Not All Birds Can Fly. What Separates

Imagine We Could Accelerate Continuously At 1 G-what We're Comfortable With On Good Old Terra Firma-to The Midpoint Of Our Voyage, And Decelerate Continuously At 1 G Until We Arrive At Our Destination. It Would Take A Day To Get To Mars, A Week And A Half To Pluto, A Year To The Oort Cloud, And A Few Years To The Nearest Stars.

Quickly Capping 363 Oil Well Fires In A War Zone Is Impossible. The Fires Would Burn Out Of Control Until They Put Themselves Out... The Resulting Soot Might Well Stretch Over All Of South Asia... It Could Be Carried Around The World... [and] The Consequences Could Be Dire. Beneath Such A Pall Sunlight Would Be Dimmed, Temperatures Lowered And Droughts More Frequent. Spring And Summer Frosts May Be Expected... This Endangerment Of The Food Supplies... Appears To Be Likely Enough That It Should Affect The War Plans.

And After We Returned To The Savannahs And Abandoned The Trees, Did We Long For Those Great Graceful Leaps And Ecstatic Moments Of Weightlessness In The Shafts Of Sunlight Of The Forest Roof?

Except In Pure Mathematics, Nothing Is Known For Certain (although Much Is Certainly False).

Arguments From Authority Carry Little Weight – Authorities Have Made Mistakes In The Past. They Will Do So Again In The Future. Perhaps A Better Way To Say It Is That In Science There Are No Authorities; At Most, There Are Experts.