How Can We Know What We Know?

We all, I think have a sense that we know certain things. Pieces of knowledge that come together to form our views and ideas of the world and how it works. I know that I enjoy chocolate ice cream and peaches. I also know that the earth goes round that sun and, that if I leave an ice cube out in the sun, it will melt. But how is it that I know theses particular things? Why did I choose these particular examples?

Allow me to explain. There are some things that we can know subjectively. That is to say that we know them from our own personal experience of existing in the world. My like of chocolate ice cream and peaches falls into this category. I know that I like these things because when I eat them I experience pleasure. Philosophic discussions about what it means to experience pleasure aside. I feel confident in saying that I know I like chocolate ice cream and peaches. And I'm sure a functional magnetic resonance imaging scam of my brain while I eat these things would back me up. But thats a subjective experience. What about things that I can't or don't experience?

How do we know that the earth goes round the sun? From our perspective it certainly doesn't seem that way. And indeed if I were living in a different time I may have rubbished the idea that the earth on which we stand is hurtling though space at 108,000 km/h around a giant ball of light. I mean really, How absurd. And yet we know this to be the truth. The reason for this knowledge is objective evidence. There is evidence, completely independent of anything we can say or do, that points towards this conclusion. There are numerous supporting theories and branches of science. That would have to be modified or discarded if it were found not to be true. There are countless observations and experiments that have been performed that are consistent with this reality. All this converging evidence leads me to believe that the earth, does indeed, go around that sun.

Now I will turn to the ice cube. I picked this particular example because, unlike the previous one, it is obvious to everyone with experience of ice that it will melt if left out in the sun in temperatures above freezing. So this is something we can know without having to make and rigorous measurements or observations. Just put the ice cube down and watch it melt. But I choose this example for a reason. The ice cube melting is perfectly consistent with all that we know about thermodynamics and the chemical and physical properties of water. If you so wanted to. You could take all the theoretical knowledge about the phenomenon of melting ice and create a mathematical  model of the ice melting. This model would then allow you to predict the exact way in which the ice would melt and these predictions would match what you observe.  

So. What is that point I'm trying to make here. Well my point is am important one. And I think it is very often over looked when explaining science to the general public. And the point is that science must be consistent with our observations of how the world actually works. That's really important. And it is one of the most important things that allows a distinction to be made between actual science and pseudo-science. In science. When the model of reality and reality disagree. Then it is the model that must be wrong. This is what gives science the power to discover what is true and what is real in an objective way.

So how do we know what isn't true? Well I'm going to once again turn my skeptical eye onto CAM. And particularly that affront to Haman reason, Homeopathy. How do we know that Homeopathy is bunk and doesn't work. Well, it fails every time it is properly tested. There are no well constructed, well performed tests that have shown an effect for homeopathy. Strike one. If something cannot be shown to have a real effect in the real world then there is no difference between this and it having no affect at all.
Homeopathy has no plausible mechanism of action. This means that there is no way within our current scientific model of reality that allows Homeopathy to work. Remember what I said in the previous paragraph. Our current model of reality agrees with what we have been doing and observing for the last 200 years or more. If homeopathy worked. We would need to change and reinterpret huge areas of physical and biological science. Strike two. If something is not consistent with the current scientific model. It requires a lot of good quality proof for it to be accepted.              
The only evidence of the effectiveness of homeopathy comes from anecdotes. This is often a tough point for some people to grasp. But anecdotes are not evidence. There are simply too many things that can affect an individuals experience that we cannot consider such experience proof of anything. This is particularly so in CAM. For example. A patient with a sore wrist takes a homeopathic remedy and feels better. How are we to know that the remedy was responsible? It may have been the remedy. Or it may have been what he ate for dinner. Or that a swallow happened to pass over his head at precisely the right time to realign his chakras and restore the flow of subtle energy to his wrist. Or he may have just healed on his own had he not taken the remedy. The point is that we can't know. That is why we test these things scientifically. Such testing removes the possible ambiguities and allows the one variable to be assessed. When this is done. Homeopathy fails. Strike three. Anecdotes are  not evidence. When the only positive evidence for something are anecdotes. The likelihood if it being real is slim.

So to sum up. When it comes to real questions about how the real world works. We have to learn to step outside our own narrow, biased and flawed perceptions and embrace objective evidence and rationalization. This is the only way we can form a coherent world view. This is the only way we can truly know what is real and what is not. And the only way we can tell truth from fiction.