[LeGrande]

Which leads to a curious question: How do we know these are life forms? ... Or is this a baseless quibble?

Actually that is a very good question and goes to the heart of the problem, especially with the discovery of the giant viruses.

In biology it appears that there are very few places where a fine line can be drawn.

[Alamo-Girl]

betty boop: Which leads to a curious question: How do we know these are life forms? ... Or is this a baseless quibble?

LeGrande: In biology it appears that there are very few places where a fine line can be drawn.

Indeed, that is a great example of why the Newtonian paradigm in biology is inadequate.

If we turn to Mathematics, more specifically Information Theory, the answer to "what is life v. non-life/death in nature?" is readily apparent.

Information (Shannon) is the reduction of uncertainty (Shannon entropy) in the receiver (or molecular machine) as it goes from a before state to an after state.

It is the action of successful communication, not the message itself (e.g. DNA.)

Dead biological organisms also have DNA. Moreover, the Shannon model applies whether the message is biological, Shakespeare's Hamlet, a keystroke, etc.

So it is correct and useful to observe that that which is alive in nature is successfully communicating. If communications cease, the thing in nature is dead. If it never could communicate, it was non-life.

This definition is not stumped by the objects which are anomalous to descriptive definitions, e.g. metabolism in living things.

For instance, under the Shannon model bacteria are autonomously and successfully communicating and mycoplasmas and mimiviruses are autonomously and successfully communicating as parasites. The dormant anthrax spore is alive in stand-by, awaiting an interrupt to begin communications. And viroids, viruses and prions - which are not autonomous - nevertheless are part of the communication as “noise” or deformations in the channel, whether for good or for ill (successful or not).

In the Shannon model, the latter are like broadcasts or "bleeding" of messages or message fragments into otherwise autonomous channels.

On the one hand it can be seen as the pathway for mutation under a materialistic evolution model.

And on the other hand, it can be seen as a pathway of God speaking a thing, function or whatever into existence.

The heavens declare the glory of God; and the firmament sheweth his handywork. Day unto day uttereth speech, and night unto night sheweth knowledge. [There is] no speech nor language, [where] their voice is not heard. – Psalms 19:1-3

God's Name is I AM.

[betty boop]

In biology it appears that there are very few places where a fine line can be drawn.

Indeed. Which perhaps accounts for the claim that biology need not be "rigorous" in the sense that physics is rigorous; i.e., can be conceptualized and expressed in mathematical language.

Yet it seems theoretical biology aims to do this very thing, sooner or later.

We live in fascinating times, dear LeGrande! Thank you so much for writing!