The following is a summary of the major BIBLICAL data which clearly shows that the days of creation in Genesis 1 are literal 24-hr days. It is by no means exhaustive, since such a presentation would fill an entire book (I am writing one at the moment!). Since my training is primarily in theology, hermeneutics and Biblical languages the presentation only discusses scripture and not science.

Note that the major scientific evidence for non-literal days (ie. an old earth), is starlight travel, radiometric dating methods and geological features. For scientific discussions of these see the following (which are again just a small sample. Many more discussions can be found in Creation Ex Nihilo Technical Journal and Creation Research Society Quarterly):

Starlight Travel
D. R. Humphreys, Starlight and Time, Master Books, Green Forest, AR, 1994.
D. R. Humphreys, "New Vistas of Space-Time Rebut the Critics," Creation Ex Nihilo Technical Journal  12.2 (1998), pp. 195-212.

Radiometric Dating
J. Woodmorappe, The Mythology of Modern Dating Methods, ICR, 1999.
A. Snelling, "Dubious Radiogenic Pb Behavior Places U-Th-Pb Mineral Dating in Doubt"  Impact 319, ICR, 2000.
A. Snelling, ""Excess Argon": The "Achilles' Heel" of Potassium-Argon and Argon-Argon "Dating" of Volcanic Rocks" Impact 307, ICR, 1999.
A. Snelling, "Potassium-Argon and Argon-Argon Dating of Crustal Rocks and the Problem of Excess Argon" Impact 309, ICR, 1999.
S. Austin, "Excessively Old "Ages" For Grand Canyon Lava Flows" Impact 224, ICR.

Geology
S. Austin, Grand Canyon: Monument to Catastrophe, ICR, 1994.
T. Walker, "Geology and the Young Earth" Creation 21.4 (1999). pp. 16-20.
G. Berthault "Genesis and Historical Geology: A Personal Perspective" Creation Ex Nihilo Technical Journal  12.2 (1998), pp. 218-221.
P. Julien, Y. Lan, & Y Raslan "Experimental Mechanics of Sand Stratification" Creation Ex Nihilo Technical Journal  12.2 (1998), pp. 213-217.

Philosophy of Science
T. S. Kuhn, The Structure of Scientifc Revolutions,
(This book is an absolute MUST for those who think that you can't dispute scientific "facts".
 

1. yom + numerical = 24-hr day

The first argument is that yom + numerical always refers to a normal 24-hr day.

Don Stoner (A New Look at an Old Earth, pp. 46-48) however, claims that this is not true. He cites Zech 14:7 as an example.

Zech 14:7 states: "It will be a unique day, without daytime or nighttime--a day known to the LORD. When evening comes, there will be light."

The day mentioned here is obviously the same day mentioned in vv. 1, 4 and 6. Since "a text without a context, is a pretext" we need to examine the immediate context of these verses.

It should be abundantly clear from v. 5 that on "that day" the Lord will come. It describes a time-space _EVENT_ in the future. How can the coming of the Lord take a long period of time? It is an event: at one moment on that day, He is not here - the next moment He has returned!

Don, however, believes it refers to the New Jerusalem, the eternal state. But if the "day" refers to the eternal state - an indefinite period of time - it could hardly be called "unique"!

Therefore, the "unique day" in Zech 14:7 does indeed refer to a literal 24-hr day.

Others have suggested Hosea 6:2 as an exception:
"After two days he will revive us;  on the third day he will restore us,  that we may live in his presence."

However, this verse is set in poetic parallelism - and parallelism of a specific kind. This parallelism is a common Semitic device which takes the form X // X + 1 (see Job 5:19; Proverbs 6:16; 30:15, 18; Amos 1:3, 6, 9 for more examples). Given that these instances are part of a well defined Semitic device, they must be interpreted in accordance with that device. In this case, the use
of "two days" and "three days" communicate that the restoration mentioned in the previous verse, will happen quickly and surely (See Cohen/Vandermey, Hosea & Amos, Epositors Bible Commentary). Therefore, these instances must refer to normal days as opposed to long periods, otherwise the device would lose its meaning ie. the restoration would _not_ be quick and sure if the days were long periods of time. There may also be a subtle prophetic allusion to the restoration of humanity after the death and resurrection of Christ - especially since virtually all the content of Hosea serve to prophetically illustrate future events. Again, this demands that the days be taken as 24-hr days.

Bradley and Olsen ("The Trustworthiness of Scripture in Areas Relating to Natural Science" in Hermeneutics, Inerrancy, and the Bible, Radmacher and Preus, eds. [Zondervan, 1984]) also object to this line of reasoning:
"There is no other place in the Old Testament where the intent is to describe events that involve multiple and/or sequential, indefinite periods of time. If the intent of Genesis 1 is to describe creation as occurring in six, indefinite time periods, it is a unique Old Testament event being recorded. Other descriptions where "yom" refers to an indefinite time period are all for a single time period. Thus, the absence of the use of "yamim" for other than regular days and the use of ordinals only before regular days elsewhere in the Old Testament cannot be given an unequivocal exegetical significance in view of the uniqueness of the events being described in Genesis 1 (i.e, sequential, indefinite time periods)."

The first problem here is that they assume what they are trying to prove ie. that the authors intent was to describe sequential indefinite periods of time. Secondly, "yom" by itself does not refer to an indefinite period of time. It only has this extended meaning when it is modified by a prepsoition such as "be" (eg. Gen 2:4). However, none of the instances in Genesis 1 are modified in this way. In addition, Numbers 29:12-35 also describes a numbered sequence of days which are clearly literal 24-hr days.

Thus the pattern of yom + numerical = 24 day does indeed hold.
 

2. The use of ereb and boqer (morning and evening)

The next argument is the use of evening and morning (ereb and boqer) as an idiom for a literal 24-hr day.

Don Stoner (pp. 45-46) objects to this by stating that these word are used together many times to refer to longer periods.

First he states that the use of "day and night" often refers to a continuous time. A store that is open "day and night" is open all the time. However, this analogy is irrelevant since we are not talking about "day and night" but about "evening and morning". Day and night essentially run into each other so that a store open day and night would be open all the time. However, a store that is open morning and evening would only be open for a short period in the morning and a short period in the evening but closed during the day and closed during the night. Thus Don's analogy fails. In any case, analogies are only illustrative, they don't constitute a proof or argument.

Don then cites Ex 18:13-14: "The next day Moses took his seat to serve as judge for the people, and they stood around him from morning till evening." When his father-in-law saw all that Moses was doing for the people, he said, "What is this you are doing for the people? Why do you alone sit as judge, while all these people stand around you from morning till evening?"

He argues that the context implies that Moses was spending all his time judging, day after day. This may be true but the question is what specifically does "from morning till evening" actually mean? "From morning till evening" clearly means from when the sun comes up to when the sun goes down" ie. "all day". It does not mean day after day. We can of course deduce that this was happening day after day because Jethro advised to appoint other judges, but this comes from the wider context not the phrase
"from morning till evening" itself. Thus "from morning till evening" indicates that Moses was judging "all day" and the appointment of judges implies that this was happening "day after day."

Don also points to Ex 27:21 (and Lev 24:3) which states: "In the Tent of Meeting, outside the curtain that is in front of the Testimony, Aaron and his sons are to keep the lamps burning before the LORD from evening till morning. This is to be a lasting ordinance among the Israelites for the generations to come."

As I have pointed out before, this is a bizarre argument. There is simply no way that "from evening till morning" can possibly refer to an indefinite period of time. "From evening till morning" means that the lamps were to be kept burning "all night". They would not have been kept burning all the time, since there would be no need for them during the light of day, and of course whenever the Israelites moved camp they would not be burning either. I find it hard to imagine how such a twisted interpretation can be gleaned from these verses.

In any case, none of the above verses is grammatically parallel to the instances of "evening and morning" in Gen 1. All the above instances are preceded by prepositions, but the instances in Gen 1 are independently conjuncted.

The closest grammatical parallel is Dan 8:14, where ereb and boqer are conjuncted together and refer to a literal 24-hr day: "He said to me, 'It will take 2,300 evenings and mornings; then the sanctuary will be reconsecrated.'"

Gen 1 has "wayehi ereb wayehi boqer" (and then there was evening and then there was morning). Dan 8:14 however has "ereb boqer" (evening [and] morning). The "and" is elliptical (a common occurrence in Biblical Hebrew) and we would not expect to find the verb "wayehi" used here, since Dan 8:14 is direct speech whereas Gen 1 is narrative.

Don argues that "ereb boqer" in Dan 8:14 refers to a period of 2,300 days. However, this is incorrect. It is true that "ereb boqer alpayim ushlsh meot" refers to a period of 2,300 literal days but we are only interested in what "ereb boqer" means. Therefore, if the modifier "alpayim ushlsh meot" (2,300) is dropped, it is clear that "ereb boqer" refers to a single day.

Don has also argued that the compound clause "wayehi ereb wayehi boqer" terminating each day should be translated as "and there was evenings and there was mornings". Since ereb and boqer have no plural form they could be translated as plurals (as in Dan 8:14). Therefore, each creation "day" represents a long span of "evenings and mornings".

Again, this is very poor exegesis. "ereb" and "boqer" may only be translated as plurals IF the context makes it clear that this is necessary. In the case of Dan 8:14, ereb and boqer are modified by the number "2,300" - an obvious indication that the plural should be used. However, there is no such modication in Gen 1, or any other contextual data to suggest that these words should be translated as plurals. In fact the context demands a singular translation, since the verb "wayehi" is singular so "ereb" and "boqer" must also be singular.

In any case, both ereb and boqer are preceded by a waw-consecutive. Therefore, if they were translated as plurals, it would imply that there was a long span of evenings and then a long span of mornings, which is, of course, complete nonsense.
 

3. Exodus 20:11 and 31:17

The 3rd argument for literal 24-hr creation days are the references to the creation days in Ex 20:11 and 31:17. These verses clearly state that the creation was completed in 6 literal ordinary work days.

Don Stoner objects (pp. 48-50) by arguing that sabbath days are merely a shadow of the eternal state, and that it is unsafe to come to conclusions about the length of an object by looking at its "shadow". He quotes Col 2:16-17 and Heb 8:5.

The above is certainly true, but it is completely irrelevant to the present discussion. Don is either completely confused about the whole concept of "types" or "shadows", or is trying to netralise this argument by "bait and switch".

The sabbath is a type of the eternal state, but, as Don pointed out, you can't come to conclusions about the length of this eternal state based on its shadow, which is the sabbath. Now it should be obvious that this has absolutely no bearing at all on the length of the days of creation since they are not even mentioned in the verses Don cites. The discussion is about the length of the days of creation, not the length of the eternal state.

Don goes on to cite Lev 25:3-4 as proof that such shadows apply directly to the working week: "For six years sow your fields, and for six years prune your vineyards and gather their crops. But in the seventh year the land is to have a sabbath of rest, a sabbath to the LORD. Do not sow your fields or prune your vineyards."

However, this verse does not even mention the working week! Rather, it talks about years NOT days! Neither does it have the causal explanation "For in six days the LORD made the heavens and the earth, the sea, and all that is in them, but he rested on the seventh day" found in Ex 20:11 and 31:17. In these verses, the use of "ki" ("for, because") at the beginning of v. 11 indicates the creation week is the very basis of the working week.

Similarly, Gleason Archer argues that Exodus 20:11 does not demonstrate the creation days were 24 hours, any more than the eight day celebration of the Feast of Tabernacles proves the wilderness wonderings, under Moses, lasted for eight days. But again, this is an invalid comparison. Although, the Feast of Tabernacles is prescribed to last for eight days (Leviticus 23:34-36), it does not contain the causal explanation "For in six days�" found in Exodus 20:11.

Don further states (p. 49) "...we really ought to reflect that God's week is not a shadow of ours but that ours is a shadow of His." Presumably, his reference to "God's week" means the creation week. However, this statement is again false. Firstly, types and shadows always precede the real thing - yet Don has it the other way around. Secondly, Ex 20:11 explicitly states that the creation week is the very basis of, and the reason for, our working week!

Next, Don appeals to the mention of the sabbath rest in Hebrews 4 in order to argue that the Sabbath is still continuing, and therefore that at least the 7th day is longer than 24-hrs. However, Don does not even bother to exegete the passage - he just asserts that what he has said is true, but a closer look at the passage clearly shows that this assertion is completely
wrong.

A detailed exegesis of Hebrews 4:1-11 may be found here.
 

4. Use of yom instead of 'olam

The next argument is the use of "yom" instead of the use of "olam".

If the days are long periods of time then "olam" would be a more suitable word to use in order to communicate that meaning.

Don Stoner, however, contends that "olam" means "forever", in which case this would not be the most appropriate word to use.

But this is an unnecessarily narrow definition of the word "olam." The Princeton-BDB Lexicon give the definitions "long duration, antiquity, futurity". Theological Wordbook of the Old Testament (TWOT) states that the word "...is not confined to the future", but can be used to describe something that happened long ago "but rarely, if ever, points to a limitless past" and that the word does not in itself contain the idea of endlessness which "is shown both by the fact that they sometimes refer to events or conditions that occurred at a definite point in the past and also by the fact that sometimes it is desirable to repeat the world, not merely saying "forever", but "forever and ever."

TWOT goes on to say that "olam" was used to refer to a long age or period of time, although there is no instance of this usage in the OT. In the LXX, "aion" was used to render "olam" and this word certainly contains the idea of a long age or period.

Therefore, if the days of Gen 1 were meant to be understood as long ages, "olam" would have been a far better choice than "yom".
 

Conclusion

There is also quite a bit of other evidence suggesting the days are literal 24-hr days, but at least 3 of these 4 arguments are pretty much conclusive in showing that the days of Gen 1 MUST be 24-hr days. When all this evidence is taken together it is simply overwhelming! There should be no doubt at all that these days are indeed 24-hr days.

Given that scripture is inspired by God, is authoritive and inerrant then it doesn't matter how convincing scientific arguments sound they simply cannot be a correct interpretation of the data!

Only scripture is inerrant - the natural world is not. Indeed, the natural word is fallen and under a curse.

I suspect that OECs will simply attempt to dismiss these arguments by claiming that God's word is inspired, but my interpretation is not. However, this would only be true if my interpretation does not match what the author intended to communicate. I have offered a solid exegetical basis for my interpretation and at the same time refuted some common objections.

It is simply not good enough to protest "that's just your interpretation". Firstly, this is bordering on existentialism. Such protests also
inadvertantly deny the possibility of knowing truly (a subtle form of agnosticism). If anyone has a problem with my interpretation then I challenge them to show me what is wrong with it.