Today are looking at the concepts of the “possible”, the “impossible”, the arbitrary, and some related issues.
The Possible
Before we go any further, this is my definition of “possible”:
A claim is possible if we possess evidence to support it, and no evidence to disprove it.
To show that a claim is possible, I need to provide evidence to support it. I do not need to prove the claim true or false. However, I need a reason to consider any claim. We must establish the possibility of the claim. The evidence must support the claim. I need to find evidence to support the statement. If you cannot do this, then my claim is arbitrary and detached from provable ties to reality.
Let us take the example of evolution. If I say that evolution is possible, what do I mean? I mean that according to the context of my knowledge, evidence exists for evolution and none proves it to be false.
How much evidence do we need? We need enough evidence to convince us that the claim is at least potentially true. We might have scant evidence, but we need something.
Perhaps, like Darwin, we observe the birds on the Galápagos Islands, and we notice the way finches beaks seem to adapt to their environment. That might not seem like much evidence, but changing bird beaks is excellent evidence of evolution. But is it 100% conclusive?
No, it does not need to be. It does not matter whether the evidence of evolution supports evolution beyond any shadow of a doubt. We do not need to show beyond a doubt that the idea is true. We do not need to prove evolution, only that it might happen.
Come with me to the zoo and let’s watch the chimpanzees. You will probably notice how humanlike chimps look and act. Try denying that many well-known people act much like chimpanzees! Are humans perhaps related to chimps? Chimps are apes. Perhaps humans are too (they are). Perhaps humans and chimps evolved from a common ancestor. Does this show that evolution is true?
No, I have not established that evolution is possible. I am speculating, and that proves nothing. Conjecture holds no relation to what is possible. My speculation does not make it so. Speculation is not evidence. No matter how certain I might be, my conviction does not make it possible. I can guess as much as I wish; however, my conviction does not make it so. A guess without evidence is arbitrary speculation, no matter how reasonable it might be.
What kind of evidence shows this? The evidence says that more primitive apes had features similar to those possessed by humans. Suppose I show ancient apes with large brain cavities suitable for carrying around a big brain. The fossil evidence suggests that, over time, our ancestors developed increasingly more room for larger and larger brains. All else being equal, larger brains are potentially more powerful and, thus, more intelligent (although I am sure you know of many exceptions to this rule).
Over time, ape lineages became increasingly well-suited to walking on two legs. The shape of their pelvises and other skeletal structures become more human and suited for walking. Therefore, it is possible that man evolved from other apes! I did not merely assert this because I imagine it is so. I have considered the large body of compelling evidence and have concluded that evolution is likely true.
Suppose that I lack concrete proof for that conclusion and remain unsure. There are many reasons to believe the claim is likely valid. The copious evidence points to humans evolving from apes.
We’ve made significant strides since Darwin. We know for a fact that humans evolved from other apes. Humans are still apes. It is foolish to deny the compelling and abundant evidence of this. Humans possess the essential characteristics shared by all apes. Our opposable thumbs make it easy to pick up and hold objects. We have a reduced sense of smell, but binocular vision and enhanced perception of color to compensate.
Suppose I declared man evolved from apes. Suppose I lack evidence to suggest that this is true. I assert this because my religious faith tells me evolution is true. Suppose I base this assertion on my worship of Darwin’s foundational book on evolution, On The Origin of Species.
You must provide evidence or reasoning for such an assertion; otherwise, I have no reason to consider it. Speculation is not an argument; it is a faith-based assertion. Faith in “On the Origin of Species” is no better than Christian faith in the Bible.
What is faith? It is believing something without evidence. Faith is when you believe something because you wish it to be true. While evolution is a fact, such an arbitrary assertion is a leap of faith. I have no reason to believe it’s true. It is like asserting that God exists because I want him to.
Although evolution is true, we cannot assume that without evidence. You still need to provide evidence for your claims, regardless of whether they are true or false. Evolution is, as most of know, the irrefutable cornerstone of modern biology. But nobody should believe evolution is true until they see the evidence. Until then, you should not consider it possible.
Without evidence, we cannot say whether something is possible. Suppose your claim is valid, but you have yet to prove that your claim is valid. Nothing is possible until we find evidence to show it is. Until then, your claim is baseless speculation.
According to surveys, between 97% and 99% of scientists accept the theory of evolution. Does this qualify as evidence that it is true? Whether ten, a million, or countless experts agree is inconsequential. You still need evidence to show that evolution is possible.
What Counts as Evidence?
What qualifies as evidence? We need to observe the facts of reality that support our claim. Let us start with the things you can directly observe. Suppose you want to show that it is possible emus exist. Witnessing an emu would prove its existence, resolving the issue. If you go to Australia, you will find millions of emus! Visiting the nearby zoo is a budget-friendly alternative.
Jupiter has between eighty and ninety-five moons. Suppose you wish to prove the possibility of the four largest ones – Io, Europa, Ganymede, and Callisto. Buy a decent telescope, and you can see these for yourself – evidence of some of Jupiter’s moons.
Can we show the possibility of things we can’t directly observe? Things such as atoms or subatomic particles? I have never directly perceived these particles. Where is the evidence of such things?
We must base our arguments on evidence. We must start with what we know and try to find what facts imply that atoms, subatomic particles, or whatever exist. What observable facts support the claim that the things we are arguing for exist? What evidence could you gather? Which experiments could you perform to collect such evidence?
The laws of chemistry would not operate if atoms did not exist! John Dalton knew a lot about chemistry. He deduced that what he knew about it implied atoms. He later discovered considerable evidence of atoms.
Two hydrogen atoms and one oxygen atom make up water. Have we seen this? Can I show you water molecules and point to the atoms? The only rational reading of the evidence supports this conclusion. It is the only explanation that explains why water acts the way it does. The properties of water make sense if they are two hydrogen atoms and one oxygen atom bonded into molecules that form polar bonds with each other.
There is much other evidence. Such as the fact that chemical reactions do not destroy or create atoms; they rearrange them. Scientists also used advanced techniques that allow us to see atoms! We can study molecules and identify the atoms they contain.
1905 was a busy year for the young Albert Einstein. He published four important papers on a wide range of topics: the photoelectric effect, molecular dimensions and special relativity. What was the fourth? A paper on Brownian motion.
That paper is the one of interest. It studied the random motion of particles suspended in a gas; that is, Brownian motion. He argued that Brownian motion is evidence that atoms exist! It helped convince many latecomers that they exist.
What if I want to prove that subatomic particles might exist? We cannot see them, so do we detect them? Thomson had an experiment to detect them. He set up an experiment where a positively charged plate pulled negatively charged particles away from atoms. Thomson’s experiment proved that at least one subatomic particle exists inside the atom – a negatively charged one that he could pull out of the atom.
But he did not see an electron! How could he be sure it existed? By inference. His experiment showed that something was coming out of the atom and causing an observable effect. He called that something the electron! We don’t have to see an electron to know it is there. We can show it is there through clever experimental setups! Many other brilliant scientists have done this.
Science is about more than matter visible to the naked eye. One forms hypotheses and then seeks supporting evidence. Evidence can exist beyond what is visible. Sometimes we observe effects that are evidence of that thing.
I have provided multiple examples of evidence for atoms and subatomic particles. They prove the claim that such things exist. Is this always necessary? No, it is not. To establish the possibility of a claim, you need at least some evidence supporting the claim. A proven claim is both a fact and possible.
Suppose we want to study ancient civilizations. Fascinating! Which was first? Sumer. But how do we know that? Let’s look at the evidence.
A civilization is a large group of people living together with laws, writing, farming, buildings, roads, money, and specialized jobs.
If you go to the Istanbul Archaeology Museums, you can see the cuneiform tablet known as the Code of Ur-Nammu. King Ur-Nammu crafted this around 2100-2050 BCE. It is the world’s oldest known example of a legal code! Given Ur-Nammu was a king of Sumer, it is evidence that Sumer had laws.
That is evidence of one of our criteria, but suppose we then discover it had cuneiform writing. That is two of our criteria. Then, we will find evidence that meets several other criteria. Great! We don’t know of any other civilization, and this one meets several criteria. So, it is possible Sumer is the earliest civilization!