4015 Baker’s Dozen by Adam

The new Listener year began this week with a fairly gentle puzzle from Adam, making his 53rd appearance in the series.

Using one of the letter O’s twice, the set of letters in the asterisked cells could be arranged to spell COGITO ERGO SUM (I think, therefore I am), a phrase associated with RENE DESCARTES. Therefore, in the asterisked cells, we had to replace the letters of COGIT(O) ERGO SUM with the corresponding letters in RENE D(E)SCARTES to make new words (E for O being duplicated in the substitution code).

Final grid entries are indicated by []

ACROSS

1 Go back round as in a trip (6)
OUTING [RETINA] GO reversed, containing UT (as) + IN
5 Mistake? Not a dreadful lot (6)
KISMET [KISSED] Anagram MISTAKE, less A
10 See this structural description bringing possible acclamation (10)
ANATOMICAL Anagram ACCLAMATION, less C (See)
12 Enzyme has run out, doctor finding meagre holding (8)
THROMBIN RO (run out) + MB (doctor), all inside THIN (meagre)
13 With sex appeal a girl almost shows presentational style (6)
ITALIC IT (sex appeal) + ALIC(E) (girl, less last letter)
14 One's getting tipsy for a long time (4)
AEON AE (One) + ON (tipsy)
Care is needed here to avoid ANON, which is also justified by the wordplay
15 One socially inept cowman drops two articles (4)
NERD NEATHERD (cowman), less A + THE (two articles)
17 Frost enthralling a college as a poet (6)
HORACE HORE (frost) containing A + C (college)
19 Showing a pleasing demeanour starts to get ready with lodging (8)
GRINNING First letters of G(ET) R(EADY), + INNING (lodging)
22 Pointed device is turning out cert in 27 (8)
PLECTRUM ECTR (Anagram of CERT) inside PLUM (the answer to 27 Across)
25 Fine silk fabric shows there's a doctor in the house (6)
MADRAS A + DR (doctor), all inside MAS (house)
26 Ornamental panel is incomplete tooth (4)
MOLA MOLA(R) (tooth, less last letter)
27 Plop down unfinished fruit (4)
PLUM PLUM(P) (plop down, less last letter)
29 Start and practically finished in a manner of speaking (6)
JARGON JAR (Start) + GON(E) (finished, less last letter)
31 Transport with rail involved resistant to movement being short of time (8)
AIRLINER AIRL (anagram of RAIL) + INER(T) resistant to movement, less last letter)
32 To prevent a painful state (no pun intended!) you need cleansing (10)
DETERGENCE DETER (To prevent) + (PUN)GENCE (a painful state, less PUN)
33 Sway the tree, awfully hard to fall out (6)
TEETER [TESTER] Anagram of THE TREE, less H (hard)
34 College has to admit, West Point's a military one (6)
CENTER [RENTER] C (College) + ENTER (to admit)
The second use of C = college as a wordplay element

DOWN
1 A letter and its form - that's making progress on galley (6)
OARING [RACING] O (A letter) + A RING (the form of a letter O)
2 A river in Germany yields tree (8)
TAMARIND TAMAR (A river) + IN + D (Germany)
3 It will reveal a poet who has lost her bearings (4)
IT’LL SITWELL (A poet), less S,W and E (compass bearings)
The poet being Edith Sitwell
4 Naming a bird is lacking an idea! (6)
NOTION NOMINATION (Naming); less MINA (a bird)
5 Expressionist painter could make kern rich (8)
KIRCHNER Anagram of KERN RICH
The painter in question being Ernst Ludwig Kirchner
6 Screen idol? (4)
ICON Two definitions, with the whole clue doing double duty. The one referring to a computer icon is justified by idol = “an image”, but the anachronistic usage requires the question mark
7 Turning it round would make this fruit capital (6)
SAMARA If SA (it ie sex appeal) was reversed this would spell ASMARA (capital of Eritrea)
8 Group of plants cultivated in a pale colour friend dismissed (10)
ERIOCAULON Anagram of IN A PALE COLOUR less PAL (friend)
9 Wantonness offers matters of some weight (6)
TONNES [DENNET] Hidden in WanTONNESs
11 Take out of time a bird found in water on rocky isle (10)
ETERNALISE TERN (a bird) inside EA (water), + LISE (anagram of ISLE)
16 Note with replies fermented beer (8)
PILSENER Anagram of N (Note) + REPLIES
18 Chopped tarragon is presumptuous (8)
ARROGANT Anagram of TARRAGON
20 Reveal as even-handed missing third (6)
IMPART [EMPART] IMPART(IAL) (ie even-handed, minus last third)
21 Gun permit displayed by captain? (6)
ARMLET ARM (Gin) + LET (permit)
23 Take away from platter a load (6)
CHARGE R (Take) removed from CHARGER (platter)
24 Trough shows disease resistance (6)
MANGER [MANNER] MANGE (disease) + R (resistance)
28 A canard? Another bird (4)
KITE Two meanings
30 China's extremely put out to get nothing from the French (4)
RIEN FRIEND (China), less first and last letters