Today’s New Reason To Believe

Thinking clearly about Christian truth is critical. Let’s examine the Trinity doctrine further by making three more essential points as to what the Trinity is and isn’t.

First, the members of the Trinity are qualitatively equal in attributes, nature, and glory. While Scripture reveals a voluntary subordination among the divine persons in terms of position or role (for example, the Son submits to the Father; the Spirit proceeds from the Father and the Son), there exists absolutely no subordination (or inferiority) of essence or nature. The persons are therefore equal in being, but subordinate only in role or position.

Second, the members of the Trinity are both eternally and simultaneously distinct as three persons. In other words, the Godhead has forever been, is now, and will forever subsist as three persons. None of the persons came into being or became divine at a given moment in time.

Third, the three members of the Godhead are distinct persons and can be distinguished from each other (the Father is not the Son, the Father is not the Holy Spirit, and the Son is not the Holy Spirit). Orthodox Trinitarianism therefore rejects all forms of modalism (that blends or confounds the persons by defining them as mere modes of existence). God’s “oneness” and “threeness” are in different respects.

The one true God is revealed in three distinct but not separate persons.

To quote the ancient Athanasian Creed:

Thus the Father is God, the Son is God, the Holy Spirit is God. Yet there are not three gods; there is but one God.

For more on the historic Christian doctrine of the Trinity, see “How Can God Be Three and One?” in Kenneth Samples’ book Without a Doubt: Answering the 20 Toughest Faith Questions.

In addressing audiences about the fine-tuning of the cosmic expansion rate, I have used the illustration that adding or subtracting a single dime to the mass of the observable universe would be enough of a change to make physical life impossible. This word picture helps to demonstrate a number used to quantify that fine-tuning, namely 1 part in 10⁶⁰. Compared to the total mass of the observable universe, 1 part in 10⁶⁰ works out to about a tenth part of a dime.

Let’s consider a universe that contains only matter. If the matter density is sufficiently large, gravity will overcome the expansion and cause the universe to collapse on itself. If the density is sufficiently small, the cosmos will continue to expand forever with negligible slowing. If the density is just right, the universe will expand forever, but continually slow down its expansion rate until it becomes static at an infinite time into the future. In a universe that contains only matter, this corresponds to a “flat” geometry for the universe. Life and flatness are related because only a flat universe meets two life-essential requirements. First, a flat universe survives long enough for an adequate number of generations of stars to form that will make the heavy elements and long-lived radiometric isotopes that advanced life requires. Second, a flat universe expands slowly enough for the matter to clump together to form galaxies, stars, and planets, but not so slowly as to form only black holes and neutron stars.

Until the mid-1990s, astrophysicists found it remarkable that the universe was so close to a flat geometry because such flatness is unstable with respect to time. Even though they could detect only about 4 percent of the mass required to make the universe flat, this required the early universe to be exquisitely close to flat—to within one part in 10⁶⁰. The previous statement holds true even given the uncertainties that existed twenty years ago (and to a lesser extent still do) in measurements of the cosmic mass density. Thus, in the absence of dark energy, the expansion rate would have changed so dramatically that the galaxies, stars, and planets necessary for physical life would never have formed.

Over the past fifteen years the picture has changed significantly. First, measurements of the radiation left over from the cosmic creation event, also known as the cosmic microwave background radiation, confirmed (with an error bar of about 3 percent¹) that the universe is geometrically flat. Second, the concept of an extremely early epoch of cosmic inflation (a brief period of hyperexpansion of the universe when it was less than a quadrillionth of a quadrillionth of a second old) was developed into a scientifically testable hypothesis that later measurements partially confirmed.² Third, astronomers discovered another density parameter for the universe, namely space energy density or what is now known as dark energy. For most astronomers and physicists an early epoch of cosmic inflation solves the one part in 10⁶⁰ fine-tuning problem because such inflation in the early universe drives it exquisitely close to a flat geometry regardless of the universe’s initial mass density.

A cosmic fine-tuning problem remains, however. The total cosmic mass density measured through several independent methods falls short by a little more than a factor of three from that required to make a flat-geometry universe,³ which measurements of the cosmic microwave background radiation have established. Dark energy comes to the rescue to make up the deficit, but not without a price. By any accounting, the source or sources of dark energy are at least 120 orders of magnitude larger than the amount detected. This implies that somehow the source(s) must cancel so as to leave just one part in 10¹²⁰ in order to match the small amount of dark energy detected by astronomers. Therefore, while inflation and dark energy can “eliminate” the one part in 10⁶⁰ fine-tuning in the mass density of the universe, they can only do so by introducing the far more exquisite one part in 10¹²⁰ fine-tuning in the dark energy density.

RTB scholars Jeff Zweerink and Dave Rogstad contributed to this article.

1. D. N. Spergel et al., “Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Cosmology,” Astrophysical Journal Supplement Series 170 (June, 2007): 377-408.
2. D. N. Spergel et al., 392-94.
3. D. N. Spergel et al., 379-90.

The discussion continues from last week and ends here.

The last description (made in Part 6) leads to an important observation. So far, I’ve discussed and illustrated the projection and the unfolding of various “cubes” into lower dimensions. But what happens if a higher-dimensional cube is simply inserted into a lower dimension so it intersects that dimension? Say, for example, we insert a 3-D cube into a 2-D space (a plane). Assuming it is inserted “square-on” rather than at an angle, what we see in the plane is a single square. This is illustrated in Figure 6.

In an analogous way, a 4-D hypercube can be inserted into a 3-D space. Unfortunately, we can’t draw a diagram that shows a 4-D cube intersecting a 3-D space. However, a person living in this 3-D space would see a 3-D cube just like in Heinlein’s fictitious story from Part 1 (assuming, again, that it intersects “square-on”).

At this point we can evaluate whether higher-dimensional thinking is useful for understanding difficult doctrines of the Bible. Beginning with a two-dimensional universe, imagine that a person living in this universe encounters the projection of a 3-D cube as seen in Figure 1. A 3-D person looking down on this world from the perspective of three dimensions will immediately describe it as the projection of a 3-D cube in his world, and will recognize that the various angles are right angles (90 degrees). On the other hand, the 2-D person will see two squares (cubes in his world) connected by some lines. If the 3-D person somehow communicates with the 2-D person (say via a written message), and states that all the angles are right angles, the 2-D person will disagree. Such a claim contradicts his measurements.

On the other hand, if the 2-D person realizes (after reading a book about higher dimensionality by some guy named Hugh Ross) that his object is the projection of a 3-D cube from a dimension beyond his experience, then he will acknowledge that such a claim about right angles can, in fact, be true. But the 2-D person must first believe in the existence of higher dimensions.

Figure 6: Intersection of a cube and a plane

By analogy, a person living in a three-dimensional universe may encounter descriptions or explanations of phenomena that cannot be correct based on the reasoning processes he normally applies. The only conclusion would be that they are invalid or incoherent. However, it may also be true that an appeal to higher dimensions can possibly resolve the problem, but again, this requires the belief that such higher dimensions exist. When it comes to doctrines such as the Trinity, higher-dimensional reasoning has helped some people resolve the difficulty. However, we must remind ourselves that a revealed doctrine about the nature of the God of the cosmos is ultimately beyond—but not against—reason.