The problem is with the definition of a miracle in the first place. Here's what the Catholic Encyclopedia has to say:
(Latin miraculum, from mirari, "to wonder").A cynic might think that the last sentence above is deliberately confused and designed to give the appearance of refuting Spinoza and Hume whilst not redefining a miracle to bring it within the realm of nature, and thus not miraculous. Both Spinoza and Hume had pointed out essentially the same thing - that miracles are, by definition, unnatural or 'super-natural' and are thus a violation of natural laws. To argue that a 'miracle' which is 'above or outside nature' is not contrary to nature is absurd if one accepts the normal definition of 'nature' as everything about the material Universe.
In general, a wonderful thing, the word being so used in classical Latin; in a specific sense, the Latin Vulgate designates by miracula wonders of a peculiar kind, expressed more clearly in the Greek text by the terms terata, dynameis, semeia, i.e., wonders performed by supernatural power as signs of some special mission or gift and explicitly ascribed to God...
The wonder of the miracle is due to the fact that its cause is hidden, and an effect is expected other than what actually takes place. Hence, by comparison with the ordinary course of things, the miracle is called extraordinary. In analyzing the difference between the extraordinary character of the miracle and the ordinary course of nature, the Fathers of the Church and theologians employ the terms above, contrary to, and outside nature. These terms express the manner in which the miracle is extraordinary.
A miracle is said to be above nature when the effect produced is above the native powers and forces in creatures of which the known laws of nature are the expression, as raising a dead man to life, e.g., Lazarus (John 11), the widow's son (1 Kings 17). A miracle is said to be outside, or beside, nature when natural forces may have the power to produce the effect, at least in part, but could not of themselves alone have produced it in the way it was actually brought about. Thus the effect in abundance far exceeds the power of natural forces, or it takes place instantaneously without the means or processes which nature employs. In illustration we have the multiplication of loaves by Jesus (John 6), the changing of water into wine at Cana (John 2) — for the moisture of the air by natural and artificial processes is changed into wine — or the sudden healing of a large extent of diseased tissue by a draught of water. A miracle is said to be contrary to nature when the effect produced is contrary to the natural course of things.
The term miracle here implies the direct opposition of the effect actually produced to the natural causes at work, and its imperfect understanding has given rise to much confusion in modern thought. Thus Spinoza calls a miracle a violation of the order of nature (proeverti, "Tract. Theol. Polit.", vi). Hume says it is a "violation" or an "infraction", and many writers — e.g., Martensen, Hodge, Baden-Powell, Theodore Parker — use the term for miracles as a whole. But every miracle is not of necessity contrary to nature, for there are miracles above or outside nature.
Source: The Catholic Encyclopedia (accesses 28 April 2013).
na·tureSo there can be little doubt, despite what the Catholic Encyclopedia tries to imply, that miracles, at least as they are defined and understood by those who promote them and those who believe in them, are things which have no natural explanation or, in Spinoza's and Hume's words, violate natural law. In fact, Spinoza goes further and says natural laws cannot be violated, so even if miracles appear to be unnatural, this is simply due to the ignorance of the observer. Miracles are simply natural events for which we don't yet have a natural explanation.
1. The material world and its phenomena.
2. The forces and processes that produce and control all the phenomena of the material world: the laws of nature.
Source: The Free Dictionary (accessed 28 April 2013)
Nature, in the broadest sense, is equivalent to the natural world, physical world, or material world. "Nature" refers to the phenomena of the physical world, and also to life in general. It ranges in scale from the subatomic to the cosmic.
Source: Wikipedia - Nature (accesses 28 April 2013)
And this is where the problem begins.
We all want to believe in impossible things, I suppose, to persuade ourselves that miracles can happen.Because there can be no natural explanation there can be no evidence other than someone else's word for it that a given miracle actually happened. Additionally, because miracles are unnatural the likelihood of them occurring spontaneously is zero - otherwise they could have a natural explanation. Even if we are charitable and allow that they are not actually impossible (how can something that happened be impossible?) but are just so highly unlikely that a natural cause can be excluded, or at least given a lower probability that a supernatural or 'divine' intervention, we are left with a highly unlikely event.
Paul Auster, The Book of Illusions
We are, in effect, being required to take someone's word for it that a highly unlikely, even impossible, event actually happened, without them supplying any evidence. Why on Earth would any rational person do that?
How many people would you believe if they told you, without the slightest scrap of evidence, that, for example, they had just seen the Virgin Mary appear out of thin air in Central Park, New York, or a man fly to Heaven and back on a winged horse from Hyde Park, London? How about if they claimed to have just witnessed a man satisfy the hunger of thousands of people with a few loaves of bread in Montreal, Canada?
What other explanations would you consider first? Which other perfectly natural causes could there be for that person telling you such a thing? Note: 'because it's true' is only one possibility amongst many. Why would you consider explanations other then it being true more satisfactory or more believable than that they were telling you the truth?
And would you really believe them without wanting to see just a little evidence? I suggest that you wouldn't believe a word of it. And yet when religious people read about, or are told about, miracles, they believe what they are told, yet nowhere in all that was there ever more than one person telling another something that you would never have believed had they told you first hand. The story has been given a spurious gloss of credibility by being repeated by authority figures - authority figures who had no more basis for belief that you did.
This is how the church uses its 'authority' to persuade people to believe the unbelievable. Believing everything the church teaches by faith simply means the church has not yet found your lower limit of credulity.
As John W Loftus points out, Christians have a double burden of proof when it comes to proving miracles.
On the one hand, they must show that a particular "event" was not very likely...So here is a simple challenge for any Christian. Take any miracle you wish and which you believe, and explain why a non-believer should believe it really happened and that the cause could only have been the Christian god. After all, if you believe in said miracle, that must be what you believe, so all you need do is explain the rational basis for your belief. It is not enough to say that someone else believes it.
On the other hand, Christians must show that the purported miraculous event happened. And yet, everything they say to establish the first burden of proof takes away the strength of the second burden of proof. That is, the more they argue that an event was miraculous, the less likely such an event occurred. But the more they argue that an event was likely to have occurred, then the less likely that event can be understood as miraculous.
The only way people judge whether or not a miracle occurred is whether or not it fits within their control beliefs (i.e., which God he believes in and was taught to believe). One cannot start with the evidence for a miracle to show that the Christian God exists, simply because a person must already believe it’s plausible for the Christian God to exist in the first place (unless it’s a case of accepting what someone says because that person is believable). Otherwise, the evidence isn’t evidence for anything, much like how the evidence in a criminal trial isn't evidence of anything since the prosecutor and defense attorney will have two different ways of seeing that evidence based in separate control beliefs. And yet, how is it possible to believe in the Christian God in the first place without the cold hard evidence that will lead him to believe? The explanation of a self-authenticating witness of the Holy Spirit doesn’t solve anything.
What could be easier than that?
If you can't, you might like to consider exactly why you believe it yourself.