Is it true that in science 'theoretical' means 'non-empirical'? If so, are

Is it true that in science 'theoretical' means 'non-empirical'? If so, are

Is it true that in science 'theoretical' means 'non-empirical'? If so, are theoretical entities radically imperceptible? That is, although we can perceive the effects of theoretical entities, we can never perceive the entities themselves. For example, theoretical temperature is average kinetic energy of molecules, which we cannot perceive, but we can perceive its effects as thermometer readings and sensations of hot and cold; or mass is imperceptible but we can perceive its effects as forces of weight and inertia.

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