Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. The same definition is also reproduced by Sharastani, evidently from the ai-najat, in his summary of Avicenna's philosophy (cureton's edition, p. 'and so there is here a measure for motions, corresponding to them, and everything corresponding to motions is something having duration, which duration implies a continual renewal of itself. It is this that we call time.'