Parable of the Invisible Gardener

The Parable of the Invisible Gardener is a tale told by John Wisdom. It is often used to illustrate the perceived differences between assertions based on faith and assertions based on scientific evidence, and the problems associated with unfalsifiable beliefs. The tale runs as follows:

"Once upon a time two explorers came upon a clearing in the jungle. In the clearing were growing many flowers and many weeds. One explorer says, 'Some gardener must tend this plot.' The other disagrees, 'There is no gardener.' So they set up a barbed-wire fence. They electrify it. They patrol with bloodhounds. But no shrieks ever suggest that some intruder has received a shock. No movements of the wire ever betray an invisible climber. The bloodhounds never give cry. Yet still the Believer is not convinced. 'But there is a gardener, invisible, intangible, insensible to electric shocks, a gardener who has no scent and makes no sound, a gardener who comes secretly to look after the garden for which he loves.' At last the Skeptic despairs, 'But what remains of your original assertion? Just how does what you call an invisible, intangible, eternally elusive gardener differ from an imaginary gardener or even from no gardener at all?'"

References

* P.A.S., 1944-5, reprinted as Ch. X of Logic and Language, Vol. 1 (Blackwell, 1951)
* Philosophy and Psychoanalysis (Blackwell, 1953)
* Philosophy of Religion (Pojman, 1998)