The first cause, causing other things to exist, through a mechanism that we do not know, sounds more reasonable than things just coming into existence from nothing and without a cause.
I find the idea that either the original substance had no beginning or came into being uncaused from nothing paradoxical, since each is counterintuitive. I also consider it a logical error to look at only one of those two, call it counterintuitive, and reject it on that basis. Also, calling that first substance conscious is unjustified. Why would it be, unless it evolved,in which case it's just another product of nature like man.
The scientific view point assumes the existence only of those things that it can test.
Only things capable of interacting with other things, which is what detecting means, can be called real or said to exist. Reality is the collection of objects and processes interacting with one another in space through time. To postulate that there exist things that cannot interact with what I call reality is to make an unfalsifiable and thus meaningless statement, and would exclude a god capable of creating or modifying our reality. Once you call something untestable or undetectable - and not just contingently so, undetectable for now until the right devise is invented - you are declaring it irrelevant and causally equivalent to nonexistent.
Assuming that and then defining life accordingly is not a proof that the definition is true.
Did you mean complete? The scientific narrative will be the simplest one that accounts for all relevant observations. We define life according to what we see, and we understand it as a far-from-equilibrium chemical state. No substances or forces not readily available are needed to assemble or maintain an organism through its lifespan, so none are included in the scientific narrative. The believer wants a job for his god, so he invents one. "God is the spirit part of a living thing." "What is that exactly, where can we find it, and what is it needed for that the chemistry alone cannot do?"
Why not attribute a spirit to a burning light bulb? "What is it needed for?" one asks. "It's the light force that makes matter able to glow. Let there be light, and the bulb was infused with the spirit." "We don't need that to account for the observed behavior of incandescent matter." "But you can't prove that the spirit of the bulb doesn't exist." "No. Nor need we to ignore the idea until we need it to explain something."
Those who define life in other ways can see a different nature in those things that are alive compared to a pile of chemicals,,,,,,,,,,,,,,,,,,, especially when those things are conscious.
Scientists also see a different nature in living matter and nonliving matter. Not all collections and arrangements of chemical are alive, but those that are remain assemblages of chemicals kept in far-from-equilibrium states by channeling ambient energy (sunlight, nutrition). A living organism is a dissipative structure like a tornado, hurricane, the red spot on Jupiter, and the polar hexagon on Saturn. I mentioned this yesterday with the Jeremy England link. That energy is your "spirit."
It's the same as the spirit that brings the tornado to life, organizes its elements into a twister and animates it going through town destroying the landscape. Like living organisms, they are all far from equilibrium structures that would have nearly zero chance of occurring without there being a pressure to have the ingredients come together and function cooperatively. This occurs when a system is channeling energy, and is frequently associated with energy (heat) sources like atmospheres and oceans that function as thermal reservoirs:
- "A Dissipative Structure is a thermodynamically open system operating far from thermodynamic equilibrium, that exchanges energy, matter, and information with. the external environment. In this kind of systems, organization can emerge through a spontaneous self-organization process"
- "A thermal reservoir, also thermal energy reservoir or thermal bath, is a thermodynamic system with a heat capacity so large that the temperature of the reservoir changes relatively little when a much more significant amount of heat is added or extracted. As a conceptual simplification, it effectively functions as an infinite pool of thermal energy at a given, constant temperature. Since it can act as a source and sink of heat, it is often also referred to as a heat reservoir or heat bath. Lakes, oceans and rivers often serve as thermal reservoirs in geophysical processes, such as the weather. In atmospheric science, large air masses in the atmosphere often function as thermal reservoirs."
Hopefully, you can read the titles below. This is the ground-breaking work of Belgian physical chemist Ilya Prigogine. I read only the leftmost of these books, decades ago, but it was enough to get the gestalt of this concept of dissipative structures and semi-stable, far-from-equilibrium states like living things:
Life is another example of a dissipative structure, a high level of self-organization to a far from equilibrium position that channels energy that it uses to maintain that status.