Anyone can speculate about these topics whether they are scientists or not, though I may give some credence over above a laymen when it comes to a scientist even its not their normal field.
Why? I am a leading expert in a certain field (within the information science) - it means I know a lot about a very narrow thing and I know very little more than a layman or maybe an undergraduate about some subjects within my own discipline and I'm certainly no more than a layman outside of my discipline.
There are simply not enough hours in the day to keep on top of the cutting edge in a number of fields, all you generally do is dilute yourself by trying.
Most of your posts have this weird uncritical view of people in white coats - it's an underlying theme with you.
It ironic though--as I've pointed out before--how often even experts or developers in certain tech fields don't always see the big picture(as some do here on this BB). Its why I admire the visionaries and people who do.