In science, the favored interpretation is the one that is the most simple, but still fits the evidence at hand. More complicated explanations are always possible, but are less acceptable. This principle in science is called parsimony.

Paleoanthropology is not a normal science. It is a type of historical fiction. Its purpose is to make sense (and cents) of the past, and to inform and entertain the educated public. Evidence should be interpreted in ways that are understandable, but not simple. A simple explanation will often kill a good story.

I have been visiting the Alta petroglyphs (helleristninger) in arctic Norway almost every summer for the past 40 years. This is beautiful rock-art, that has become a UNESCO World Heritage site. There are hundreds of figures carved in the glacially polished and striated rock at Hjemmeluft, Alta. The figures show similar motifs of people, boats, and animals, and were carved using similar techniques and styles. 

Paleoanthropologists say that the oldest carvings are about 6200 years old (4200 BC). The youngest ones were below sea level at that time and cannot be more than about 2500 years old. Paleoanthropologists think that most of them were carved just above sea level as the land rose slowly after the last glaciation. The land is still rising about 2 millimeters per year. This interpretation of carvings near sea level makes them as old as possible, and as interesting as possible.

Paleoanthropologists divide them into four periods: the highest ones, now about 25 meters above sea level, are thought to have been carved from 4200-3600 BC. The other periods of carving were 3600-2700 BC, 2700-1700 BC, and 1700-500 BC.

Artifacts have been found nearby, showing that people were indeed living in this area as early as 10 000 BC. It seems reasonable that the Hjemmeluft petroglyphs were made as early as 4200 BC. But they could have been made by the same artist or artists about 500 BC. Not too far away are two other series of petroglyphs: Storsteinen ('4200-1700 BC') and Amtmannsnes ('2700-1700 BC'). They have different styles and it is obvious that they were made by different artists. 

For paleoanthropologists, ‘older is better.’ For me, ‘simpler is better.’ I think that all the carvings at Hjemmeluft were probably made by the same artist or artists, about 500 BC. I cannot find that this parsimonious (and rather boring) hypothesis is ever mentioned in the published literature. 

Here is a schematic illustration of the ages and styles of the four periods of carvings of Hjemmeluft, Storsteinen, and Amtmannsnes.
See Helskog (1988) Helleristninger i Alta: spor etter ritualer og dagligliv i Finnmarks forhistorie

Financial interest trumps parsimony in paleoanthropologic interpretations...

Alta is a wonderful place to visit in the summer, with 24 hours of direct sun, and no real night from March 26 to September 17. That is when most people visit Alta, as I am about to do with a class of geology students from southern Norway. In prehistoric times, it must have been difficult to survive in Alta during the winter: there is no daylight from November 26 to January 16, and deep snow covers the ground until summer begins in May. 

There are spectacular rock carvings along the fjord in Alta. A parsimonious interpretation would be that the carvings were made by people who visited Alta by boat during the summer, no more than 2000 years ago. But that interpretation is never mentioned by anthropologists. They know that a more interesting and financially rewarding interpretation is that the carvings were made by permanent residents, thousands of years earlier. People are more interested in knowing who might have lived in Alta, not who might have visited Alta. 

This is a typical example of a parsimonious interpretation being avoided in paleoanthropology, because other interpretations will draw more public interest and more research funding. 

The rock carvings do not seem to depict winter scenes. There are no carvings showing northern lights, for example. Many carvings show reindeer, which are in Alta only during the summers. The snow is too deep for them during the winter, so they migrate to colder and drier places inland. I think the prehistoric artists who made the Alta carvings also migrated with the seasons — to Alta in the summers, and back home in the winters. 

No one wants to cast doubt on a $uccessful theory.

I recently paid Alta Museum $14 to view the spectacular rock art on the smooth sandstone rocks near the fjord. It is a UNESCO World Heritage site. During the summer months, up to a thousand visitors each day pay to view those carvings. It is said that the carvings were made by Alta residents during many periods ranging from 7000 to 2000 years ago. 

I have worked a lot with rocks, and have seen a lot of art made by various artists. My wife and children are artists. I can't accept the anthropologists' interpretation that the rock art of Alta was made by different people during vastly different ages, using only rocks as tools. I think that the engravings were made by a few visitors, who drew the figures and then used a hammer and iron chisel to engrave them. Rock engravings at different sites along Alta fjord have different artistic styles, and were probably made by different artists at about the same time. 

If the artists used iron tools, it was during the iron age, not the stone age. I think the engravings were done by Viking-age visitors who came by boat during the summer months. Many of the boats that are depicted have animal heads on the prows, typical of the Viking culture. A Viking-age hypothesis has not been mentioned by anthropologists who study the site. That is because it would diminish the public interest in it.