This is kind of a work in progress at the moment, and should be considered as a draft.
If you're familiar with my writings on the faith page, you'll get the idea that I don't think faith is a good thing. If not, I suggest you read that first . . .
This page came about because of an argument that was put to me recently that science is itself based on faith, and in addition to this, so was atheism. I think I've already covered the atheistic response to this on the faith page, so I'll not go into it further here, but as to the other question . . .
So, is science based on faith, or even on assumptions or beliefs? I think not. I think some of the confusion over this issue arises because the word 'faith' has multiple meanings which are similar but distinct. Science may have aspects that rely on one of these meanings, but I don't think that is what the original question was referring to;
There is faith in the sense of expectation. As an example of this, when you walk across the road at a crossing, you have faith in the drivers of the cars that they will honour the red light in front of them, and not accellerate forward and run you over. If one of them is revving it's engine, or inching forward, then your faith in this is reduced, because an observed phenomena is contradicting your expectation of behaviour.
Then there is faith in the religious sense, where it refers to nothing tangible or pertaining to scientific method.
I would contend that science has practical aspects which rely on the first meaning of faith in that it assumes that if something does something in a lab reproducibly for x repetitions, it will do so indefinitely etc (although it would be able to cope with it if this behaviour suddenly changed, so even this is arguable). It has nothing whatever to do with the latter definition of faith.
I would also contend that science does not contain any inherent base assumptions whatsoever.
The source of the argument that lead to this page existing was the leaflet 'Can I believe in Christianity' by Ken Taylor - a leaflet which purports to persuade those of a scientific bent to the christian faith. Here's the bit in question;
An illustration may help to clarify this fallacy. Let us assume that we believe an object can be moved only by physical pressure. In that case we would believe that a metal ball on a table could move only if pushed, blown or rolled. Suppose however that someone should put a magnet under the table directly beneath the ball and then move the magnet. The ball would move with the magnet. Believing however that only physical pressure can move an object we would first assume that someone had jostled the table. If the magnet were moved again with no one touching the table, the ball would of course move again. But, we may say, someone may have blown the ball. When this hypothesis has been disposed of by even more careful demonstration, it ought to become obvious, if we are honest, that our theory was somehow incomplete, and that the basic assumption that only pressure moves objects must be wrong. It would be unfair and inaccurate to rule out the power of the magnet before examining it.
I should at first say that if anything were to convince me of the falseness of christianity, this would be pretty near the top of the list, which has I suppose a certain irony to it, given the intent of the author.
The above argument misses the point entirely about scientific method. It seems to assume that science limits itself to explanations that fit within the laws that it has already defined, while contrary examples litter the history of scientific research.
I think a good definition of science would be to say that it starts from stating that nothing at all exists, and then trying to prove itself wrong. Proving itself wrong is the key point here - the whole process of research is intended to attack itself strongly, and only conjectures, hypotheses, theories (all different things, no points on a scale of certainty) which can't be pushed over survive.
But just because they can't be pushed over, that doesn't necessarily mean that they are true in any objective sense of the word. It merely means that they are sufficient to explain the applicable phenomena that we have been able to observe to date. There is a definite trend in science that any new technology that allows us to look closer, further, and more detail at something will reveal some information that doesn't fit into the current models, and so the models have to be re-designed to incorporate the new information.
To get to specifics on the quoted section, suppose that science didn't know about magnetism. It would indeed eliminate first the table movement and the blowing of air, as it makes sense to eliminate the simple explanations first. Having eliminated those it would have gone into the standard sequence of thinking up alternative methods whereby the ball might have moved, and methods for testing these hypotheses. It would have eventually, by trial and error, arrived at something approaching a basis for the action at a distance properties of magnetism. It would not have restricted itself in the way described.
Further, science has I think made one critical error in referring to things as 'Laws' - this causes a lot of confusion which is apparent in the quoted section. Scientific laws and Legal laws have nothing in common. In science, initially you have an idea, or conjecture. You take this, and phrase it in such a way that it explains some observable phenomenon, and also gives testable predicitions about other phenomena. At this point it is a hypothesis. Once you test these other predictions, you find out not whether your hypothesis is true (you never find that out), but whether your hypothesis is possible. Once you have narrowed down the available hypotheses to just one, you can use it as the basis for a law, but it isn't a law that defines a phenomenon, it is one that describes it. Scientific laws are maps of the universe we observe. Saying that something won't happen because it goes against natural laws is like saying that a road won't exist because it isn't on a map (or will exist because it is on the map). It's nonsense.
Clearly, our scientific map is more accurate in some areas than others. Some of the lines on it have been drawn there for a very long time, but even here the map is never completely accurate. For example, Newton's theory of gravity produces a description of the universe which is very close to the universe we observe. But it isn't identical - there are small differences between the orbit of Mercury, for instance, in Newton's theory and in practical observation. The map didn't completely describe the territory there until Einstein came up with a more advanced, and much more complex theory which allows for these differences. The result was a more accurately drawn map of how the universe works.
To continue that analogy, you could look at advances in scientific research as more and more detailed surveying . . .
One assumption which science does make however is that all observable phenomena derive from explicable sources. In other words there are no effects without causes that we can also detect. Quantum mechanical uncertainties have an influence here, but that aside, the upshot is that if you repeatedly observe that an object accellerates at a rate of 9.8 metres per second squared when released above the floor, then that is due to the effects of gravity, and not due to some supernatural cause.
The clincher there is that if it is some supernatural cause that is leading to the effects you are observing, and (as in the christian position), it is an entity with free will, then there is no guarantee that it will continue to have the same effect over time. One key aspect of the testing of hypotheses being reproducibility . . .
Some other fundamental differences between science and religion;
science admits openly that it cannot at present explain everything. There is work yet to do. And I suspect there always will be - you will never know that the map is absolutely correct.
Religion on the other hand claims it can give all the answers. That immediately makes me very suspicious of it.
Science asks, demands even, that deep questioning is made of it. If a scientist states that they have been unable to disprove some hypothesis, then other scientists don't take their word for it, but try it themselves and see if they are able to reproduce the same observations. Only then is something accepted as a possibility.
As mentioned above, you can never be absolutely certain that a hypothesis is objectively true. Some religious arguments use this as a leverage point and say that you cannot therefore disprove the existence of God without collecting infinite amounts of evidence. This is true, and is an example of a comment I make on the Faith page that infinity is a mathematical construct only, and that referring to things in the real, observable universe as infinite is flawed because infinity does not exist there. It is however, perfectly possible to say that God does not exist in any place that science has looked thus far (and that's a pretty big space, and growing all the time). The same is true of the concept of the soul, incidentally.
To be continued and structured rather better than it is at the moment.