Adverb
in theory; according to the assumed facts
in a theoretical manner
Source: WordNetEverything is theoretically impossible, until it is done. Robert A. Heinlein
The theoretically unrestricted right to develop power, to wage war against other states, is antisocial and is doubly dangerous, because the state as a mass entity represents a low moral and intellectual level. Christian Lous Lange
To picture world history as advancing smoothly and steadily without sometimes taking gigantic strides backward is undialectical, unscientific and theoretically wrong. Vladimir Lenin
If one introduces the concept of energy of an earthquake then that is a theoretically derived quantity. Charles Francis Richter
I would say that it was 'poetry' which distinguishes the cubist paintings which Picasso and I arrived at intuitively from the lifeless sort of painting which those who followed us tried, with such unfortunate results, to arrive at theoretically. Georges Braque
Spiritual realization is theoretically the easiest thing and in practice the most difficult thing there is. It is the easiest because it is enough to think of God. It is the most difficult because human nature is forgetfulness of God. Frithjof Schuon