The question appears to me to be so completely open and shut, so flatly black and white, that the interesting and important question is the psychological and emotional motive for attributing the tree of life to Darwin. We need to ask why the delusion, not whether the evidence is reasonable. The political content of the blogs that attribute the tree of life to Darwin, provide evidence of a motive.

It is probably impossible to say who had priority. If Darwin knew, he would have told us.

What I examine is not who had scientific priority in proposing common descent and the tree of life, but present day madness and evil.

4) The idea of family trees (of human families) was – I presume – common at the time. Any structurally similar notion concerning life should, by default, be taken to have been understood and intended to be understood on the model of a genealogical family tree by both Lamarck and his audience, unless it is clearly proven otherwise. The analogy ought at any rate to have occurred to him and if Lamarck did not agree with the analogy he should have added a disclaimer.

1) It is our own most natural interpretation of the comments and illustrations so far shared. Really, we should start with our own natural interpretation of a text, and be moved off it reluctantly. The alternative is for the world’s texts to be opaque (e.g., “he said, ‘it is raining’”, but I have no idea what he said, never mind that my natural interpretation of “it is raining” is that it is raining).

2) It is the natural default interpretation of any diagram that the items in the diagram be one to one with concrete things. Granted, not all diagrams are necessarily like this but it is the place to start. Consider it a kind of Occam’s Razor for the interpretation of diagrams: don’t multiply represented entities beyond necessity.

3) It is apparently what Lamarck’s own mentor Buffon believed, as I described previously. Lamarck should be presumed (a) to know what Buffon believed, and (b) to have shared Buffon’s views unless otherwise specified. This is surely the default interpretation of anyone’s views – that if they are the student of a person and they do not clearly repudiate the teacher’s views, then the assumption ought to be that they share those views.

4) The idea of family trees (of human families) was – I presume – common at the time. Any structurally similar notion concerning life should, by default, unless it is clearly proven otherwise, assume to have occurred to Lamarck, and if Lamarck did not agree with the analogy he should have added a disclaimer.

5) It is true. The truth does have a way of letting itself be known, and if someone makes a statement which might be interpreted one way, and might be interpreted another way, it is common practice (and correct practice) to interpret the the statement one way. In fact, this is how English works. A lot of sentences stated in English are intrinsically ambiguous. They could, by themselves, mean many things. They are interpreted in one way based on context and based largely on what would make them true. This, by the way, applies even to statements which are false. People regularly misspeak, and are automatically corrected in the minds of their listeners, and this should be the case.

6) Even those who argue against it seem to admit it to some degree. See for example the comments of Ray Martinez in Panda’s Thumb blog. He is forced to admit:

“Lamarck’s view was predominantly ladder and not branching. You are misapplying the exception to be the norm.”

He initially argued that “Lamarck postulated a ladder concept, quite different from branching tree.” He backed away from this and said that the branching that Lamarck did indeed accept was “the exception” rather than “the norm”. Well, even if we are to take Martinez at his (second) word (and we now have reason to distrust him) that is perfectly compatible with common ancestry. A scientist might believe that the vast majority of evolution takes place without branching but that nevertheless the tree does very occasionally branch and that the entire tree is a single tree.

7) The evidence so far supplied against the interpretation of Lamarck as postulating an actual tree (as opposed to, as the critics argue, a mere formal tree) ranges from nonexistent (mere assertion) to ambiguous.

For example, Wikipedia states, “Buffon considered the similarities between humans and apes, and the possibility of a common ancestry.”

The alternative genetic inference et al. offer of Lamarck should not be the default interpretation of his words insofar as they have been presented here and in the other blog entries, assuming that the material I have found about Buffon is correct. If someone wants to interpret Lamarck in some way other than the default, they need to provide evidence if they expect someone to believe them. This they have not provided in the entries linked to. They merely assert that it is so.