Marc A. Moniz
Yes, this is a common misconception. Scientific theories are not speculations or even well-supported hypotheses. A scientific theory is a coherent body of interconnected statements, strongly supported by evidence and based on reasoning that exaplains observations or phenomena. It is a complex of statements and thus does not stand or fall on the basis of a single critical test. Theories evolve as they are confronted with new data. Parts of the theory may be discarded or modified and new parts may be added as new information is gathered. It is the best explanation that we have based on the evidence that we have at the time, whether it's the Wave Theory or Particle Theory; the String Theory, Bubble Theory, or Big Bang Theory; or if it's Lamarkism, Darwinsim, or the Modern Synthesis.