This does not mean that a scientist cannot speculate and ask "What if?"

Some British scientists have speculated that 75 more people will die of the disease in the next 20 years.

Scientists have written and speculated on different aspects of energy accounting.

Scientists have speculated for years about the effects of climate warming.

Indeed, some scientists speculate that that is just what they are.

The scientists speculate that the source of the pollution is from burning candles.

Some scientists speculated at first that the patients had somehow rid themselves of the virus.

Scientists speculate that the coevolution of these two species could have begun 60-70 million years ago.

Scientists speculate that the earth here tried but failed to separate 600 million years ago, creating a weakness of some kind beneath the ground.

Scientists can only speculate on what is causing these powerful radiations.