In some speculative grand unified theory it may decay with a half-life equal to that of the Universe.

He was also scornful of the speculative theory of phrenology.

Another good set of speculative theories washed out.

There are few facts, but scores of speculative theories.

Fire caused by lightning is one speculative theory of their origin.

Judge Jackson relied instead on far more speculative theories of potential harm.

Having established their basic model, the authors go on to describe their speculative theory of the processes involved (see Figure 4.2).

The sarcasm used here to appy to that ridiculous and speculative theory was very appropriate.

It is used in certain speculative theories, such as on the construction of wormholes.

To solve those problems, some physicists have developed a grander and much more speculative theory called supersymmetry.