called, a singularity. At a singularity, all the laws of physics would have broken down. This means that the state of the universe, after the Big Bang, will not depend on anything that may have happened before, because the deterministic laws that govern the universe will break down in the Big Bang. The universe will evolve from the Big Bang, completely independently of what it was like before. Even the amount of matter in the universe, can be different to what it was before the Big Bang, as the Law of Conservation of Matter, will break down at the Big Bang.