Here She Be — The Battlements

Hume says that a wise person proportions his or her belief to the evidence. What does he mean by this?

     This idea is actually at the core of Hume’s constructive argument, as he creates his definition of causation and reasoning. The statement itself comes from a fairly easy to accept bit of reasoning. When we choose to believe in something, we do so for a reason. That reason is typically some sort of preference. For instance, we could choose to agree with one philosopher because he is easy to read and understand, although his argument does not seem as sound or as well supported by evidence as another philosopher, who we might also choose to agree with. The wise person agrees with the philosopher who has more evidence, as his argument will be better supported; also there is the possibility that the wise person agrees with neither person because there is insufficient evidence for both arguments, or there is sufficient evidence to the contrary of both arguments.

     Hume’s picture of causation gives some better insight into what Hume means by this and why he thinks it is true. According to Hume our ideas of cause and effect are typically somewhat flawed because we believe that there is a necessary connection between the two; however, we can never know for certain what the connection between one event and another is. What we can do, though, is judge based on previous experience. Essentially, I see the same thing happen over and over, and eventually I make an association between one thing and what I see typically in conjunction with it, and I dub the first event cause and the following event effect. For instance, I kick a soccer ball and it moves. I have kicked many soccer balls many times in my life, and they have always moved. I have made the association in my mind that when I kick a soccer ball it moves, and I have also converted this idea into one of cause and effect, where my kick is the cause and the ball’s movement is the effect. I make this association even though, admittedly, I can never know for certain the relationship between the kick and the movement—the connection between them. I have simply witnessed the conjunction often enough to make my inference.
     The experience of seeing the two things in conjunction regularly amounts to a kind of evidence. Similarly, testimony can be a kind of evidence. When weighing testimony, we decide how well it conforms to our experience, which is our pre-existing evidence of the way the world is, as well as a number of other factors, such as the level of experience of the person presenting the testimony. These other testimonies also amount to a kind of evidence.
     The wise man according to Hume weighs what he believes against the evidence for it, and then decides based upon that.
     Part of this relates directly to Hume’s argument regarding miracles as well. A miracle is a transgression against the laws of nature. All experience someone has in life is in accordance with the laws of nature with each new experience conforming in some way to other experiences. There is a chance that a new experience might be considered a miracle if it is deemed as something new yet completely different from all other previous experiences in that it transgresses the laws of nature. Still, the reasons for choosing this based on evidence from experience, or any evidence at all really as Hume suggests virtually all of our evidence is a result of experience, are almost non-existent. Take for example a baby that has just been poked in the eye for the first time. And let us assume that the baby can reason the way we can, or makes inferences the way we do. The baby will initially accept that the poke in the eye is the way the world is, rather than some miraculous event, even though the event is spontaneous, unexpected, and unprecedented. Perhaps the baby already knows that being poked can hurt, maybe not, but he will eventually know this. If perhaps the baby did think that the poke was a miracle, when he learns that being poked hurts, he will come to understand that what he experienced was not a miracle but the way the world is. This is the way everyone develops their understanding in life with all prior experience eventually conforming in some way or another as a part of the larger understanding of the way the world is; however, there are those who claim to have experienced miracles. And these people choose to accept that what they have experienced in a miracle is something that will never conform to any of their past experience, even though everything up until then has. It will never be conformed to their past experience because all their past experience was in accordance with the laws of nature, which miracles are not. If I have kicked a thousand soccer balls, and they all move when I kick them, I will assume that when I kick a soccer ball it will move, not turn into a lion. However, believing in a miracle is the equivalent of believing that something along the lines of kicking a soccer ball and believing it turned into a lion, as both of these things are choosing to believe in something that contradicts all previous experience and how all previous experience relates. If I have always found my experiences to coincide with the way the world is, even when I am not immediately aware that this is the case, why should I suddenly assume that something I experience does not work in this way? A wise man will not because he bases his belief on his experience.
     The proportioning part of this relates to the ability for belief to be in degrees related to how certain we are of something. If we have a lot of evidence for something, then we are fairly certain of it and will believe in it more. If we have less evidence, we will be inclined to believe less in something. This also relates to miracles because we have no evidence to ground a belief that something is a miracle, while we do have evidence that there is an explanation for an event, even if we do not have it. A wise man, according to Hume, does not believe in miracles because there is no evidence that allows that he should believe in them. There is however evidence to the contrary. Similarly we proportion the amount of belief that we have in anything to the evidence that we have for it.