People in the 17th and 18th centuries were very optimistic about radical human life extension.

Read 'people' as prominent thinkers of the period. True: historians document that several prominent 17th- and 18th-century figures (for example Bacon, Descartes, Franklin, Condorcet, Godwin) openly expressed strong optimism about greatly extending the human lifespan, and that this was a recognisable current of the era. Mostly true: such optimism is documented among a few notable thinkers but was not widespread, so 'very optimistic' fits only that group. Mixed: some voiced optimism while views in the period were broadly divided or sceptical. Mostly false: only isolated or ambiguous examples exist. False: no notable figures of the period expressed such optimism.

Set before the research began.

1. E1 ‘A Thing Ridiculous’? Chemical Medicines and the Prolongation of Human Life in Seventeenth-Century England London School of Economics, Department of Economic History (Working Papers on The Nature of Evidence No. 10/06) · July 2006

   “For Bacon, therefore, the quest for immortality was an inherent feature of “The Great Instauration,” his radical plan to overthrow Scholastic learning”

2. E2 A History of Transhumanist Thought Nick Bostrom (Journal of Evolution and Technology, Vol. 14 Issue 1) · April 2005

   “No doubt man will not become immortal, but cannot the span constantly increase between the moment he begins to live and the time when naturally, without illness or accident, he finds life a burden?”

3. E3 William Godwin Stanford Encyclopedia of Philosophy · 16 January 2000

   “will gradually witness the development of the powers of mind to the point that they gain ascendancy over physiological process allowing life to be prolonged indefinitely.”

4. E4 ‘A Thing Ridiculous’? Chemical Medicines and the Prolongation of Human Life in Seventeenth-Century England London School of Economics, Department of Economic History (Working Papers on The Nature of Evidence No. 10/06) · July 2006

   “is it not a thing ridiculous, now in these later times, to extend the life of man-kinde to 1000, 900, or at the least to 600 yeeres?”

Independent historical sources show that several prominent thinkers of the period were openly optimistic about greatly extending human life. A historian describes Bacon treating the quest for immortality as part of his Great Instauration (E1). A passage quoted in E2 speculates that the healthy lifespan could keep increasing, while saying humans would not become immortal. Godwin envisioned life being prolonged indefinitely (E3). E4 records a contemporary calling such life extension "a thing ridiculous", and the evidence does not show this optimism was a widespread current of the era, so it is documented for a notable group of thinkers rather than for the period as a whole.